Nowadays, there has been an increase and dependent items that affect the quality of the signals
such as the properties of substances in the buildings, objects and humans’ movements, electronic equipment. In
this study, the effects of electromagnetic interference on the functional usage of mobile communications are
examined. The indoor and outdoor attenuation characteristics of 2G, 3G and 4G frequency bands are
investigated. Field strength measurements are conducted in university campusopenarea, along a corridorfield
in a fivestoreyuniversitybuilding, in different floors, and rooms, where normal incidence on plane boundary is of
main concern. This study investigates multilayer model for building structures. The evaluation of measured
values together with the simulated results is compared with literature outcomes. In addition, dependency with
the frequency, power of the waves and existence of trees on the transmission path are also discussed.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Safety zone determination for wireless cellular tower a case study from tan...eSAT Journals
Abstract
Safety zone determination for wireless cellular towers has attracted attention from many researchers in the last decade. This is caused
by the rapid growth of the wireless cellular industry which has led to the installation of towers even in the residential areas. There are
many reports and ongoing researches regarding the biological and thermal effects of wireless cellular electromagnetic fields
exposures to people. Cancer, hyperthermia, neural and behaviour effects of people exposed to these electromagnetic fields have been
reported.
This motivates the research to determine safety zones from wireless cellular towers to assure safety to those living in the vicinity of
these towers. A model for safety zone determination is developed. The model takes the received power at the object, power transmitted
by the transmitter and gain of the transmitter as inputs to determine the safe distance from the radiation of a wireless cellular
transmitter. The power density received by the object and its geographical location from the radiation source are measured using the
selective radiation meter. Transmitted power and the gain of the transmitter together with the height of the tower were obtained from
the respective wireless cellular network operator. Based on the geographical location of the object, the distance from the radiation
source was calculated using the haversine formula. These inputs are then used to determine the safety zone based on the standards
and guidelines developed by WHO and ICNIRP.
Keywords - Safety zone; Power density; wireless cellular tower; Exposure limits.
New modeling approach of laser communication in constellation and through atm...journalBEEI
Laser communication between satellites in the constellation and from the satellites to ground stations offers a gigantic data rate for the users. This principal advantage drives telecom companies to develop this technology to use it like a carrier signal, the most disadvantage of this technology is the need to very complicated pointing systems between the transmitter and the receiver due to a very small beam divergence, continually moving of satellites in orbits and the distance between the satellites (tens of thousands of kilometers). The laser beam suffers continuously from several factors like atmospheric turbulences, internal and external vibrations. All these factors lead to an increase in the bit errors rate and cause degradation in the communication quality. This paper deals with a new method of modelisation of external effects in transmission of signal light from a ground station to the satellite through atmospheric disturbances. Indeed, an in-depth investigation, of the influences of satellite vibrationsinlaser signal transmission between satellites constellation, has been conducted by studying the effect of the intensity of vibrations on the optical signal amplitude. Some solutions are proposed to improve the efficiency of optical satellites communications.
Circular Shape , Dual Band proximity feed UWB AntennaAmitesh Raikwar
Abstract:- This paper presents novel proximity feed, microstrip antenna with dual band operative frequency and having ultra wide bandwidth with center frequency at 3GHz. This Circular shaped microstrip antenna offers a dual band. This paper suggests an alternative approach in enhancing the band width of microstrip antenna for the wireless application operating at a frequency of 3 GHz. A bandwidth enhancement of more than 21% was achieved. The measured results have been compared with the simulated results using software IE3D version-14.0.
A PROXIMITY FEED DUAL BAND CIRCULAR SHAPED ANTENNA WITH SEMICIRCULAR GROUND P...Amitesh Raikwar
In this work, we present a Circular Shaped proximity feed
Microstrip Patch Antenna. The antenna is comprised of circular
shaped radiation patch and this radiating patch is faded
by proximity coupling. The ground plane of the antenna has
Semicircular pattern to improve the coupling level of the
patch. The simulated result shows it provides the return loss
less than -10 dB for two frequencies 1.27 GHz and 1.43 GHz
which could be a useful frequencies for wireless communication
system. The simulation work is carried out on IE3D
software, a product of Zeland Software Company.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Safety zone determination for wireless cellular tower a case study from tan...eSAT Journals
Abstract
Safety zone determination for wireless cellular towers has attracted attention from many researchers in the last decade. This is caused
by the rapid growth of the wireless cellular industry which has led to the installation of towers even in the residential areas. There are
many reports and ongoing researches regarding the biological and thermal effects of wireless cellular electromagnetic fields
exposures to people. Cancer, hyperthermia, neural and behaviour effects of people exposed to these electromagnetic fields have been
reported.
This motivates the research to determine safety zones from wireless cellular towers to assure safety to those living in the vicinity of
these towers. A model for safety zone determination is developed. The model takes the received power at the object, power transmitted
by the transmitter and gain of the transmitter as inputs to determine the safe distance from the radiation of a wireless cellular
transmitter. The power density received by the object and its geographical location from the radiation source are measured using the
selective radiation meter. Transmitted power and the gain of the transmitter together with the height of the tower were obtained from
the respective wireless cellular network operator. Based on the geographical location of the object, the distance from the radiation
source was calculated using the haversine formula. These inputs are then used to determine the safety zone based on the standards
and guidelines developed by WHO and ICNIRP.
Keywords - Safety zone; Power density; wireless cellular tower; Exposure limits.
New modeling approach of laser communication in constellation and through atm...journalBEEI
Laser communication between satellites in the constellation and from the satellites to ground stations offers a gigantic data rate for the users. This principal advantage drives telecom companies to develop this technology to use it like a carrier signal, the most disadvantage of this technology is the need to very complicated pointing systems between the transmitter and the receiver due to a very small beam divergence, continually moving of satellites in orbits and the distance between the satellites (tens of thousands of kilometers). The laser beam suffers continuously from several factors like atmospheric turbulences, internal and external vibrations. All these factors lead to an increase in the bit errors rate and cause degradation in the communication quality. This paper deals with a new method of modelisation of external effects in transmission of signal light from a ground station to the satellite through atmospheric disturbances. Indeed, an in-depth investigation, of the influences of satellite vibrationsinlaser signal transmission between satellites constellation, has been conducted by studying the effect of the intensity of vibrations on the optical signal amplitude. Some solutions are proposed to improve the efficiency of optical satellites communications.
Circular Shape , Dual Band proximity feed UWB AntennaAmitesh Raikwar
Abstract:- This paper presents novel proximity feed, microstrip antenna with dual band operative frequency and having ultra wide bandwidth with center frequency at 3GHz. This Circular shaped microstrip antenna offers a dual band. This paper suggests an alternative approach in enhancing the band width of microstrip antenna for the wireless application operating at a frequency of 3 GHz. A bandwidth enhancement of more than 21% was achieved. The measured results have been compared with the simulated results using software IE3D version-14.0.
A PROXIMITY FEED DUAL BAND CIRCULAR SHAPED ANTENNA WITH SEMICIRCULAR GROUND P...Amitesh Raikwar
In this work, we present a Circular Shaped proximity feed
Microstrip Patch Antenna. The antenna is comprised of circular
shaped radiation patch and this radiating patch is faded
by proximity coupling. The ground plane of the antenna has
Semicircular pattern to improve the coupling level of the
patch. The simulated result shows it provides the return loss
less than -10 dB for two frequencies 1.27 GHz and 1.43 GHz
which could be a useful frequencies for wireless communication
system. The simulation work is carried out on IE3D
software, a product of Zeland Software Company.
Study of user effects on two-port MIMO antennas at 2.4 GHz and 5.8 GHz for Wi...journalBEEI
In this paper, two multiple input multiple output (MIMO) antennas for Wi-Fi/WLAN mobile applications are proposed. The designed two-port MIMO antennas are made up of planar inverted-F antennas (PIFAs). The antenna elements for both designs are symmetrical and placed on the short-edged corners of the substrate used, FR4. The performance of both antennas in the presence of user’s hand is compared in terms of impedance bandwidth and efficiency. An upward shift of up to 0.17 GHz in impedance bandwidth was found for 2.4 GHz and 5.8 GHz antenna. Due to the smaller size of antennas at 5.8 GHz compared to antennas at 2.4 GHz, the antennas are less obstructed by hands and thus the exhibited total efficiency of up to 45.58 % in the presence of human hand. The designed antennas have been fabricated for validation purpose. It is shown that there is a good agreement between simulated and measured results.
Phi shape uwb antenna with band notch characteristicsKiran Ajetrao
In this paper a novel band notch antenna in UWB
frequency range is designed using split rings. Split rings are
overlapped with designed monopole to give phi shape. The slit
gap gives band-notch operation from 5.1GHz to 6.29GHz and
from 4.94GHz to 5.91GHz for SPSSR and SPSCR antennas
respectively. Simulated and measured results are in good
agreement.
Review: Dual Band Microstrip Antennas for Wireless ApplicationsIJAAS Team
In this manuscript, a review of dual band microstrip antennas for wireless communication is presented. This review manuscript discusses regarding the geometric structures, different methods of analysis for antenna characteristics, and different types of wireless applications.
