1) The document describes the design of compact range feeds intended to achieve low cross-polarization measurements (below -40 dB) across a wide frequency band and angular range.
2) The feeds use a corrugated circular aperture design with stepped rings to widen the beamwidth. They are designed to cover frequencies from 1.1 to 40 GHz using interchangeable aperture sections for different sub-bands.
3) Measurements and CHAMP simulations show the feeds achieve cross-polarization levels below -43 dB over a 40-degree cone as required for high-accuracy compact range measurements. A technique for correcting measured data for the polarization ratio of the source antenna is presented.
A cellular base station antenna configuration for variable coverageIJECEIAES
The field coverage offered by the base station antenna in GSM systems influences the reception and interference performances. The coverage can be varied by scanning the mainbeam direction or varying the shape of the radiation pattern. In cellular system applications, a simple technique is desirable to achieve this goal. A simple technique to vary the coverage of cellular base station is investigated. The technique uses two conventional antennas tilted by a certain angle and fed by the same signal but at variable amplitudes. It is demonstrated that the field across one half of the covered sector can be gradually increased while that at the other half is reduced by varying the excitations of the two antenna elements. This can be deployed in a simple electronic means in response to the changing scenario rather readjusting the direction of the base station antenna.
Four-Element Triangular Wideband Dielectric Resonator Antenna excited by a Co...IOSR Journals
Abstract-This paper numerically examines an array of four dielectric resonant antenna of equilateral triangle
shape. The Structure provides wideband low profile monopole-like antenna. As much as 30.90 % matching
bandwidth (S11<-10 dB) with monopole-like radiation pattern over the entire band has been achieved with 6.357
dBi peak gain. The geometry is a four equilateral triangular dielectric volume over a ground plane, and is
centrally excited by a coaxial probe to provide a broadside radiation pattern. An approximate expression is
used to compute the resonance frequency. Results are simulated using CST (Computer Simulation Technology)
Microwave Studio Suite 10.
Keywords-Dielectric resonator (DR), triangular dielectric resonator antenna (TDRA), S11 (S-Parameter),
perfect conductor (PEC), Impedance Bandwidth (IBW).
Numerical Simulation of Highly-Nonlinear Dispersion-Shifted Fiber Optical Par...TELKOMNIKA JOURNAL
The previous study investigated the fiber parameters on the analytical one-pump fiber optical parametric
amplifier (FOPA) gain spectrum of a loss-free highly-nonlinear dispersion-shifted fiber (HNL-DSF) and
got the optimum results for each parameter. However, the FOPA gain of the combination of all the optimum
values of the considered parameters was not reported. Hence, this paper intends to investigate the analytical
FOPA gain of the combination of all the optimum values of the considered parameters from the previous
study. Later, the analytical gain was compared with the numerical gain from the fourth-order Runge-Kutta
(RK4) method and Matlab built-in function, ode45. Next, the effect of fiber loss and higher order dispersion
coefficients such as fourth and sixth-order dispersion coefficients were studied. It is found that RK4 gives
a smaller error and the gain reduces while the bandwidth remains same in presence of fiber loss. The
fourth-order dispersion coefficient broadens the bandwidth a bit while maintaining the gain and there are two
narrow-band gains generated to the left and right-side of the broad-band gain. The sixth-order dispersion
coefficient just shifts the two narrow-band gains toward or away from the broadband gain depending on the
positive or negative signs of the sixth-order dispersion coefficient.
A cellular base station antenna configuration for variable coverageIJECEIAES
The field coverage offered by the base station antenna in GSM systems influences the reception and interference performances. The coverage can be varied by scanning the mainbeam direction or varying the shape of the radiation pattern. In cellular system applications, a simple technique is desirable to achieve this goal. A simple technique to vary the coverage of cellular base station is investigated. The technique uses two conventional antennas tilted by a certain angle and fed by the same signal but at variable amplitudes. It is demonstrated that the field across one half of the covered sector can be gradually increased while that at the other half is reduced by varying the excitations of the two antenna elements. This can be deployed in a simple electronic means in response to the changing scenario rather readjusting the direction of the base station antenna.
Four-Element Triangular Wideband Dielectric Resonator Antenna excited by a Co...IOSR Journals
Abstract-This paper numerically examines an array of four dielectric resonant antenna of equilateral triangle
shape. The Structure provides wideband low profile monopole-like antenna. As much as 30.90 % matching
bandwidth (S11<-10 dB) with monopole-like radiation pattern over the entire band has been achieved with 6.357
dBi peak gain. The geometry is a four equilateral triangular dielectric volume over a ground plane, and is
centrally excited by a coaxial probe to provide a broadside radiation pattern. An approximate expression is
used to compute the resonance frequency. Results are simulated using CST (Computer Simulation Technology)
Microwave Studio Suite 10.
