The document describes the design and testing of a circular microstrip patch array antenna for C-band altimeter systems. It discusses using an array of four circular microstrip elements with equal size and spacing to achieve a gain of 12 dB. The antenna was simulated using HFSS and Microwave Office software. Comparison of simulated and measured results showed good agreement, achieving the design goals.
Implementation of Digital Beamforming Technique for Linear Antenna Arraysijsrd.com
A digital Beamforming technique used for increased channel capacity and also increased signal to noise and interference ratio. In smart antenna, different type of radiation pattern of an antenna can be changed either by selecting appropriate weights or by changing the array geometry. This paper presented based on auxiliary phase algorithm by using this algorithm in linear antenna array determine the array pattern approximating the auxiliary function in both amplitude and phase. Cost function involving auxiliary function and array pattern is minimized by modifying the pattern.
This document describes the design and analysis of a hexagonal fractal antenna for ultra-wideband applications from 3-10.6 GHz. The antenna was designed on an FR4 substrate with a dielectric constant of 4.4 and thickness of 1.6mm. It was fed by a 50-ohm microstrip line. The antenna was simulated using HFSS software. Simulation results showed return loss below -10dB, VSWR below 2, and omnidirectional radiation patterns over the frequency band. Removing triangular patterns from the hexagonal patch increased the effective current path length and bandwidth of the antenna. The hexagonal fractal antenna design achieved good performance for UWB applications.
Comparative study of slot loaded rectangular and triangular microstrip array ...eSAT Publishing House
This document presents a comparative study of two slot loaded microstrip array antenna designs - a rectangular design (TS-RMAA) and triangular design (TS-ETMAA). The experimental results show that the TS-ETMAA design has a 7.35% impedance bandwidth, which is 1.12 times greater than the 6.54% bandwidth of the TS-RMAA design. Theoretical calculations matching the experimental results also show the triangular design having a greater bandwidth of 7.12% compared to 5.55% for the rectangular design. In conclusion, the triangular microstrip antenna provides both enhanced impedance bandwidth and compactness compared to the rectangular design.
The document describes the design of a microstrip patch antenna with circular and step-shaped slots for S-band applications. A rectangular patch antenna with coaxial feed and step slots on four sides and a circular slot in the center is proposed. The antenna is simulated in HFSS and achieves a return loss of -38.42 dB at 3.73 GHz. The antenna has a 2D gain of 7.59 dB, elliptical polarization, and radiation patterns that make it suitable for weather radar applications in the S-band frequency range.
The document summarizes research on thinning semi-elliptical and quarter-elliptical antenna arrays using genetic algorithm optimization to reduce side-lobe levels. Key points:
1) Genetic algorithms were used to optimize thinning of semi-elliptical and quarter-elliptical arrays with uniform excitation and spacing to produce narrow beams without degrading performance.
2) Simulation results showed thinning using genetic algorithms reduced side-lobe levels of the arrays compared to fully populated arrays.
3) Maximum side-lobe levels, beamwidths, and other metrics were tabulated for various array sizes and geometries, indicating thinning effectively lowered side-lobes.
Mathematical Modeling of Cylindrical Dielectric Resonator Antenna for Applica...IJERA Editor
We are moving forward in an era where adaptive antenna arrays will be capable of identifying the direction of the incoming signal and steering the transmitted beam in appropriate directions. It has already been proposed that Dielectric Resonator Antennas (DRAs) can be good candidates for such applications. In this paper, we have carefully analyzed the theoretical model of a DRA and have proposed various mathematical methods for its analysis. The methods proposed herein can reduce the complexity of analysis and design of circuits involving DRAs.
This document describes the design and simulation of a multiband patch antenna using a Pythagorean fractal structure. In the base antenna design, resonance is achieved at 8GHz. The first fractal iteration uses a Pythagorean triangle equation to modify the patch shape. In simulation, this first iteration achieves two resonances, at 8.2GHz and 9.2GHz, when fed by both a coaxial probe and microstrip line. While the radiation patterns are not perfectly broadside, radiation still occurs in the upper quadrant. The simple fractal structure provides a potential way to miniaturize antennas while achieving multiband performance.
Variable radiation pattern from co axial probe fed rectangular patch antenna ...eSAT Journals
Abstract The idea of obtaining variable radiation patterns from the same antenna is important aspect in achieving the adaptive antenna systems. In the EM signal processing the change of radiation signifies the information to be transmitted, its rate of transmission, the geographical changes and direction to transmit etc. i.e. each time when the requirement arises to change the radiation pattern it has to be done to satisfy the conditions. Electronically steerable antennas were used where the antenna radiation will be altered by varying the feed and similar case is applied for shaped patterns from array antenna where the feed to be given will be calculated and given accordingly. In the present concept the metamaterials are used to obtain different radiation patterns occurred at different operating frequencies using the same antenna without changing the antenna physically are varying its feed. Key Words: Inductance, capacitance, operating frequency, variable radiation, enhancement, radiation cancellation.