A four-element UWB MIMO antenna using SRRs for application in satellite commu...IJECEIAES
This paper proposes a method for designing a new ultra wide band (UWB) multiple-input multiple-output (MIMO) antenna with two and four elements. First we presented an ultra-wide band antenna we studied these performances. Then, we studied the application of metamaterials to the design of MIMO antennas for miniaturization and the performance of antennas, in order to guarantee the proper functioning of the MIMO system with a much reduced separation distance between the radiating elements (λ/12), where the coupling can be very weak. The application of these circular double ring SRRs materials on the front plan of the antenna has contributed to the increasing of the antenna performance is studied in terms of S-Parameters, efficiency, diversity gain (DG), radiation properties and envelop correlation coefficient (ECC). It offers advantages such as the reduction of weight and congestion that is beneficial for their integration into satellite communications systems.
Design compact microstrap patch antenna with T-shaped 5G applicationjournalBEEI
This paper is presents a microstrap patch with a T-shaped rectangular antenna workings; the T-shaped patch operating at 3.6 GHz resonating frequency range for 5G application (from 2.9 to 4.4 GHz) repectively. The overall size of the proposed antenna is 22×24×0.25 mm3; the feeding technique using a 50 Ω feed line to the antenna. The proposed antenna is printed on compact Rogers RT 588 lz substrate having permittivity (ɛr) 2.00, loss tangent (tan δ) 0.0021, with thikness 0.2 mm. The proposed antenna introducesmany advantages like small size, low profile, and simpler structure. The characteristics such as radiation pattern, reflection coefficient, gain, current distribution, and radiation efficiency are respectively presented and discussed, using CST microwave study in simulating and analysing. Introducing a slot with a rectangular T-shaped patch antenna achieved lower frequency with 98.474% radiation efficiency and peak gain of the proposed antenna at 2.52 dB. The fractional bandwidth is 42.81% (2.90 GHz to 4.48 GHz) with a resonant frequency of 3.6 GHz and return loss at 28.76 dB. This frequency band attributessuited 5 G mobile application.
Cost effective approach for 100 gbps vcsel-mmf lan’seSAT Journals
Abstract VCSELs enable many types of applications, such as optical computing and optical information processing. In this work, firstly different physical parameters Temperature, cavity volume and Bias current have been analysed on VCSEL laser. Further different modulation formats i.e. NRZ, CSRZ and MDRZ are analysed for the first time using VCSEL Laser over GI-MMF in terms of Q-factor and BER.MDRZ comes out to be best modulation formats to prolong the system reach to28Km. Performance analysis of 100 Gbps MIMO system using MDRZ modulation format over 28 km MMF has also been investigated at different distances varied from 8km to 28 km in terms of Q-factor and BER. Keywords: MMF, GI, VCSEL, MDRZ, MIMO
Design Study of a Miniaturized Multi-layered Antenna-in-package for 2.4 GHZ ...IJECEIAES
This paper proposes a novel miniaturization technique to enhance the radiation properties of small multi-layer patch antenna used in packaged circuits. The multilayered antenna design is composed of three layers with different shapes. An enhancement on the radiation properties has been obtained by optimizing the geometry of the radiated element and the parasitic conductor of the middle layer. The whole design has been implemented on the FR4 substrate with dielectric constant of 4.4, thickness of 1.6 mm and Copper thickness of 5 m. The first layer is a driven element while second and the third layer are parasitic patch elements. The optimized multilayer antenna has a very small size of . Considering the small size of the antenna, a detailed study of the parameter affecting the radiation has been considered to force the antenna to operate at 2.4 GHz band. Miniaturization techniques based on the current distribution have been also taken into account to shift down the resonant frequency and reduces more and more the antenna size at the designed operating frequency. The miniaturized antenna maintains performant radiation characteristics in terms of reflexion coefficient, bandwidth and directivity. All developed antennas are simulated using the commercial Electromagnetic CST Microwave Studio software. Achieved results demonstrate a good performance with low cost and compact size
Specific Absorption Rate Assessment of Multiple Microstrip Patch Antenna ArrayTELKOMNIKA JOURNAL
Interaction between electromagnetic field (EMF) radiated from multiple antennas and human body
is crucial to be explored as multiple antennas are the essential implemented devices to achieve the
requirements of the future evolved fifth generation (5G) technology. Thus, this article presents a significant
study of the radiated EMF effect from a single, and multiple antennas towards human through the
assessment of specific absorption rate (SAR). The single antenna, 1 x 2, 1 x 3 and 1 x 4 arrays of
microstrip patch antennas are designed to cover mobile operating frequencies of 0.8, 0.85, 0.9, 1.8, 2.1
and 2.6 GHz. Two types of human head phantoms are implemented in this study, which are specific
anthropomorphic mannequin (SAM) and Voxel head model that placed close to single antenna or antenna
array to investigate the penetration of EMF towards the human tissue. The single antenna or antenna array
is placed with fixed distance of 10 mm from the phantom, which excited by maximum allowable power of
19 dBm in CST Microwave Studio 2016. The effect of the radiated EMF that quantified by SAR parameter,
which depicts satisfying results against the established standard limits at averaged 1g and 10g mass of
tissues for all designated frequencies that utilized for single and multiple antennas.
An Internal Wideband Monopole Antenna for UMTS/WLAN Dual-Mode Mobile PhoneSaou-Wen Su
An internal wideband metal-plate monopole antenna for mobile phone applications is presented. The antenna is easily fabricated by bending a single metal plate and suitable to be embedded within the casing of a mobile phone as an internal antenna. Further, the antenna shows a wide operating bandwidth of about 5 GHz (about 1.8−6.7 GHz), making it easy to cover the UMTS band and the 2.4/5.2/5.8 GHz WLAN bands for mobile/WLAN dual-mode operation for a mobile phone.
Automatic mic adjustment using dc motoreSAT Journals
Abstract
Beamforming theory is used to measure the phase angle between two input signals. Automatic adjustment of height and position of
MIC using dc motors. Horizontal and vertical DC motors are attached with the mic. Microphone array signal processing is to
enhance and extract information carried by acoustic waves received from a number of microphones. Differently placed
microphones are receiving more or less the same signal but with a small time shift. The time delay estimation is calculated using
LabVIEW software.
Keywords - MEMS microphones, beamforming, source localization, DC motor
Microstrip line fed stacked layer e shaped patch antenna for wlanIAEME Publication
The design of stacked layer E-shaped microstrip patch antenna for wideband
operation in the 5-6 GHz frequency range has been presented in this paper. The antenna is
Microstrip line feeded. The Roger RO4350 of 1.6 mm height with relative permittivity of
3.66 and dielectric loss tangent of 0.004 has been used as the substrate on which the patch is
placed. An air box of 2mm height has been introduced between substrate and the ground. The
ANSOFT HFSS software has been used for designing the antenna. High performance
characteristics and good impedance matching have been obtained. The antenna is resonating
at 5.36 GHz with a return loss of -56.5 dB. A maximum gain of 5.3 dB has been obtained in
E-plane. The proposed antenna is suitable for WLAN and WiMax applications operating
within 5.15-5.85 GHz frequency band.
CHARACTERIZATION OF INDOOR PROPAGATION PROPERTIES AND PERFORMANCE EVALUATION ...ijwmn
Indoor wireless systems poses one of the biggest design challenges although it is the most flexible and easily
deployable method of implementing Local Area Networks. This difficulty in predicting the propagation of
radio frequency wave in indoor environments is caused by reflection, refraction, diffraction and scattering
of signals due to closed proximities to furniture, walls, human beings, and reflectors like ceiling, mirrors and
glasses. To help improve the user experience and guarantee good quality of service in indoor situations, the
research investigated the throughput and attenuation effect on signal with respect to 4, 5, 6 and 9 inches sizes
of blocks walls respectively. The characterized Path-loss exponent was 1.999 and differed from the f
Indoor Radio Propagation Model Analysis Wireless Node Distance and Free Space...IJERA Editor
Ultra wide bandwidth (UWB) signals are commonly defined as signals that have a large relative bandwidth
(bandwidth divided by the carrier frequency) or a large absolute bandwidth. Typical indoor environments contain
multiple walls and obstacles consisting of different materials. The RF ultra wideband (UWB) system is a
promising technology for indoor localisation owing to its high bandwidth that permits mitigation of the multipath
identification problem. The work proposed in this paper identifies exact position of transmitter and receiver
wireless nodes, calculates free space path loss and distance between two nodes by considering frequency
bandwidth using 2-point and 3-point Gaussian filter. Also in the paper three types of indoor radio propagation
models are analyzed at ultra wideband frequency range and results are compared to select best suitable model for
setting up indoor wireless connectivity and nodes in typical office, business and college environments and
WPAN applications.