Keywords-Dielectric resonator (DR), triangular dielectric resonator antenna (TDRA), S11 (S-Parameter),
perfect conductor (PEC), Impedance Bandwidth (IBW).
Numerical Simulation of Highly-Nonlinear Dispersion-Shifted Fiber Optical Par...TELKOMNIKA JOURNAL
The previous study investigated the fiber parameters on the analytical one-pump fiber optical parametric
amplifier (FOPA) gain spectrum of a loss-free highly-nonlinear dispersion-shifted fiber (HNL-DSF) and
got the optimum results for each parameter. However, the FOPA gain of the combination of all the optimum
values of the considered parameters was not reported. Hence, this paper intends to investigate the analytical
FOPA gain of the combination of all the optimum values of the considered parameters from the previous
study. Later, the analytical gain was compared with the numerical gain from the fourth-order Runge-Kutta
(RK4) method and Matlab built-in function, ode45. Next, the effect of fiber loss and higher order dispersion
coefficients such as fourth and sixth-order dispersion coefficients were studied. It is found that RK4 gives
a smaller error and the gain reduces while the bandwidth remains same in presence of fiber loss. The
fourth-order dispersion coefficient broadens the bandwidth a bit while maintaining the gain and there are two
narrow-band gains generated to the left and right-side of the broad-band gain. The sixth-order dispersion
coefficient just shifts the two narrow-band gains toward or away from the broadband gain depending on the
positive or negative signs of the sixth-order dispersion coefficient.
Design and development of aperture coupled rectangular microstrip antenna for...eSAT Journals
Abstract This paper presents the experimental investigations carried out for obtaining wide band operation of rectangular microstrip antenna by using aperture coupled feeding technique. By incorporating U-slots with stubs on the radiating element, antenna resonates for single wideband with an impedance bandwidth of 45.61%. The antenna has two resonant peaks f1 and f2 which occurs at 12.1 GHz and 14.38 GHz with minimum return loss of −32.46 dB and −46.12 dB respectively. The lower resonant frequency f1 is closer to the fundamental resonance of the rectangular patch. The second resonant frequency f2 is due to current along the edges of U-slots and stubs of aperture coupled U-slot and stub rectangular microstrip antenna (AUSRMSA). This technique also enhances the gain to 9.96 dB which is 1.89 times more than the gain of conventional rectangular microstrip antenna (CRMA). The enhancement of impedance bandwidth and gain does not affect the nature of broadside radiation characteristics. The design concepts of antennas are presented and experimental results are discussed. Keywords: Microstrip, wide band, Aperture coupled, Slots.
Extended electrical tuning of quantum cascade lasers with digitalSepehrAzureSky
In this report, the sampled grating distributed feedback laser architecture is modified with digital
concatenated gratings to partially compensate for the wavelength dependence of optical gain in a
standard high efficiency quantum cascade laser core. This allows equalization of laser threshold
over a wide wavelength range and demonstration of wide electrical tuning. With only two
control currents, a full tuning range of 500 nm (236 cm1
) has been demonstrated. Emission is
single mode, with a side mode suppression of >20 dB. V C 2013 AIP Publishing LLC.
[http://dx.doi.org/10.1063/1.4841635]
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
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Performance of cognitive radio networks with maximal ratio combining over cor...Polytechnique Montreal
In this paper, we apply the maximal ratio combining (MRC) technique to achieve higher detection probability in cognitive radio networks over correlated Rayleigh fading channels. We present a simple approach to derive the probability of detection in closed-form expression. The numerical results reveal that the detection performance is a monotonically increasing function with respect to the number of antennas. Moreover, we provide sets of complementary receiver operating characteristic (ROC) curves to illustrate the effect of antenna correlation on the sensing performance of cognitive radio networks employing MRC schemes in some respective scenarios.
3D FSS with multiple transmission zeros and pseudo elliptic responsejournalBEEI
The three-dimensional frequency selective surface (3D FSS) with band reject multiple transmission zeros and pseudo-elliptic response is designed from two-dimensional (2D) periodic array of shielded micro strip lines to realize wide out-of–band radio wave rejection. The 3D FSS array consists of multimode cavities whose coupling with air can be controlled to obtain a desired frequency range. The proposed FSS with shorting via to ground exhibits pseudo-elliptic band-reject response in the frequency range from 6GHz to 14GHz. As the plane wave of linear polarization incidents perpendicularly to the shielded micro strip line with perfect electric conductor (PEC) and perfect magnetic conductor (PMC) boundary walls, two quasi-TEM modes are obtained known as air mode and substrate mode. The first 3D FSS design is a combination of two or more resonators. Furthermore, second 3D FSS design with three shorting vias result more elliptic band reject frequency response and a pass band transmission pole. All in phase resonators of design give transmission poles and out of phase combination of resonators give transmission zeros respectively. The proposed 3D FSS is designed and simulated using Ansys HFSS software. These designs exhibit an improved performance for many practical applications such as antenna sub-reflector, and spatial filters.