Implementation of Digital Beamforming Technique for Linear Antenna Arraysijsrd.com
A digital Beamforming technique used for increased channel capacity and also increased signal to noise and interference ratio. In smart antenna, different type of radiation pattern of an antenna can be changed either by selecting appropriate weights or by changing the array geometry. This paper presented based on auxiliary phase algorithm by using this algorithm in linear antenna array determine the array pattern approximating the auxiliary function in both amplitude and phase. Cost function involving auxiliary function and array pattern is minimized by modifying the pattern.
This document describes the design and analysis of a hexagonal fractal antenna for ultra-wideband applications from 3-10.6 GHz. The antenna was designed on an FR4 substrate with a dielectric constant of 4.4 and thickness of 1.6mm. It was fed by a 50-ohm microstrip line. The antenna was simulated using HFSS software. Simulation results showed return loss below -10dB, VSWR below 2, and omnidirectional radiation patterns over the frequency band. Removing triangular patterns from the hexagonal patch increased the effective current path length and bandwidth of the antenna. The hexagonal fractal antenna design achieved good performance for UWB applications.
Comparative study of slot loaded rectangular and triangular microstrip array ...eSAT Publishing House
This document presents a comparative study of two slot loaded microstrip array antenna designs - a rectangular design (TS-RMAA) and triangular design (TS-ETMAA). The experimental results show that the TS-ETMAA design has a 7.35% impedance bandwidth, which is 1.12 times greater than the 6.54% bandwidth of the TS-RMAA design. Theoretical calculations matching the experimental results also show the triangular design having a greater bandwidth of 7.12% compared to 5.55% for the rectangular design. In conclusion, the triangular microstrip antenna provides both enhanced impedance bandwidth and compactness compared to the rectangular design.
The document describes the design of a microstrip patch antenna with circular and step-shaped slots for S-band applications. A rectangular patch antenna with coaxial feed and step slots on four sides and a circular slot in the center is proposed. The antenna is simulated in HFSS and achieves a return loss of -38.42 dB at 3.73 GHz. The antenna has a 2D gain of 7.59 dB, elliptical polarization, and radiation patterns that make it suitable for weather radar applications in the S-band frequency range.
The document summarizes research on thinning semi-elliptical and quarter-elliptical antenna arrays using genetic algorithm optimization to reduce side-lobe levels. Key points:
1) Genetic algorithms were used to optimize thinning of semi-elliptical and quarter-elliptical arrays with uniform excitation and spacing to produce narrow beams without degrading performance.
2) Simulation results showed thinning using genetic algorithms reduced side-lobe levels of the arrays compared to fully populated arrays.
3) Maximum side-lobe levels, beamwidths, and other metrics were tabulated for various array sizes and geometries, indicating thinning effectively lowered side-lobes.
Mathematical Modeling of Cylindrical Dielectric Resonator Antenna for Applica...IJERA Editor
We are moving forward in an era where adaptive antenna arrays will be capable of identifying the direction of the incoming signal and steering the transmitted beam in appropriate directions. It has already been proposed that Dielectric Resonator Antennas (DRAs) can be good candidates for such applications. In this paper, we have carefully analyzed the theoretical model of a DRA and have proposed various mathematical methods for its analysis. The methods proposed herein can reduce the complexity of analysis and design of circuits involving DRAs.
This document describes the design and simulation of a multiband patch antenna using a Pythagorean fractal structure. In the base antenna design, resonance is achieved at 8GHz. The first fractal iteration uses a Pythagorean triangle equation to modify the patch shape. In simulation, this first iteration achieves two resonances, at 8.2GHz and 9.2GHz, when fed by both a coaxial probe and microstrip line. While the radiation patterns are not perfectly broadside, radiation still occurs in the upper quadrant. The simple fractal structure provides a potential way to miniaturize antennas while achieving multiband performance.
Variable radiation pattern from co axial probe fed rectangular patch antenna ...eSAT Journals
Abstract The idea of obtaining variable radiation patterns from the same antenna is important aspect in achieving the adaptive antenna systems. In the EM signal processing the change of radiation signifies the information to be transmitted, its rate of transmission, the geographical changes and direction to transmit etc. i.e. each time when the requirement arises to change the radiation pattern it has to be done to satisfy the conditions. Electronically steerable antennas were used where the antenna radiation will be altered by varying the feed and similar case is applied for shaped patterns from array antenna where the feed to be given will be calculated and given accordingly. In the present concept the metamaterials are used to obtain different radiation patterns occurred at different operating frequencies using the same antenna without changing the antenna physically are varying its feed. Key Words: Inductance, capacitance, operating frequency, variable radiation, enhancement, radiation cancellation.
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.
The document reviews fractal geometries for wireless applications. It discusses fractal antennas using Sierpinski gasket, Sierpinski carpet, Koch curve, and Hilbert curve shapes. These fractal antennas have multiband behavior, compact size and support multiple frequencies. The document provides examples of fractal antennas for applications such as UWB devices, aeronautical navigation and wireless power transmission systems. It concludes fractal antennas are well suited for wireless communication due to their ability to operate at multiple frequencies while maintaining a small size.