Propagation Path Loss Modeling and Outdoor Coverage Measurements Review in Mi...IJECEIAES
The global bandwidth inadequacy facing wireless carriers has motivated the exploration of the underutilized millimeter wave (mm-wave) frequency spectrum for future broadband cellular communication networks, and mmWave band is one of the promising candidates due to wide spectrum. This paper presents propagation path loss and outdoor coverage and link budget measurements for frequencies above 6 GHz (mm-wave bands) using directional horn antennas at the transmitter and omnidirectional antennas at the receiver. This work presents measurements showing the propagation time delay spread and path loss as a function of separation distance for different frequencies and antenna pointing angles for many types of real-world environments. The data presented here show that at 28 GHz, 38 GHz and 60 GHz, unobstructed Line of Site (LOS) channels obey free space propagation path loss while non-LOS (NLOS) channels have large multipath delay spreads and can utilize many different pointing angles to provide propagation links. At 60 GHz, there is more path loss and smaller delay spreads. Power delay profiles PDPs were measured at every individual pointing angle for each TX and RX location, and integrating each of the PDPs to obtain received power as a function of pointing angle. The result shows that the mean RMS delay spread varies between 7.2 ns and 74.4 ns for 60 GHz and 28 GHz respectively in NLOS scenario.
Study of user effects on two-port MIMO antennas at 2.4 GHz and 5.8 GHz for Wi...journalBEEI
In this paper, two multiple input multiple output (MIMO) antennas for Wi-Fi/WLAN mobile applications are proposed. The designed two-port MIMO antennas are made up of planar inverted-F antennas (PIFAs). The antenna elements for both designs are symmetrical and placed on the short-edged corners of the substrate used, FR4. The performance of both antennas in the presence of user’s hand is compared in terms of impedance bandwidth and efficiency. An upward shift of up to 0.17 GHz in impedance bandwidth was found for 2.4 GHz and 5.8 GHz antenna. Due to the smaller size of antennas at 5.8 GHz compared to antennas at 2.4 GHz, the antennas are less obstructed by hands and thus the exhibited total efficiency of up to 45.58 % in the presence of human hand. The designed antennas have been fabricated for validation purpose. It is shown that there is a good agreement between simulated and measured results.
Phi shape uwb antenna with band notch characteristicsKiran Ajetrao
In this paper a novel band notch antenna in UWB
frequency range is designed using split rings. Split rings are
overlapped with designed monopole to give phi shape. The slit
gap gives band-notch operation from 5.1GHz to 6.29GHz and
from 4.94GHz to 5.91GHz for SPSSR and SPSCR antennas
respectively. Simulated and measured results are in good
agreement.
Review: Dual Band Microstrip Antennas for Wireless ApplicationsIJAAS Team
In this manuscript, a review of dual band microstrip antennas for wireless communication is presented. This review manuscript discusses regarding the geometric structures, different methods of analysis for antenna characteristics, and different types of wireless applications.
A four-element UWB MIMO antenna using SRRs for application in satellite commu...IJECEIAES
This paper proposes a method for designing a new ultra wide band (UWB) multiple-input multiple-output (MIMO) antenna with two and four elements. First we presented an ultra-wide band antenna we studied these performances. Then, we studied the application of metamaterials to the design of MIMO antennas for miniaturization and the performance of antennas, in order to guarantee the proper functioning of the MIMO system with a much reduced separation distance between the radiating elements (λ/12), where the coupling can be very weak. The application of these circular double ring SRRs materials on the front plan of the antenna has contributed to the increasing of the antenna performance is studied in terms of S-Parameters, efficiency, diversity gain (DG), radiation properties and envelop correlation coefficient (ECC). It offers advantages such as the reduction of weight and congestion that is beneficial for their integration into satellite communications systems.
Design compact microstrap patch antenna with T-shaped 5G applicationjournalBEEI
This paper is presents a microstrap patch with a T-shaped rectangular antenna workings; the T-shaped patch operating at 3.6 GHz resonating frequency range for 5G application (from 2.9 to 4.4 GHz) repectively. The overall size of the proposed antenna is 22×24×0.25 mm3; the feeding technique using a 50 Ω feed line to the antenna. The proposed antenna is printed on compact Rogers RT 588 lz substrate having permittivity (ɛr) 2.00, loss tangent (tan δ) 0.0021, with thikness 0.2 mm. The proposed antenna introducesmany advantages like small size, low profile, and simpler structure. The characteristics such as radiation pattern, reflection coefficient, gain, current distribution, and radiation efficiency are respectively presented and discussed, using CST microwave study in simulating and analysing. Introducing a slot with a rectangular T-shaped patch antenna achieved lower frequency with 98.474% radiation efficiency and peak gain of the proposed antenna at 2.52 dB. The fractional bandwidth is 42.81% (2.90 GHz to 4.48 GHz) with a resonant frequency of 3.6 GHz and return loss at 28.76 dB. This frequency band attributessuited 5 G mobile application.
Cost effective approach for 100 gbps vcsel-mmf lan’seSAT Journals
Abstract VCSELs enable many types of applications, such as optical computing and optical information processing. In this work, firstly different physical parameters Temperature, cavity volume and Bias current have been analysed on VCSEL laser. Further different modulation formats i.e. NRZ, CSRZ and MDRZ are analysed for the first time using VCSEL Laser over GI-MMF in terms of Q-factor and BER.MDRZ comes out to be best modulation formats to prolong the system reach to28Km. Performance analysis of 100 Gbps MIMO system using MDRZ modulation format over 28 km MMF has also been investigated at different distances varied from 8km to 28 km in terms of Q-factor and BER. Keywords: MMF, GI, VCSEL, MDRZ, MIMO
Design Study of a Miniaturized Multi-layered Antenna-in-package for 2.4 GHZ ...IJECEIAES
This paper proposes a novel miniaturization technique to enhance the radiation properties of small multi-layer patch antenna used in packaged circuits. The multilayered antenna design is composed of three layers with different shapes. An enhancement on the radiation properties has been obtained by optimizing the geometry of the radiated element and the parasitic conductor of the middle layer. The whole design has been implemented on the FR4 substrate with dielectric constant of 4.4, thickness of 1.6 mm and Copper thickness of 5 m. The first layer is a driven element while second and the third layer are parasitic patch elements. The optimized multilayer antenna has a very small size of . Considering the small size of the antenna, a detailed study of the parameter affecting the radiation has been considered to force the antenna to operate at 2.4 GHz band. Miniaturization techniques based on the current distribution have been also taken into account to shift down the resonant frequency and reduces more and more the antenna size at the designed operating frequency. The miniaturized antenna maintains performant radiation characteristics in terms of reflexion coefficient, bandwidth and directivity. All developed antennas are simulated using the commercial Electromagnetic CST Microwave Studio software. Achieved results demonstrate a good performance with low cost and compact size
Specific Absorption Rate Assessment of Multiple Microstrip Patch Antenna ArrayTELKOMNIKA JOURNAL
Interaction between electromagnetic field (EMF) radiated from multiple antennas and human body
is crucial to be explored as multiple antennas are the essential implemented devices to achieve the
requirements of the future evolved fifth generation (5G) technology. Thus, this article presents a significant
study of the radiated EMF effect from a single, and multiple antennas towards human through the
assessment of specific absorption rate (SAR). The single antenna, 1 x 2, 1 x 3 and 1 x 4 arrays of
microstrip patch antennas are designed to cover mobile operating frequencies of 0.8, 0.85, 0.9, 1.8, 2.1
and 2.6 GHz. Two types of human head phantoms are implemented in this study, which are specific
anthropomorphic mannequin (SAM) and Voxel head model that placed close to single antenna or antenna
array to investigate the penetration of EMF towards the human tissue. The single antenna or antenna array
is placed with fixed distance of 10 mm from the phantom, which excited by maximum allowable power of
19 dBm in CST Microwave Studio 2016. The effect of the radiated EMF that quantified by SAR parameter,
which depicts satisfying results against the established standard limits at averaged 1g and 10g mass of
tissues for all designated frequencies that utilized for single and multiple antennas.
An Internal Wideband Monopole Antenna for UMTS/WLAN Dual-Mode Mobile PhoneSaou-Wen Su
An internal wideband metal-plate monopole antenna for mobile phone applications is presented. The antenna is easily fabricated by bending a single metal plate and suitable to be embedded within the casing of a mobile phone as an internal antenna. Further, the antenna shows a wide operating bandwidth of about 5 GHz (about 1.8−6.7 GHz), making it easy to cover the UMTS band and the 2.4/5.2/5.8 GHz WLAN bands for mobile/WLAN dual-mode operation for a mobile phone.
Automatic mic adjustment using dc motoreSAT Journals
Abstract
Beamforming theory is used to measure the phase angle between two input signals. Automatic adjustment of height and position of
MIC using dc motors. Horizontal and vertical DC motors are attached with the mic. Microphone array signal processing is to
enhance and extract information carried by acoustic waves received from a number of microphones. Differently placed
microphones are receiving more or less the same signal but with a small time shift. The time delay estimation is calculated using
LabVIEW software.