Design and simulation of broadband rectangular microstrip antennaBASIM AL-SHAMMARI
Abstract
In this work, many techniques are suggested and analyses for
rectangular microstrip antenna (RMSA) operating in X-band for 10 GHz
center frequency. These approaches are: lowering quality factor, shifting
feeding point , using reactive loading and modification of the patch shape.
The design of a RMSA is made to several dielectric materials, and the
selection is based upon which material gives a better antenna performance
with reduced surface wave loss. Duroid 5880 and Quartz are the best materials
for proposed design to achieve a broader Bandwidth (BW) and better
mechanical characteristics than using air. The overall antenna BW for RMSA
is increased by 11.6 % with Duroid 5880 with shifted feeding point and with
central shorting pin (Reactive loading) while that for Quartz is 17.4 %.
Modification of patch shape with similar improving techniques gives an
overall increasing VSWR bandwidth of 26.2 % for Duroid 5880 and a
bandwidth of 30.9 % for Quartz. These results are simulated using Microwave
Office package version 3.22, 2000.
Average Channel Capacity of Amplify-and-forward MIMO/FSO Systems Over Atmosph...IJECEIAES
In amplify-and-forward (AF) relay channel, when the direct link between source and destination terminals is deeply faded, the signal from the source terminal to the destination terminal propagates through the relay terminals, each of which relays a signal received from the previous terminal to the next terminal in series. This paper, we theoretically analyze the performance of multiple-input multiple-output (MIMO) AF free-space optical (FSO) systems. The AF-MIMO/FSO average channel capacity (ACC), which is expressed in terms of average spectral efficiency (ASE) is derived taking into account the atmospheric turbulence effects on the MIMO/FSO channel. They are modeled by log-normal and the gamma-gamma distributions for the cases of weak-to-strong turbulence conditions. We extract closed form mathematical expression for the evaluation of the ACC and we quantitatively discuss the influence of turbulence strength, link distance, different number of relay stations and different MIMO configurations on it.
21 15036 design of planar dielectric resonator antenna array at 28 g hz(edit)nooriasukmaningtyas
This article presents a planar array of rectangular Dielectric Resonator Antenna operating for 28 GHz applications. The proposed antenna is formed through two stages of designs which are a single element and planar array. It is made up from a ceramic material with a dielectric constant of 10 and mounted on RT/Duroid 5880 with a relative permittivity of 2.2 and a thickness of 0.254 mm. A prospective study using three different configurations of three by three planar array is done in order to obtain the best performance in terms of bandwidth, gain, and cost reduction. Besides that, this study is also conducted for a beam steering capability of each configuration. Finally, the best configuration is proposed for 5G application.
A Novel Wideband Bandpass Filter using H-shaped DGSIJECEIAES
This paper presents a novel compact wide-band bandpass filter (BPF) having good selectivity. It is designed using a dual-plane structure which consists of a parallelcoupled microstrip line on the upper surface and three H-shape defected ground structure (DGS) on the ground plane. By adding three H-shape DGS units on the ground plane, then properly adjusting their dimensions and position, the bandwidth and selectivity of the designed filter can be significantly improved. A compact prototype of wide-band microstrip bandpass filter has been designed, fabricated and measured to apply for the wireless systems. The filter shows a center frequency at 4.8 GHz, passband from 2.8 GHz to 6.8 GHz with maximum insertion loss and return loss of 0.8 dB and 40 dB, respectively. The measured results agrees well with the theoretical expectations validating the proposed design.
Narrowband Spectrum Sensing for Different Fading Channels for Cognitive Radio...IJMERJOURNAL
Abstract: Nowadays the demand of applications of wireless communication has increased rapidly which causes the scarcity of radio spectrum. To empower future wireless communication services, the radio spectrum management is a very important factor. Cognitiveradio is a promising technology which provides an innovative way to improve utilization efficiency of available electromagnetic spectrum by sensing spectrum and shares it without harmful interference to other users. Narrowband spectrum sensing is the technique where the bandwidth of active primary transmitter in the vicinity of cognitive radio is less than the coherence bandwidth of channel. Fading is one of the greatest impairment of narrowband spectrum sensing. It is deflection of the attenuation. It influences a signal over certain propagation media.A communication channel that experiences fading isknown as fading channel. The effects of fading can be reduced by several fading models. In this paper, performanceanalysis of several realistic fading models on narrowband channel using energy detection method is employed. Finally, performance comparison of various fading models is guaranteed through simulation.
Design and development of aperture coupled rectangular microstrip antenna for...eSAT Journals
Abstract This paper presents the experimental investigations carried out for obtaining wide band operation of rectangular microstrip antenna by using aperture coupled feeding technique. By incorporating U-slots with stubs on the radiating element, antenna resonates for single wideband with an impedance bandwidth of 45.61%. The antenna has two resonant peaks f1 and f2 which occurs at 12.1 GHz and 14.38 GHz with minimum return loss of −32.46 dB and −46.12 dB respectively. The lower resonant frequency f1 is closer to the fundamental resonance of the rectangular patch. The second resonant frequency f2 is due to current along the edges of U-slots and stubs of aperture coupled U-slot and stub rectangular microstrip antenna (AUSRMSA). This technique also enhances the gain to 9.96 dB which is 1.89 times more than the gain of conventional rectangular microstrip antenna (CRMA). The enhancement of impedance bandwidth and gain does not affect the nature of broadside radiation characteristics. The design concepts of antennas are presented and experimental results are discussed. Keywords: Microstrip, wide band, Aperture coupled, Slots.
Extended electrical tuning of quantum cascade lasers with digitalSepehrAzureSky
In this report, the sampled grating distributed feedback laser architecture is modified with digital
concatenated gratings to partially compensate for the wavelength dependence of optical gain in a
standard high efficiency quantum cascade laser core. This allows equalization of laser threshold
over a wide wavelength range and demonstration of wide electrical tuning. With only two
control currents, a full tuning range of 500 nm (236 cm1
) has been demonstrated. Emission is
single mode, with a side mode suppression of >20 dB. V C 2013 AIP Publishing LLC.
[http://dx.doi.org/10.1063/1.4841635]
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
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Performance of cognitive radio networks with maximal ratio combining over cor...Polytechnique Montreal
In this paper, we apply the maximal ratio combining (MRC) technique to achieve higher detection probability in cognitive radio networks over correlated Rayleigh fading channels. We present a simple approach to derive the probability of detection in closed-form expression. The numerical results reveal that the detection performance is a monotonically increasing function with respect to the number of antennas. Moreover, we provide sets of complementary receiver operating characteristic (ROC) curves to illustrate the effect of antenna correlation on the sensing performance of cognitive radio networks employing MRC schemes in some respective scenarios.
3D FSS with multiple transmission zeros and pseudo elliptic responsejournalBEEI
The three-dimensional frequency selective surface (3D FSS) with band reject multiple transmission zeros and pseudo-elliptic response is designed from two-dimensional (2D) periodic array of shielded micro strip lines to realize wide out-of–band radio wave rejection. The 3D FSS array consists of multimode cavities whose coupling with air can be controlled to obtain a desired frequency range. The proposed FSS with shorting via to ground exhibits pseudo-elliptic band-reject response in the frequency range from 6GHz to 14GHz. As the plane wave of linear polarization incidents perpendicularly to the shielded micro strip line with perfect electric conductor (PEC) and perfect magnetic conductor (PMC) boundary walls, two quasi-TEM modes are obtained known as air mode and substrate mode. The first 3D FSS design is a combination of two or more resonators. Furthermore, second 3D FSS design with three shorting vias result more elliptic band reject frequency response and a pass band transmission pole. All in phase resonators of design give transmission poles and out of phase combination of resonators give transmission zeros respectively. The proposed 3D FSS is designed and simulated using Ansys HFSS software. These designs exhibit an improved performance for many practical applications such as antenna sub-reflector, and spatial filters.
Design and simulation of broadband rectangular microstrip antennaBASIM AL-SHAMMARI
Abstract
In this work, many techniques are suggested and analyses for
rectangular microstrip antenna (RMSA) operating in X-band for 10 GHz
center frequency. These approaches are: lowering quality factor, shifting
feeding point , using reactive loading and modification of the patch shape.
The design of a RMSA is made to several dielectric materials, and the
selection is based upon which material gives a better antenna performance
with reduced surface wave loss. Duroid 5880 and Quartz are the best materials
for proposed design to achieve a broader Bandwidth (BW) and better
mechanical characteristics than using air. The overall antenna BW for RMSA
is increased by 11.6 % with Duroid 5880 with shifted feeding point and with
central shorting pin (Reactive loading) while that for Quartz is 17.4 %.