Keywords - MEMS microphones, beamforming, source localization, DC motor
Microstrip line fed stacked layer e shaped patch antenna for wlanIAEME Publication
The design of stacked layer E-shaped microstrip patch antenna for wideband
operation in the 5-6 GHz frequency range has been presented in this paper. The antenna is
Microstrip line feeded. The Roger RO4350 of 1.6 mm height with relative permittivity of
3.66 and dielectric loss tangent of 0.004 has been used as the substrate on which the patch is
placed. An air box of 2mm height has been introduced between substrate and the ground. The
ANSOFT HFSS software has been used for designing the antenna. High performance
characteristics and good impedance matching have been obtained. The antenna is resonating
at 5.36 GHz with a return loss of -56.5 dB. A maximum gain of 5.3 dB has been obtained in
E-plane. The proposed antenna is suitable for WLAN and WiMax applications operating
within 5.15-5.85 GHz frequency band.
CHARACTERIZATION OF INDOOR PROPAGATION PROPERTIES AND PERFORMANCE EVALUATION ...ijwmn
Indoor wireless systems poses one of the biggest design challenges although it is the most flexible and easily
deployable method of implementing Local Area Networks. This difficulty in predicting the propagation of
radio frequency wave in indoor environments is caused by reflection, refraction, diffraction and scattering
of signals due to closed proximities to furniture, walls, human beings, and reflectors like ceiling, mirrors and
glasses. To help improve the user experience and guarantee good quality of service in indoor situations, the
research investigated the throughput and attenuation effect on signal with respect to 4, 5, 6 and 9 inches sizes
of blocks walls respectively. The characterized Path-loss exponent was 1.999 and differed from the f
Indoor Radio Propagation Model Analysis Wireless Node Distance and Free Space...IJERA Editor
Ultra wide bandwidth (UWB) signals are commonly defined as signals that have a large relative bandwidth
(bandwidth divided by the carrier frequency) or a large absolute bandwidth. Typical indoor environments contain
multiple walls and obstacles consisting of different materials. The RF ultra wideband (UWB) system is a
promising technology for indoor localisation owing to its high bandwidth that permits mitigation of the multipath
identification problem. The work proposed in this paper identifies exact position of transmitter and receiver
wireless nodes, calculates free space path loss and distance between two nodes by considering frequency
bandwidth using 2-point and 3-point Gaussian filter. Also in the paper three types of indoor radio propagation
models are analyzed at ultra wideband frequency range and results are compared to select best suitable model for
setting up indoor wireless connectivity and nodes in typical office, business and college environments and
WPAN applications.
Propagation Path Loss Modeling and Outdoor Coverage Measurements Review in Mi...IJECEIAES
The global bandwidth inadequacy facing wireless carriers has motivated the exploration of the underutilized millimeter wave (mm-wave) frequency spectrum for future broadband cellular communication networks, and mmWave band is one of the promising candidates due to wide spectrum. This paper presents propagation path loss and outdoor coverage and link budget measurements for frequencies above 6 GHz (mm-wave bands) using directional horn antennas at the transmitter and omnidirectional antennas at the receiver. This work presents measurements showing the propagation time delay spread and path loss as a function of separation distance for different frequencies and antenna pointing angles for many types of real-world environments. The data presented here show that at 28 GHz, 38 GHz and 60 GHz, unobstructed Line of Site (LOS) channels obey free space propagation path loss while non-LOS (NLOS) channels have large multipath delay spreads and can utilize many different pointing angles to provide propagation links. At 60 GHz, there is more path loss and smaller delay spreads. Power delay profiles PDPs were measured at every individual pointing angle for each TX and RX location, and integrating each of the PDPs to obtain received power as a function of pointing angle. The result shows that the mean RMS delay spread varies between 7.2 ns and 74.4 ns for 60 GHz and 28 GHz respectively in NLOS scenario.
Human body blockage effect on wireless network performance for outdoor coverageIJECEIAES
The rapid development in the field of communications and growing numbers of the population every year stimulate telecommunications companies to develop communications systems to accommodate all users. In this paper, we will study the blockage effect of the student body on the propagation of the signals in the external wireless network. We took various numbers of the student density on the campus to know the extent it affects especially in crowded environments. The student body structure and buildings are designed in the college according to the real dimensions by Wireless InSite software. We compared scenarios for the different numbers of student density, we noticed that whenever an increase in the student density in the college will lead to increased path loss and delay spread time. In addition, note there is a gradual decrease in the received power (RP) if there is no student density highest RP is -28.2 dBm, when there are 300 students highest RP is -34.7 dBm, and when there are 600 students highest RP is -36.5 dBm. The reasons are that signals path spread inside the college will be passing through several collisions whether student body blockage or buildings that are built from different materials.
International Journal of Business and Management Invention (IJBMI) is an international journal intended for professionals and researchers in all fields of Business and Management. IJBMI publishes research articles and reviews within the whole field Business and Management, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Comparative Study of Path Loss Models for Wireless Communication in Urban and...Onyebuchi nosiri
ABSTRACT: The study was based on the comparative analysis of radio propagation models for Global System for Mobile Communications at 900MHz. Drive test analyses were carried out from two selected terrains in Rivers State namely GRA Phase II and Aggrey Road classified as urban and suburban areas respectively, to evaluate the best propagation model for the study area. The data obtained were used to compare the various prediction models namely; Cost 231, Okumura-Hata and ECC-33. Mean path loss values of 115.16dB for Okumura-Hata and 117.79dB for COST 231 and 280.88dB for ECC-33 respectively were predicted in the urban environment. Mean path loss values of 115.16dB, 114.76dB and 314.84dB were predicted by Okumura-Hata, Cost 231and ECC-33 models respectively in the suburban environment. ECC-33 over estimated path loss and gave the highest prediction in both environments. Okumura-Hata model showed better performance in urban while COST 231 performed better in the suburban environment. Okumura-hata and COST 231 models are recommended for deployment in urban and suburban environments respectively.
Discovering the spatial locations of the radio frequency radiations effects a...IJECEIAES
Nowadays, smart devices have become a major part of human life, and this need has led to an increase in the demand for these devices, prompting major telecommunications companies to compete with each other to acquire the bulk of this market. This competition led to a significant increase in the number of mobile towers, to expand the coverage area. Each communication tower has transmitters and receivers to connect subscribers within the mobile network and other networks. The receivers and transmitters of each mobile tower operate on radio frequency waves. These waves can cause harm to humans if the body tissues absorb the radiation resulting from these waves. Headache, discomfort, and some other diseases are among the effects resulting from the spatial proximity to the mobile towers. In this paper, a model based on geographic information systems (GIS) software is proposed for the purpose of discovering the area of exposure to radio frequency radiation. This model can assists mitigate the opportunities of exposure to these radiations, thus reducing its danger. Real data of the levels of electromagnetic pollution resulting from mobile towers were analyzed during this study and compared with international safety standards.
Channel fading attenuation based on rainfall rate for future 5G wireless com...IJECEIAES
In this paper, the effect of heavy rainfall on the propagation of a 38-GHz in a tropical region was studied and analyzed. Real measurement was collected, with a path length of 300 meters, for a (5G) radio linkage in Malaysia, installed at the Universiti Teknologi Malaysia (UTM) Johor Bahru campus. The employed system entails an Ericsson MINI-Link 38 E-0.6 mm, with a horizontal polarization (HP) antenna at the top integrated with a rain gauge and a data logger. Daily registered samples with a single minute span, for a full study period of 1 month, were collected and evaluated. The obtained rain rate was found as 56 mm/hr with a specific rain attenuation of 18.4 dB/km for 0.01% of the time. In addition to that, a calculated average rain attenuation of 5.5 dB for the transmission path of 300 meters length, was calculated. Based on these findings, a recommendation to update the International Telecommunication Union (ITU) specification of the rain attenuation for Malaysia is proposed. Based on the results, we suggest shifting the zone classification of Malaysia from zone P to zone N-P. Therefore, accurate design for future 5G systems would rely on more precise estimated attenuation levels leading to enhanced performance.
Adaptive 3D ray tracing approach for indoor radio signal prediction at 3.5 GHzIJECEIAES
This paper explained an adaptive ray tracing technique in modelling indoor radio wave propagation. As compared with conventional ray tracing approach, the presented ray tracing approach offers an optimized method to trace the travelling radio signal by introducing flexibility and adaptive features in ray launching algorithm in modelling the radio wave for indoor scenarios. The simulation result was compared with measurements data for verification. By analyzing the results, the proposed adaptive technique showed a better improvement in simulation time, power level and coverage in modelling the radio wave propagation for indoor scenario and may benefit in the development of signal propagation simulators for future technologies.