Modification of patch shape with similar improving techniques gives an
overall increasing VSWR bandwidth of 26.2 % for Duroid 5880 and a
bandwidth of 30.9 % for Quartz. These results are simulated using Microwave
Office package version 3.22, 2000.
Average Channel Capacity of Amplify-and-forward MIMO/FSO Systems Over Atmosph...IJECEIAES
In amplify-and-forward (AF) relay channel, when the direct link between source and destination terminals is deeply faded, the signal from the source terminal to the destination terminal propagates through the relay terminals, each of which relays a signal received from the previous terminal to the next terminal in series. This paper, we theoretically analyze the performance of multiple-input multiple-output (MIMO) AF free-space optical (FSO) systems. The AF-MIMO/FSO average channel capacity (ACC), which is expressed in terms of average spectral efficiency (ASE) is derived taking into account the atmospheric turbulence effects on the MIMO/FSO channel. They are modeled by log-normal and the gamma-gamma distributions for the cases of weak-to-strong turbulence conditions. We extract closed form mathematical expression for the evaluation of the ACC and we quantitatively discuss the influence of turbulence strength, link distance, different number of relay stations and different MIMO configurations on it.
21 15036 design of planar dielectric resonator antenna array at 28 g hz(edit)nooriasukmaningtyas
This article presents a planar array of rectangular Dielectric Resonator Antenna operating for 28 GHz applications. The proposed antenna is formed through two stages of designs which are a single element and planar array. It is made up from a ceramic material with a dielectric constant of 10 and mounted on RT/Duroid 5880 with a relative permittivity of 2.2 and a thickness of 0.254 mm. A prospective study using three different configurations of three by three planar array is done in order to obtain the best performance in terms of bandwidth, gain, and cost reduction. Besides that, this study is also conducted for a beam steering capability of each configuration. Finally, the best configuration is proposed for 5G application.
A Novel Wideband Bandpass Filter using H-shaped DGSIJECEIAES
This paper presents a novel compact wide-band bandpass filter (BPF) having good selectivity. It is designed using a dual-plane structure which consists of a parallelcoupled microstrip line on the upper surface and three H-shape defected ground structure (DGS) on the ground plane. By adding three H-shape DGS units on the ground plane, then properly adjusting their dimensions and position, the bandwidth and selectivity of the designed filter can be significantly improved. A compact prototype of wide-band microstrip bandpass filter has been designed, fabricated and measured to apply for the wireless systems. The filter shows a center frequency at 4.8 GHz, passband from 2.8 GHz to 6.8 GHz with maximum insertion loss and return loss of 0.8 dB and 40 dB, respectively. The measured results agrees well with the theoretical expectations validating the proposed design.
Narrowband Spectrum Sensing for Different Fading Channels for Cognitive Radio...IJMERJOURNAL
Abstract: Nowadays the demand of applications of wireless communication has increased rapidly which causes the scarcity of radio spectrum. To empower future wireless communication services, the radio spectrum management is a very important factor. Cognitiveradio is a promising technology which provides an innovative way to improve utilization efficiency of available electromagnetic spectrum by sensing spectrum and shares it without harmful interference to other users. Narrowband spectrum sensing is the technique where the bandwidth of active primary transmitter in the vicinity of cognitive radio is less than the coherence bandwidth of channel. Fading is one of the greatest impairment of narrowband spectrum sensing. It is deflection of the attenuation. It influences a signal over certain propagation media.A communication channel that experiences fading isknown as fading channel. The effects of fading can be reduced by several fading models. In this paper, performanceanalysis of several realistic fading models on narrowband channel using energy detection method is employed. Finally, performance comparison of various fading models is guaranteed through simulation.
Application of genetic algorithm to the optimization of resonant frequency of...IOSR Journals
Abstract : Microstrip antenna is gathering a lot of interest in communication systems. Genetic algorithm is a popular optimization technique and has been introduced for design optimization of microstrip patch antenna. In this paper, genetic algorithm has been used for optimization of resonant frequency of coaxially fed rectangular microstrip antenna. The investigation is made at 3 different frequencies 3GHz, 5GHz and 10GHz respectively. Patch length, patch width & feed position are taken as optimization parameters. Return loss and radiation pattern for the optimized antenna are verified using IE3D software. Accuracy of the results encourages the use of genetic algorithm. Keywords - Rectangular microstrip antenna, genetic algorithm, resonant frequency, IE3D
Application of genetic algorithm to the optimization of resonant frequency of...IOSR Journals
Microstrip antenna is gathering a lot of interest in communication systems. Genetic algorithm is a
popular optimization technique and has been introduced for design optimization of microstrip patch antenna. In
this paper, genetic algorithm has been used for optimization of resonant frequency of coaxially fed rectangular
microstrip antenna. The investigation is made at 3 different frequencies 3GHz, 5GHz and 10GHz respectively.
Patch length, patch width & feed position are taken as optimization parameters. Return loss and radiation
pattern for the optimized antenna are verified using IE3D software. Accuracy of the results encourages the use
of genetic algorithm.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, 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
Luigi Giubbolini | Time/Space-Probing Interferometer for Plasma DiagnosticsLuigi Giubbolini
By Luigi Giubbolini Published article about Rapid progress in plasma applications requires new instrumentation. Luigi Giubbolini has engineering experience in industrial, government laboratory & academic environments.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
Peak-to-Average Power Ratio Reduction in NC-OFDM based Cognitive Radio.CSCJournals
This paper presents a novel technique for reducing the peak-to-average power ratio (PAPR) in non-contiguous bands spectrum of Orthogonal Frequency Division Multiplexing (OFDM) based Cognitive Radio (CR). The proposed system exposed to carry the past channel information and the spectrum sensing to utilize the radio spectrum as well as achieving an appropriate PAPR reduction and maintaining end-to-end throughput performance by using a set of approaches in the current CR environment. The simulation results for PAPR reduction has shown that higher constellation modulation schemes are better compared to lower constellation modulation schemes.
Performance Comparison of Energy Detection Based Spectrum Sensing for Cogniti...irjes
With the rapid deployment of new wireless devices and applications, the last decade has witnessed a growing
demand for wireless radio spectrum. However, the policy of fixed spectrum assignment produces a bottleneck for more
efficient spectrum utilization, such that a great portion of the licensed spectrum is severely under-utilized. So the concept of
cognitive radio was introduced to address this issue.The inefficient usage of the limited spectrum necessitates the
development of dynamic spectrum access techniques, where users who have no spectrum licenses, also known as secondary
users, are allowed to use the temporarily unused licensed spectrum. For this purpose we have to know the presence or
absence of primary users for spectrum usage. So spectrums sensing is one of the major requirements of cognitive radio.Many
spectrum sensing techniques have been developed to sense the presence or absence of a licensed user. This paper evaluates
the performance of the energy detection based spectrum sensing technique in noisy and fading environments.The
performance of the energy detection technique will be evaluated by use of Receiver Operating Characteristics (ROC) curves
over additive white Gaussian noise (AWGN) and fading channels.
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What are the main advantages of using HR recruiter services.pdfHumanResourceDimensi1
HR recruiter services offer top talents to companies according to their specific needs. They handle all recruitment tasks from job posting to onboarding and help companies concentrate on their business growth. With their expertise and years of experience, they streamline the hiring process and save time and resources for the company.
Falcon stands out as a top-tier P2P Invoice Discounting platform in India, bridging esteemed blue-chip companies and eager investors. Our goal is to transform the investment landscape in India by establishing a comprehensive destination for borrowers and investors with diverse profiles and needs, all while minimizing risk. What sets Falcon apart is the elimination of intermediaries such as commercial banks and depository institutions, allowing investors to enjoy higher yields.
Cracking the Workplace Discipline Code Main.pptxWorkforce Group
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Kseniya Leshchenko: Shared development support service model as the way to ma...Lviv Startup Club
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A Memorandum of Association (MOA) is a legal document that outlines the fundamental principles and objectives upon which a company operates. It serves as the company's charter or constitution and defines the scope of its activities. Here's a detailed note on the MOA:
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1. LOW CROSS-POLARIZED COMPACT RANGE FEEDS
Jeffrey A. Fordham
Microwave Instrumentation Technologies, LLC.
4500 River Green Parkway, Suite 200
Duluth, Georgia 30091
James H. Cook, Jr.
Scientific-Atlanta, Inc.