Unconsidered but influencing interference in unmanned aerial vehicle cabling ...IJECEIAES
The increasing complexity of electrical and electronic systems in unmanned aerial vehicles (UAVs) has raised concerns regarding unwanted electromagnetic interference (EMI) due to limited compartment space. Recent studies have highlighted the UAV cabling as the primary pathway for interference. This paper presents a novel approach to investigating the effects of interference power, polarization angle, and distance from the interference source on EMI in UAV cable systems. Measurements and simulations were performed to analyze the influence of these factors on the radiation received by the cable. A linear dipole antenna, operating at a frequency of 905 MHz, served as the radiation source, while a single wire cable pair terminated with a 50-ohm resistor was employed as the victim. The findings reveal that the power transmitted by the source, the distance between the cable and the source, and the polarization angle have a significant impact on the electromagnetic interference received by the cable. Notably, a perpendicular orientation of the cable to the interference source (antenna) in the far-field yielded a reduction of up to 15 dBm in EMI. The results underscore the necessity for more sophisticated models and comprehensive measurements to fully comprehend the diverse factors affecting polarization losses in practical scenarios.
Signal Strength Evaluation of a 3G Network in Owerri Metropolis Using Path Lo...Onyebuchi nosiri
Abstract: In this work, the path loss and the received signal strength of a 3G network at 2.1GHz was evaluated to determine its performance within the Owerri metropolis. Various measuring equipment such as Transmission Evaluation and Monitoring System (TEMS 11), Global positioning system (BU353 GPS) and laptop were deployed for the drive test within the selected urban and sub-urban regions. From the data collected, Owerri sub-urban region showed poor received signal power level compared to the Owerri urban region. The path loss exponents computed for the Owerri urban and sub-urban regions are 3.24 and 4.34 respectively, the mean square error was evaluated as 1.96 and 1.68. The result obtained showed deviations between the compared existing models (Hata and Cost 231) and the proposed models. However, the slope of the Hata plot was relatively close in comparison to the proposed model than that of Cost 231; hence, the proposed model was best suited for the environment followed by the Hata model.
Signal Strength Evaluation of a 3G Network in Owerri Metropolis Using Path Lo...Onyebuchi nosiri
Abstract: In this work, the path loss and the received signal strength of a 3G network at 2.1GHz was evaluated to determine its performance within the Owerri metropolis. Various measuring equipment such as Transmission Evaluation and Monitoring System (TEMS 11), Global positioning system (BU353 GPS) and laptop were deployed for the drive test within the selected urban and sub-urban regions. From the data collected, Owerri sub-urban region showed poor received signal power level compared to the Owerri urban region. The path loss exponents computed for the Owerri urban and sub-urban regions are 3.24 and 4.34 respectively, the mean square error was evaluated as 1.96 and 1.68. The result obtained showed deviations between the compared existing models (Hata and Cost 231) and the proposed models. However, the slope of the Hata plot was relatively close in comparison to the proposed model than that of Cost 231; hence, the proposed model was best suited for the environment followed by the Hata model.
Performance of modeling wireless networks in realistic environmentCSCJournals
A wireless network is realized by mobile devices which communicate over radio channels. Since, experiments of real life problem with real devices are very difficult, simulation is used very often. Among many other important properties that have to be defined for simulative experiments, the mobility model and the radio propagation model have to be selected carefully. Both have strong impact on the performance of mobile wireless networks, e.g., the performance of routing protocols varies with these models. There are many mobility and radio propagation models proposed in literature. Each of them was developed with different objectives and is not suited for every physical scenario. The radio propagation models used in common wireless network simulators, in general researcher consider simple radio propagation models and neglect obstacles in the propagation environment. In this paper, we study the performance of wireless networks simulation by consider different Radio propagation models with considering obstacles in the propagation environment. In this paper we analyzed the performance of wireless networks by OPNET Modeler .In this paper we quantify the parameters such as throughput, packet received attenuation.
Structure failure often occurs in the structure of wall. This failure can adversely affect the comfort level of the structure. Knowing the behavior of structure resulting from the load is important, as it can help to predict the strength of the structure and comfort of the structure being worked on. One way to find out and predict the strength and comfort of the structure as a result of the load received is experimental test and simulation. The simulation VecTor2 used to predict the shear force, crack, and displacement of reinforced concrete wall when applied the load. This simulation considered the effect of bond stress-slip effect of behavior reinforced concrete. Bonds stress-slip gives a great influence on the strength and hysteretic response of the reinforced concrete wall. That is why this study considers the influence of bond stress-slip on reinforced concrete wall. All the result of simulation VecTor2 using bond stress-slip effect would be compared with the result of the experimental test to see the accuracy of the simulation test.
The concept of sustainable construction is increasingly affecting the development of the construction market.The specificity of construction as an economic activity and ofthe construction product (goods and services) determine the existence of a complex vertical chain of links, involving different actors, who tend to work in the short term and are limited to the rational use of knowledge and experience in practice. Moreover, it is characterized by a low level of inter-company relationshipsresulting in a fragmentation of responsibilityand complicates and hinders the realization of projects and sites,which meet the requirements of sustainable construction. Sustainable construction requires a holistic approach and substantial changes in the organization of construction activity, both at the market and firm level, under the active role of the state. The aim of the study is: 1) analysis of problems in the vertical chain of connections in the construction market, 2)an analysis of the possibilities for creating stable long-term relationships and a joint approach of clients, contractors and subcontractors, which can provide economic, social and environmental efficiency of the construction.
Since the recent development of UAVs(Unmanned Aerial Vehicles) and digital sensors technology has enabled the acquisition of high-resolution image data, it is considered that the image data of riverside can be analysed. Therefore, this study analyses the applicability of remote sensing techniques through image analysis in river systems and habitats. The target stream in this study was the Cheongmi stream and the applicability of the river environmental evaluation technique was analysed through image analysis. The satellite images used for the analysis of river topography and environments were compared with the aerial images taken by a micro UAV), and the river environmental evaluation was carried out with the field research at the same time. The data acquisition range and application limit by river environmental evaluation technique proposed previously were evaluated, and as a result, it was found that it was possible to draw various evaluation parameters using a drone that could take an image at a low altitude in comparison to satellite images.
Industrial engineering is founded on the idea that there is always a better way. This mantra rings true in everything an industrial engineer does, from lean manufacturing to six sigma, to quality control and ergonomics. This paper demonstrates the uniqueness of this discipline, the impact its techniques has in sectors outside of manufacturing, and the positive effects it has on businesses.
The study was carried out using the UAV for analyzing the characteristics of debris in order to present the methodology to estimate the quantitative amount of debris caught in small river facilities. A total of six small rivers that maintained the form of a natural river were selected for collecting UAV images, and the grouping of each target in the image was carried out using the object-based classification method, and based on the object-based classification result of the UAV images, the land cover classification for the status of factors causing the generation of debris for six target sections was carried out by applying the screen digitizing method. In addition, in order to verify the accuracy of the classification result, the error matrix was performed, securing the reliability of the result. The accuracy analysis result showed that for all six target sections, the overall accuracy was 93.95% and the Kappa coefficient was 0.93, showing an excellent result.
Multilevel Inverters are getting popular and have become more attractive to researchers in the recent times for high power applications due to their better power quality and higher efficiency as compared to two level inverters. This research work presents a detailed comparative analysis of various multicarrier sinusoidal PWM schemes such as In Phase Disposition, Phase Opposition Disposition and Alternate Phase Opposite Disposition implemented on five level conventional and modified cascaded h-bridge inverters in MATLAB/SIMULINK software. Conventional five level topology uses eight switches and suffers from increased switching complexity while modified five level topology uses only five switches and is recommended to reduce switching complexity and switching losses. It also ensures less number of components, reduced size and overall cost of the system. The effect of modulation index (Ma) on the output harmonic contents in various PWM techniques is also analyzed.
Objective: Cervical cancer (CC) is one of the leading causes of cancer-related deaths among women worldwide.Human papillomavirus (HPV) is the most important element in this disease.The aim of this study is to prepare TiO2/ZnO nanocomposite (NC), titanium dioxide (TiO2) and zinc oxide (ZnO)nanoparticles (NPs) to determine the anticancer activity on human CC cell line (HeLa) and healthy mouse fibroblast cell line (L-929). Materials&Methods: ZnO, TiO2 NPs and NC were prepared by a solution combustion synthesis method. The samples were characterized by ultraviolet–visible spectroscopy. Stability analysis was performed with zeta potential. The synthesized NC and NPs were permormed to the HeLa and L-929 cell lines and anticancer activity of these NC and NPs were determined by using MTT method. The HeLa and L-929 cells were treated with different concentrations of these NC and NPs (0,5-100 μg/ml) for 24, 48 and 72 hours. The spectrophotometric readings at 570 nm were recorded and analysed with Graphpad Prism7. Results: NC and NPs were successfully synthesized. The effects of these NC and NPs on the HeLa and L-929 cells were compared with the control group and IC50 values were determined for 24, 48 and 72 hours. Then we compared the effects of these molecules on the L-929 cell line with the HeLa cell line and founded more active is on HeLa cells. Conclusion:There are many drugs used in CC treatment. However, undesirable toxicity and drug resistance of these drugs negatively affect treatment.We have synthesized NC and NPs in order to formulate basis of a new drug in this study and have identified anti-cancer activity.As a result, we found that NC and NPs anti-cancer activity was higher in HeLa cells than in L-929.