4311 Communications Drive 30-J
P.O. Box 6850
Norcross, GA 30091
Abstract In these types of geometry systems and assuming the
reflector(s) are properly aligned, the cross-polarization
Compact antenna test ranges intended for low cross- discrimination of the compact range feed becomes the
polarization antenna measurements require the use of dominant factor. Feeds used for single reflector compact
feeds with polarization ratios typically greater than 40 ranges typically are designed to only have -35 dB of cross-
dB across the included angle of the quiet zone as well as polarization on-axis and -25 dB across the quiet zone since
across the frequency band of interest. The design for a the cross-polarization induced by the feed tilt angle will
series of circular corrugated aperture feeds to meet dominate the quiet zone. In order to support low cross-
these requirements is presented. The feeds are based polarization compact range systems, a new design
on a circular waveguide OMT covering a full requirement has been placed upon the antenna used to feed
waveguide frequency band with interchangeable these ranges.
corrugated apertures to cover three sub-bands. In
order to validate the design of this series of scalar feeds, The requirement for this new feed is that it must possess a
high accuracy cross-polarization data was collected. linear polarization ratio greater than the desired
The primary limiting factor in the measurement of the measurement levels across the full projected aperture of
polarization ratio was the finite polarization ratio of the quiet zone as illustrated in Figure 1. A further
the source antennas. A technique for correcting for the requirement that the feed operate across the bandwidth of
polarization ratio of the source is presented along with the system further complicates the design.
measured data on the feeds. The technique begins with For the geometry shown in Figure 1, where the primary
the accurate characterization of the linear polarization feed axis is pointed at the vertex of the compact range
ratio of the standard gain horns using a three antenna reflector, this translates into a linear polarization
technique, followed by pattern measurements of the requirement within about a 40-degree cone about the feed
feeds, and ends with the removal of the polarization axis. To support high accuracy compact range
error due to the source antenna from the measured measurements utilizing the geometry shown in Figure 1,
data. Measured data on these feeds is presented before the cross-polarization introduced by the source should be
and after data correction along with data predicted on the order of -43 dB.
using the CHAMP® moment method software.
2. Feed Configuration
Keywords: Cross-Polarization, Compact Range,
Measurement Systems The feed configuration chosen to meet these design
requirements is a corrugated circular aperture similar to the
1. Introduction: prime-focus waveguide feeds shown in Olver, et al[3].
Conventional compact ranges are limited by the geometry These new feeds, however, use a corrugation design with
induced cross-polarization errors associated with an offset stepped rings, and a reduced aperture to widen the
feed to cross-polarization measurements of about -30 dB beamwidth of the feed and to equalize the E and H plane
for large test apertures. To collect high-accuracy cross- beamwidths. The aperture design of one of these feeds is
polarization measurements in a compact range, either a shown in Figure 2.
dual-reflector compact range configuration or a unique
single reflector with a post processing technique such as
the ECCA technique [1,2] must be used.
2. Figure 1: Compact Range Feed pointing angles overlaid on the Layout of the Quiet Zone of a MI Technologies
Model 5712 Compact Antenna Range Reflector.
These feeds were designed to support either single λg2 = wavelength in the aperture at the low end of the band
polarization or switchable dual linear polarization. In
designing these feeds further requirements were placed on BW p = Percentage bandwidth.
the compact range feed system to support an operational Each of these subbands are covered by a separate
band of frequencies from 1.1 GHz through 40 GHz. removable aperture section.
This operational band is covered by the MI Technologies
Model 31[4] and 33 series of compact range feeds. Each of
these feeds covers a typical waveguide band of
frequencies. In order to meet the cross-polarization
requirements across each waveguide band, the bands were
broken down into three subbands of approximately 23%
bandwidth based on the wavelength of the feed in the
waveguide according to the following equation.
λ g1 − λ g 2
BW p = * 100 %
λ g1 + λ g 2 (1) Figure 2: Cross Section of the Low-Cross
Polarization Compact Range Feed Aperture.
Where,
λg1 = wavelength in the aperture at the high end of the
band
3. Figure 3: E-plane, H-plane, and intercardinal plane primary polarization, and intercardinal plane cross-polarization for
the Model 31-12M_LB at 12.4 GHz.
3. Predicted Results A measurement program was undertaken to characterize a
number of standard gain horns to be able to select the one
This series of feeds was designed with the aid of the with the lowest cross-polarization. This program utilized
"Corrugated Horn Analysis by Moment Method Program," the three-antenna polarization characterization technique
(CHAMP) code. outlined by Newell [5].
Figure 3 shows E -plane, H-plane, and intercardinal plane Using the complex linear polarization ratio and tilt angle
primary polarization along with the cross-polarization in determined by the three-antenna method, the source
the intercardinal plane for the Model 31-12M_LB antenna cross-polarization contribution to the measurement
operating at 12.4 GHz. Note that over the 40-degree cone was removed using equation 7.
about the feed axis, the highest cross-polarization level is
-43 dB and occurs in the intercardinal plane. Equation 7 is derived from the reaction equations as
follows:
Figure 4 shows the predicted performance of the Model
31-1.7M-HB feed at the low and high operating
frequencies across the quiet zone of the feed/reflector D ' AS = X A * X S − Y A * YS (2)
system.