Graphene is a material that attracts attention in technical textile applications as in many other areas due to its outstanding features. In this study, it was aimed to investigate the performance properties of graphene coated fabrics. Pre-treated polyester fabrics were coated with nano-graphene powders at different concentration rates (50, 100 and 200 g/kg) by knife-over-roll technique. According to test results, generally, the graphene coating had a positive effect on the performance properties of polyester fabrics.
This study was focused on the effects of Sugarcane Bagasse Ash (SCBA) additive on process parameters and compost quality of Co-composting of filter cake and bagasse. Filter cake and bagasse were mixed and sugar cane bagasse ash (SCBA) from a heating power plant of sugar mill. Three compost mixes (M) were obtained: MA with 0%, MB with 10% and MC with 20 wt % of fuel ash. These three different mixes were composted in an experimental composter as three parallel experiments for 3 weeks each. The physical, chemical and biological parameters were monitoring during composting. Significantly, ash additives decreased the total organic carbon; measured by mineralization the breaking down of the organic matter was more rapid in the MC than in the MA, as well as increased the pH during composting. Interesting, the pH decreased was most important in MA and attend 5 for the first week of composting, and then it gradually increased to pH around 8 at the end of the process. The results indicated that ash inhibits the pH drop due to production of organic acids during composting. The acidity of the material was reported as affects the process during the initial phase of rising temperature and quality of the final product. The temperature reached up to 50-55oC during thermophilic phase, the greater temperature was obtained for MC. At the end of composting, the electrical conductivity increased in the MC, especially in MC, but don’t exceed limit (4 mS/cm) for prevent phytotoxicity of the compost. The SCBA additive was likely to speed up the composting process of bagasse with filter cake from 44 days to 33 days.
The work presents report on production and analysis of bioresin from epoxidized mango kernel oil (EMKO). The bioresin (acrylated epoxidized mango kernel oil) or AEMKO was produced from epoxidized mango kernel oil via acrylation chemical reaction route. The FTIR spectrum analysis of epoxidized mango kernel oil (EMKO) and acrylated epoxidized mango kernel oil (AEMKO) produced gave the degree of acrylation (DOA) as 46%. The Viscosity of AEMKO (resin) was determined at room temperature (25 °C) to be 387cP while the density at 25oC was 1.2 g/cm3. The glass transition temperature (Tg) of the bioresin was determined to be 95oC. Production cost analysis of the bioresin was done and found to be N8, 804.35 per litre. The high cost was due to high costs of the chemicals, labour and overhead charges involved at my local level. At commercial level, those components of the costs would definitely reduce to the level compatible with synthetic (polyester) resin (N2, 500 per litre) currently sold by some markers in Nigeria. However, the overall results of the work demonstrated that bioresin can be successfully synthesized from mango kernel oil with properties compatible with ASTM standards. The commercial production of the bioresin will go a long way in mitigating some of the challenges associated with total use of fossil fuel currently use for production of bulk of synthetic resins for composite manufacturing activities.
The window functions used for digital filter design are used to eliminate oscillations in
the FIR (Finite Impulse Response) filter design. In this work, the use of Particle Swarm Optimization
(PSO) algorithm is proposed in the design of cosh window function, in which has widely used in the
literature and has useful spectral parameters. The cosh window is a window function derived from the
Kaiser window. It is more advantageous than the Kaiser window because there is no power series
expansion in the time domain representation. The designed window function shows better ripple ratio
characteristics than other window functions commonly used in the literature. The results obtained
were presented in tables and figures and successful results were obtained
The aim of the study was to investigate the relationship between 2D gray scale pixels and 3D gray scale pixels of image reconstructions in computed tomography (CT). The 3D space image reconstruction from data projection was a challenging and difficult research problem. The image was normally reconstructed from the 2D data from CT data projection. In this descriptive study, a synthetics 3D Shepp-Logan phantom was used to simulate the actual data projection from a CT scanner. Real-time data projection of a human abdomen was also included in this study. Additionally, the Graphical User Interface (GUI) for the application was designed using Matlab Graphical User Interface Development Environment (GUIDE). The application was able to reconstruct 2D and 3D images in their respective spaces successfully.The image reconstruction for CT in 3D space was analyzedalong with 2D space in order to show their relationships and shared properties for the purpose of constructing these images.
In this work the antimicrobial activity and the economic viability analysis of the essential oil extracted from the hybrid formed by the seeds species of the Murupi (Capsicum chinense), Criollos de Morellos (Capsicum annuum) and Finger of the young (Capsicum baccatum ). The essential oil of the pepper was obtained by the steam drag process and for this extraction, the Soxhlet method was used. For the determination of the antimicrobial activity of the oil the disc diffusion method was used for the strains of Bacillus cereus, Staphylococcus aureus and Escherichia coli. The results point out the resistance of the tested strains to the essential oil of the respective pepper and, in terms of financial and economic aspects, this was not feasible on a small scale. It is suggested that other microorganisms be tested and, later, that studies be carried out with the purpose of characterizing the studied oil chemically for proper application in the agroindustry.
Eliminating Gibbs phenomenon, which occurs during design of Finite Impulse Response (FIR) digital filter and which is undesirable, is very important in order to provide expected performance from digital filter. Window functions have been developed to eliminate these oscillations and to improve the performance of the filter in this regard. In this work, an application was developed for designing window function using LABVIEW which is a graphical programming environment produced by National Instruments. LABVIEW offers a powerful programming environment away from complexity. In this work, the performances of cosh and exponential window functions, which are designed by using the possibilities of LABVIEW in programming, are examined and the situations that will occur under various conditions are compared.
Better efficiency of the air transport system of a country at the national level, especially in terms of its
capacity to generate value for passenger flow and cargo transport, effectively depends on the identification of
the demand generation potential of each hub for this type of service. This requires the mapping of the passenger
flow and volume of cargo transport of each region served by the system and the number of connections. The
main goal of this study was to identify important factors that account for the great variability (demand) of
regional hubsof the airport modal system in operation in the State of São Paulo, the most populated and
industrialized in the Southeast region in Brazil. For this purpose, datasets for each airport related to passengers
or cargo flow were obtained from time series data in the period ranging from January 01, 2008 to December
31, 2014. Different data analysis approaches could imply in better mapping of the flow of the air modal system
from the evaluation of some factors related to operations/volume. Therefore, different statistical models - such
as multiple linear regression with normal errors and new stochastic volatility (SV) models - are introduced in
this study, to provide a better view of the operation system in the four main regional hubs, within a large group
of 32 airports reported in the dataset.
Linear attenuation coefficient (휇) is a measure of the ability of a medium to diffuse and absorb radiation. In the interaction of radiation with matter, the linear absorption coefficient plays an important role because during the passage of radiation through a medium, its absorption depends on the wavelength of the radiation and the thickness and nature of the medium. Experiments to determine linear absorption coefficient for Lead, Copper and Aluminum were carried out in air. The result showed that linear absorption Coefficient for Lead is 0.545cm – 1, Copper is 0.139cm-1 and Aluminum is 0.271cm-1 using gamma-rays. The results agree with standard values.
This study presents results of Activity Concentrations, Absorbed dose rate and the Annual Effective dose rates of naturally occurring radionuclides (40K, 232Th and 226Ra) absorbed in 8 soil samples collected from different areas within the Ajiwei mining sites in Niger State, North Central Nigeria. A laboratory γ-ray spectrometry NaI (Tl) at the Centre for Energy Research and Training (CERT), Ahmadu Bello University Zaria, was used to carry out the analysis of the soil samples. The values of Activity Concentration for 40K ranged from 421.6174 ± 7.9316 to 768.7403 ± 7.9315; for 226Ra it ranged from 20.6257 ± 2.0858 to 44.0324 ± 5.0985 and for 232Th the ranged is from 23.7172 ± 1.3683 to 62.7137 ± 4.1049 Bq.Kg-1. While the Absorbed Dose for 40K ranged from 17.5814 ± 0.3307 to 32.0565 ± 0.3307 ŋGy.h-1, for 226Ra the range is from 9.5291 ± 0.9636 to 20.3430 ± 2.3555 ŋGy.h-1 and for 232Th range from 14.3252 ± 0.4414 to 37.8791 ± 2.4794 ŋGy.h-1. The total average Absorbed Dose rate of the 8 soil samples collected is 63.7877 ŋGy.h-1 and the estimated Annual Effective Dose for the sampled areas range from 0.0636- 0.1028mSvy-1 (i.e 64 – 103 μSv.y-1), with an average Annual Effective Dose of 0.0782 mSv.y-1 (i.e. 78.2 μSv.y-1). These results show’s that the radiation exposure level reaching members of the public in the study areas is lower than the recommended limit value of 1 mSv.y-1 (UNSCEAR, 2000). Also the mean Radium Equivalents obtained ranged from 107.3259 BqKg-1 (AJ1) to 179.4064 BqKg-1 (AJ4). These results show that the recommended Radium Equivalent Concentration is ≤ 370 BqKg-1 which is the requirement for soil materials to be used for dwellings, this implies that the soil from this site is suitable use for residential buildings. The mean External Hazard Index ( Hext ) ranged from 0.1229 Bqkg-1 (AJ3) to 0.4226 Bqkg-1 (AJ7).. While the maximum allowed value of (Hext = 1) corresponds to the upper limit of Raeq (370 BqKg-1) in order to limit the external gamma radiation dose from the soil materials to 1.5 mGy y-1. That is, this Index should be equal to or less than unity (Hext ≤ = 1). Furthermore, the mean Internal Hazard Index (Hext) ranged from 0.3456 Bqkg-1 (AJ1) to 0.6453 Bqkg-1 (AJ2) .Finally, the mean value of the Excess Alpha Radiation (Iα) ranged from 0.1031 Bq.Kg-1 (AJ1) to 0.2202 Bq.Kg-1 (AJ3. All these values for Iα are below the maximum permissible value of Iα= 1 which corresponds to 200 Bq.Kg-1. It can therefore be said that no radiological hazard is envisaged to dwellers of the study areas and the miners working on those sites area.
Pick and place task is one among the most important tasks in industrial field handled by “Selective
Compliance Assembly Robot Arm” (SCARA). Repeatability with high-speed movement in horizontal plane is
remarkable feature of this type of manipulator. The challenge of design SCARA is the difficulty of achieving
stability of high-speed movement with long length of links. Shorter links arm can move more stable. This
condition made the links should be considered restrict then followed by restriction of operation area
(workspace). In this research, authors demonstrated on expanding SCARA robot’s workspace in horizontal area
via linear sliding actuator that embedded to base link of the robot arm. With one additional prismatic joint the
previous robot manipulator with 3 degree of freedom (3-DOF), 2 revolute joints and 1 prismatic joint is become
4-DOF PRRP manipulator. This designation increased workspace of robot from 0.5698m2 performed by the
previous arm (without linear actuator) to 1.1281m2 by the propose arm (with linear actuator). The increasing
rate was about 97.97% of workspace with the same links length. The result of experimentation also indicated
that the operation time spent to reach object position was also reduced.
The paper contains several technical solutions of air and moisture permeability in textile
layers and theirs combinations. It is useful collection of the author’s knowledge from several last years.
Discussed are also various marketing declarations of miraculous characteristics of individual used materials.
Examples show not only own technical solution, but also the good description of ongoing processes, using the
method of numerical simulation.
Physical and chemical properties of host environment to concrete structures have serious impact on
the performance and durability of constructed concrete facilities. This paper presents a 7-month study that
simulated the influence of soil contamination due to organic abattoir waste and indiscriminate disposal of spent
hydrocarbon on strength and durability of embedded concrete. Concrete mix, 1:1.5:3 was designed for all cube
and beam specimens with water-cement ratio of 0.5 and the compressive and flexural strengths of the specimen
were measured from age 28 days up to 196 days in the host environment. It was found that both host
environments attack the physical and strength of concrete in compression and flexure. However, hydrocarbon
had much greater adverse effect on the load-carrying capacity of concrete structures and hence make
constructed facilities less serviceable and vulnerable to premature failure.
More from International Journal of Modern Research in Engineering and Technology (20)
Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
Also when the user tries to sale items which are not in stock, the system will prompt the user that the stock is not enough. Customers of this system can search for a automobile; can purchase a automobile easily by selecting fast. On the other hand the stock of automobiles can be maintained perfectly by the automobile shop manager overcoming the drawbacks of existing system.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
The A318, A319, A320 and A321 are twin-engine subsonic medium range aircraft.
The family offers a choice of engines
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
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This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
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Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
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ExperimentalPropagationStudyfor 2G, 3G, and 4G Frequencies
1. International Journal of Modern Research in Engineering and Technology (IJMRET)
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w w w . i j m r e t . o r g I S S N : 2 4 5 6 - 5 6 2 8 Page 20
ExperimentalPropagationStudyfor 2G, 3G, and 4G
Frequencies
Fulya Callialp Kunter1,2
, Saban Selim Seker3
, Elif Surmeli3
, Osman Cerezci4
1
(ElectricalandElectronicsEngineeringDepartment, Marmara University, Turkey)
2
(ElectricalEngineeringDepartment, ChulalongkornUniversity, Thailand (on sabbaticalleave))
3
(ElectricalandElectronicsEngineeringDepartment, BogaziciUniversity, Turkey)
4
(ElectricalandElectronicsEngineeringDepartment, Sakarya University, Turkey)
ABSTRACT : Nowadays, there has been an increase and dependent items that affect the quality of the signals
such as the properties of substances in the buildings, objects and humans’ movements, electronic equipment. In
this study, the effects of electromagnetic interference on the functional usage of mobile communications are
examined. The indoor and outdoor attenuation characteristics of 2G, 3G and 4G frequency bands are
investigated. Field strength measurements are conducted in university campusopenarea, along a corridorfield
in a fivestoreyuniversitybuilding, in different floors, and rooms, where normal incidence on plane boundary is of
main concern. This study investigates multilayer model for building structures. The evaluation of measured
values together with the simulated results is compared with literature outcomes. In addition, dependency with
the frequency, power of the waves and existence of trees on the transmission path are also discussed.
KEYWORDS -Attenuationcharacteristics, electromagneticpropagation,
fieldstrengthmeasurement,transmissionpath.
I. INTRODUCTION
Thegreatsuccess of mobile
communications encouraged the researchers to
study, either statistical or theoretical, on the indoor
radio propagation, which was shown to be very
complex and dependent on variousfactors,
whichcauseinterference, attenuationandfluctuations
in signalstrength [1-7]. Investigation of indoor
propagation characteristics cover many situations
in which they differ in the properties of
construction materials, moving individuals,
furnishings, architectural configurations etc.
Therefore in order to provide services with good
coverage and efficiency, the characteristics of
indoor propagation for mobile communication must
be investigated in different environments and
conditions. For instance in the healthcare domain,
the increase in the use of cellular developments
prompt the researchers concern about the
interference problems. Many studies reveal that
2G/3G/4G LTE cellular phones exposures effects
the function and operation of medical devices [8-
17]. In these publications they find out that the
clear distinction between 2G , 3G and 4G cellular
phones is that the peak power emitted by 3G and
4G cellular phones are much lower ( max. 1 W)
compared to the corresponding value issued by the
2G phones.
Propagationprediction has been an
important subject for the design of mobile
communications systems. In order to provide
efficient and reliable coverage of services,
understanding the factors that influence signal
strength and determining the parameters of radio
system is very important. ElgannasandKostanic
[18] have studied the propagation characteristics
for both indoors and outdoors at 850 MHz and
1900 MHz frequencies. The penetration loss of
four different buildings are examined and
concluded that building penetration loss may not be
depend on the operating frequency. Evaluation and
analysis of 3G network in Lagos, Nigeria has
beenconductedbyAkinyemi et al. [19].
Receivedsignalcodepower, Ec/No service quality,
speechqualityindex, transmittingpower and path
loss are the parameters measured in the study. In
2016, RodriquezLarrad [20]
analysisexploredthepenetration loss at normal
incidence for the frequency range from 800 MHz
up to 18 GHz for several modern constructions in
comparison with an old building. From the
measurement results, it is observed that the
attenuation experienced in all the different
scenarios is material dependent. A set of
dedicatedmeasurementswereperformed along
several corridors in shopping malls and modern and
old constructions in order to characterize the
2. International Journal of Modern Research in Engineering and Technology (IJMRET)
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different indoor propagation contributions. The
attenuation from the indoor walls was found to
present very small frequency dependence.
Subsequent studies showed that not only
the existence of floors or the distance between the
receiver and transmitter but also the existence of
obstacles, features of construction materials,
architectural configurations and many other factors
had significant influence the path loss [7]. For this
reason path loss models [21] have been modified
multiple times and propagation parameters have
been improved according to measurement data.
Hence approximate numerical approaches based on
theory have been of interest. In particular, ray
tracing, which is a nice method for calculating
radio signal strength, propagation parameters in an
indoor environment, is based on Fresnel equations
and uniform/general theory of diffraction. Inyears,
manydifferent ray-
tracingapproacheshavebeendevelopedformodelingi
ndoorwavepropagationandpenetration [3, 22].
Numerous studies include comparisons
between the path losses from propagation
measurements at various frequencies indoors and
outdoors [5], however an extensive experimental
propagation study on building structures for 2G,
3G and 4G frequencies have not been reported yet.
This study presented in this paper describes
detailed measurement conducted inside the
university building and outside the building to
characterize the propagation at 2G, 3G and 4G
frequencies. This paper is organized as follows.
The first step of the study addresses the locations
where the experiments have been conducted. In the
initial part of the study, the transmitter and the
receiver configurations with the transmitter power
is given for each setup areas at selected
frequencies. Next section highlights the
experiments which are conducted to provide the
indoor and outdoor attenuation characteristics. In
the conclusion, further analyses are given in details
by means of simulations, and the future potential
research directions that could help to extend the
presented findings are introduced.