4. Measurement Technique D " AS = X A * X S + YA *YS (3)
In order to verify the cross-polarization levels predicted
using the CHAMP moment method software, a set of feeds Where;
was constructed and tested. This test program was
constrained by the difficulties of making cross-polarization D'AS = Co-polarized measurement
measurements on the order of -40 to -50 dB. After most
D" AS = Cross-Polarized Measurement
sources of errors in the measurement were accounted for,
the error associated with the linear polarization ratio of the X, Y = complex components of the elliptically polarized
source antenna was the most significant. wave. A, S represent the AUT and Source respectively.
Taking the ratio of equations 2 and 3 and substituting;
XA XS
pA = (4) pS = (5)
YA YS
4. Yields the ratio of the co-polarized to the cross-polarized
measurement QAS ,
pA + pS
QAS = (6)
p A * pS − 1
Finally, solving for p A gives the corrected AUT linear
polarization ratio.
p S + QAS
pA = (7)
QAS − 1
5. Measured Data
(a)
The cross-polarization required by these feeds is -43 dB
over a 40-degree cone about the centerline of the feed.
The maximum cross-polarization from a scalar feed occurs
in the intercardinal planes (±45 degrees). The intercardinal
plane patterns for the Model 31-12M-LB is shown in
Figures 5a and 5b for the low and high ends of its
operational band. For each plot presented, 5 traces are
shown; the measured and predicted co-polarized patterns,
and measured, predicted and corrected cross-polarized
patterns. The corrected cross-polarized patterns are
corrected for the error introduced by the standard gain
horn's linear polarization ratio using the method outlined in
Section 4.
The first plot in Figure 5 is taken on the lowband aperture
at 12.4 GHz. The corrected cross-polarization meets the
required specification over a ±45° range and agrees well
with the predicted data. The standard gain horn used for
this measurement had a linear polarization ratio of -48 dB.
The second plot, Figure 5(b), was taken using a standard
gain horn with a measured linear polarization ratio of
greater than -72 dB. Therefore this source horn did not (b)
introduce much error into the cross-polarization
measurement. This plot shows excellent agreement Figure 4: Cross-Polarization across the quiet zone shown
between the measured and predicted cross-polarization. in Figure 1 for the Model 31-1.1M-HB. (a) 1.5 GHz (b) 1.7
GHz
The final design requirement to test is the return loss for
the feed. Figure 5(c) shows the return loss for the Model
12M-LB for 12.4 GHz to 18.0 GHz although the actual 6. Summary
operating band for this feed is only 12.4 to 14.0 GHz. The
worst case return is -13.5 dB across the operating band. A series of circular corrugated aperture feeds to meet the
requirements for testing low cross-polarized antennas in
compact ranges has been presented. This series of very
5. low, wide bandwidth feeds have been developed to cover a
frequency band from 1.1 to 40.0 GHz based on the MI
Technologies' Model 31 waveguide OMT and Model 33
feeds. Individually each feed aperture covers a bandwidth
of approximately 23% with 3 apertures per full waveguide
band. These feeds have been developed, tested and shown
to exhibit a cross-polarization greater than 43 dB across a
full 40° cone about the centerline of the aperture.
References
[1]"Cross-Polarization Measurement Accuracy
Improvement on a Single Reflector Compact Range,"
David C. Cook, James H. Cook, Jr., Rebecca Kaffezakis,
(a)
AMTA 1996 Proceedings, p. 394
[2] "High-Accuracy Cross-Polarization Measurements
Using a Single-Reflector Compact Range," Christopher A.
Rose and James H. Cook, Jr., IEEE Antennas and
Propagation Magazine, Vol. 41, No. 2, April 1999.
[3] Microwave Horns and Feeds, A.D. Olver, P.J.B.
Clarricoats, A.A. Kishk, and L. Shafai, New York: IEEE
Press, 1994.
[4] "A Dual-Ported, Dual-Polarized Spherical Near-Field
Probe," J.R. Jones and D.P. Hardin, AMTA 1983
Proceedings
[5] "Improved Polarization Measurements Using a
Modified Three Antenna Technique," Allen C. Newell, (b)
Procedings of IEEE Int. AP Symp., Urbina-Champagne,
Ill., June, 1975.
(c)
Figure 5: Performance Data for the Model 31M-12-LB
feed. (a) Pattern data at 12.4 GHz. (b) Pattern data at 14.0
GHz. (c) Return Loss data vs. the full waveguide
bandwidth of the Model 31 Feed.