II. EXPERİMANTALSETUPAREAS
Each floor has 2.70 m height and 1.35 m
concrete wall between floors. Transmitter was
placed 2.4 m above the ground and receiver was
held at 0.2 to 1.20 m above the floor. The ceiling
has spot lightening and measurements were made
close to the staircase. The measurements were
performed outdoor and at different points in
thecorridors, at differentfloorsanddifferentrooms in
theBogaziciUniversity KB building. In each
measurements, transmitter power was 2 W
withpulsesignal,
andthetransmitterfrequencywas900/2100/2450
MHz.
Freespacemeasurementsweremade in
BogaziciUniversity North Campus in front of
Abtullah Kuran library. The transmitter was placed
1.50 m above the ground and the receiver was held
at 1.30 m height during experiment. Receiver was
moved along the straight path with 3m
displacement at each measurement. The panel
antenna was vertically polarized and the receiver
was an isotropic three axis antenna.
In the corridor, the transmitter was placed
1.20 m above the ground and the receiver was held
at 1.2 m height during experiment.
Through floors, the transmitter was placed
2.40 m facing the ceiling. Receiver was held at
points that were in the direction transmitter
propagation.
Transmitter in the room measurements
was placed on the desk and transmitter antenna 20
cm above the surface, 1.20 m above the ground.
Thetransmittingantenna has 7±1 dBigainfor 900
MHz and 8 ±1 dBigainfor 2100 MHz and 2450
MHz. The transmitting antenna is a directional
panel antenna which is vertically polarized and has
dimensions 0.21 m x 0.18 m x 0.44 m.
Thereceiverwiththree-axisantenna has gain 18.90
dBi, 13.8dBiand 15.5 dBifor 900 MHz, 2100 MHz
and 2450 MHz respectively. It was held at 1.2 m
height during measurements.
III. EXPERİMENTALINVESTİGATİON
3.1 Freespacepropagationresults
This model is based on Friisformula,
whichgives the amount of power of an antenna
which is received under ideal conditions from
another antenna. This equation provides accurate
results for far field, unobstructed free space and
correct alignment and polarization of antennas.
Plane earth model takes into account the
near ground effects in propagation and loss due to
reflection from earth and other propagation
mechanisms are included. The parameters can be
defined empirically from the best fit to data [23].
3. International Journal of Modern Research in Engineering and Technology (IJMRET)
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Figure 1. Attenuation(dB) vs. distance from
transmitter in open area for 900 MHz
Figure 2. Attenuation(dB) vs. distance from
transmitter in open area for 2100 MHz
Figure 3. Attenuation(dB) vs.
distancefromtransmitter in openareafor 2450 MHz
It is clear from the results that the ground
effect shows itself after a certain distance and
dominates the free space attenuation. When, the
distance is small enough, the reflected signal
cannot contribute to the measured signal. Finally
the movement of people also might have caused the
deviations in signal temporarily.
3.2 Corridorattenuation
Figure 4. Attenuation(dB) vs. distance from
transmitter along the corridor for 900 MHz
Figure 5. Attenuation(dB ) vs. distance from
transmitter along the corridor for 2100 MHz
4. International Journal of Modern Research in Engineering and Technology (IJMRET)
www.ijmret.org Volume 3 Issue 2 ǁ February 2018.
w w w . i j m r e t . o r g I S S N : 2 4 5 6 - 5 6 2 8 Page 23
Figure 6. Attenuation(dB) vs.
distancefromtransmitteralongthecorridorfor 2450
MHz
The results have shown that for the
attenuation in corridors, the reflection from the
floor affects the propagation after a certain distance
which can be calculated from ground model. The
deviations from theoretical and empirical results
are due to the effect of opendoornearthetransmitter,
thematerial of floor, theworkingWiFitransmitter on
thewall. Moreover diffraction plays a role in
saturation of signals after a certain distance from
the transmitter. Hence the attenuation at the same
distance is less than free space attenuation.
3.3 Floors
EM waves impinge upon a plane boundary
obliquely will be partially reflected back to first
medium and partially transmitted (refracted) in the
second medium. Boundary conditions determine
the direction of propagation and the amplitudes of
these waves. The path loss in terms of reflection
and transmission coefficients is calculated for TE
polarization [2].
Commonbuildingmaterialsare non-
magnetic and non-ionised so that only the dielectric
properties of building materials will be considered.
Mostbuildingmaterialsshowlossydielectriccharacter
istics. Hence the wave impedance and the
reflection/transmission coefficients include
imaginary parts. We have calculated these
coefficients referring the permittivity studies of
building construction materials.
Moreoveraccordingtothisattenuationperwallvaluew
ehavemodifiedtheFriisequationand in
thefiguresbelowthevalueforFriisvaluesare not
thepurefreespaceloss.
It can be seen that the free space formula
with wall loss may not be inadequate to predict
attenuation, due to existing a lot of environmental
factors that contribute to signal level.
Figure 7. Attenuation(dB) vs. distance from
transmitter on the floor for 900 MHz
Figure 8. Attenuation(dB) vs. distance from
transmitter on the floor for 2100 MHz
Figure 9. Attenuation(dB) vs. distance from
transmitter on the floor for 2450 MHz
Measurements in different floors have
shown that the effect of multipath components
might affect the signal strength and coverage in the
area strongly. Signals find new paths to propagate
upper floors which cause less decrement through
upper floors. Literature coincides with our results.
ITU model is used for simulation. The results are
quite similar with measurement data.
5. International Journal of Modern Research in Engineering and Technology (IJMRET)
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ITU model for attenuation in indoor
environment includes different parameters which
are tabulated for different frequencies. The ITU
formulas are stated in [24, 25].
It is
importanttonotethatthetransmittingWiFidevices in
eachfloorcausedgreatinterference effect and
resulted in divergence from theoretical and
empirical expected values. Moreover the ceiling
material and lightening caused reflections and
variations in signal strength.
3.4 Rooms
WehavemodifiedtheFriisequationbyadding
a wall loss component in the equation and the
graphs are plotted according to these values.
Hencethefriisvalues in thegraphsincludeattenuation
by walls. Moreover the same formula for the
corridors, the ITU model is used for simulating the
data.
Figure 10. Attenuation(dB) vs.
distancefromtransmitter in theroomfor 900 MHz
Figure 11. Attenuation(dB) vs. distance from
transmitter in the room for 2100 MHz
Figure 12. Attenuation(dB) vs. distance from
transmitter in the room for 2450 MHz
Theresultsfromfiguresshowthattheempiric
almodificationtoFriisequationimprovesthepredictio
n of propagation and gives closer results to
measurement data. The differences between the
measured data and the models are caused by the
metallic book shelves, the boards on the walls and
other furniture as obstructions. It can easily be seen
that as the power is getting higher, the signal
strength is more deviating. Moreover, rise in
frequency is positively correlated with loss through
obstacles; in addition diffracted signals contribute
less to the received power. On the contrary, leading
to lower loss, the Fresnel region is limited
obstructed at higher frequencies. However, the
genuine path loss is counted on these opposing
mechanisms.
IV. CONCLUSİON
The results in our experiment mostly
comply with EM wave theory. The outcomes of the
project can be discussed as follows:
1-Free space measurements have shown
that transmitter must be placed high enough in
order to reduce and avoid earth effect on signal
strength. It can be also seen that measured values
converge to plane earth model values after a
distance and this threshold is determined by heights
of the transmitter, receiver and frequency of signal
[2].
2-Measurements along the corridor have
shown that again in order to reduce reflection from
the ground the transmitter must be placed high
enough, actually it is recommended to place the
transmitter antenna as close as possible to ceiling in
order to assure LOS propagation [24].
6. International Journal of Modern Research in Engineering and Technology (IJMRET)
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3-In different floors an analysis based on
electromagnetic (EM) wave theory would be very
complex, since the multipath phenomena cause
variations and emergence of signals in unexpected
points. However basically, the attenuation is due to
material separating the floors and adding the
attenuation due to wall transmission and free space
loss gives quite good results. In different floors
measurements for 900 and 2100 MHz
gavereasonableoutcomes, whereas 2450 MHz
signalstrengthsometimesincreaseduetoWiFitransmit
ters at eachfloornearmeasurement point. Moreover
the lightening spots on the ceiling effects the
attenuation with 15-30 dB magnitude.
4-Measurements in rooms have shown
that the effect of the furniture, electrical properties
of materials, dimensions of building structures
[25]. This indicates that diffractions and reflections
may vary the signal strength dramatically.
The theoretical or empirical results are not
the same as the measurements due to
environmental conditions. Moreover different
factors that affect measured signal level have also
been investigated. It is reported that the user’s head
and body affect the received signal level. In future
the measurement data may be used for
characterization studies of building materials,
investigation of compliance with electromagnetic
safety rules, design of local area networks and
communication systems. Furthermore a new
empirical prediction model based on the
measurement data can be developedandused in
ordertoimprovecoverage of WiFi, etc.
V. Acknowledgements
Thiswork is
supportedbyBogaziciUniversityResearch
Foundation projectcode: 9860 and by Marmara
University Research Project code: FEN-A-120514-
0157.
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[18] H. Elgannas, I. Kostanic, OutdoortoIndoor propagation
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