ARRAY FACTOR OPTIMIZATION OF AN ACTIVE PLANAR PHASED ARRAY USING EVOLUTIONARY...jantjournal
Evolutionary algorithms (EAs) have the potential to handle complex, multi-dimensional optimization problems in the field of phased array. Out of different EAs, particle swarm optimization (PSO) is a popular choice. In a phased array, antenna element failure is a common phenomenon and this leads to degradation
of the array factor (AF) pattern, primarily in terms of increased side lobe levels (SLLs), displacement of nulls and reduction in the null depths. The recovery of a degraded pattern using a cost and time-effective approach is on demand. In this context, an attempt made to obtain an optimized AF pattern after fault in a
49 elements quasi-circular aperture equilateral triangular grid active planar phased array using PSO. In the paper, multiple cases on recovery are discussed having a maximum 20% element failure. Each recovery is also further evaluated by different statistical analyses. A dedicated software tool was developed to carry out the work presented in this paper.
A novel methodology for time-domain characterization of a full anechoic chamb...IJECEIAES
In this paper we present a novel methodology for time-domain characterization of a full anechoic chamber using the finite integral method. This approach is considered fast, accurate and not intensive for computer resources. The validation of this approach is carried out on CST-microwave studio for a full anechoic chamber intended for antennas measurement applications and electromagnetic exposure evaluation for cellular network. Low, medium and high gain sources are used in this study. The simulations are realized on a personal computer of medium performances (i7 CPU and 16 GB of RAM). The stability and the convergence of our approach are obtained thanks to local mesh and auto-regressive linear filtering techniques. The minimization of the simulation time is based on use of the Huygens sources in the place of the antennas. The maximum error of the chamber as well as the wave depolarization into the chamber are at one with the previous work and the catalogs of the principles chambers manufacturers for the proposed tests in this paper. The Full simulations time is about 15 hours in average.
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
This document describes the design and simulation of stacked printed log-periodic antenna arrays for C-band applications. Log-periodic antennas have wide bandwidth and constant impedance over frequency. The paper studies arrays with 5, 7, and 9 radiating elements to increase bandwidth. Simulation results using the method of moments show that bandwidth increases from 17.96% for a 5-element array to 31.53% for a 9-element array. Gain also increases proportionally with the number of elements. The multilayer structure and coupling slot feeding technique contribute to enhanced bandwidth performance.
Particle Swarm Optimization for the Path Loss Reduction in Suburban and Rural...IJECEIAES
In the present work, a precise optimization method is proposed for tuning the parameters of the COST231 model to improve its accuracy in the path loss propagation prediction. The Particle Swarm Optimization is used to tune the model parameters. The predictions of the tuned model are compared with the most popular models. The performance criteria selected for the comparison of various empirical path loss models is the Root Mean Square Error (RMSE). The RMSE between the actual and predicted data are calculated for various path loss models. It turned out that the tuned COST 231 model outperforms the other studied models.
Three complementary split spiral resonators (CSSRs) are used to reduce mutual coupling between two nearby microstrip patch antennas operating at 6.58 GHz. Simulation and measurement results show that using three vertically arranged CSSRs etched on the ground plane reduces the mutual coupling between the antennas by 23 dB. Characterization of the CSSR unit cell shows it behaves as a single negative metamaterial. The CSSRs block surface waves on the substrate to minimize coupling between the antenna elements while maintaining a low-profile compact structure with minimal impact on antenna performance.
Enhancing the Radiation Pattern of Phase Array Antenna Using Particle Swarm O...IOSR Journals
The document describes a study that uses particle swarm optimization to enhance the radiation pattern of a phase array antenna by minimizing sidelobe levels. It first provides background on issues with high sidelobes in phase array antennas, such as power losses and interference. It then summarizes previous research using techniques like genetic algorithms for antenna array optimization. The study models the radiation pattern of linear arrays with different element numbers and calculates gain, finding that gain increases with more elements. However, sidelobe levels also increase relatively. Therefore, the study proposes using particle swarm optimization to optimize current excitation and control sidelobe levels while maintaining a narrow beamwidth.
Ill-posedness formulation of the emission source localization in the radio- d...Ahmed Ammar Rebai PhD
To contact the authors : tarek.salhi@gmail.com and ahmed.rebai2@gmail.com
In the field of radio detection in astroparticle physics, many studies have shown the strong dependence of the solution of the radio-transient sources localization problem (the radio-shower time of arrival on antennas) such solutions are purely numerical artifacts. Based on a detailed analysis of some already published results of radio-detection experiments like : CODALEMA 3 in France, AERA in Argentina and TREND in China, we demonstrate the ill-posed character of this problem in the sens of Hadamard. Two approaches have been used as the existence of solutions degeneration and the bad conditioning of the mathematical formulation problem. A comparison between experimental results and simulations have been made, to highlight the mathematical studies. Many properties of the non-linear least square function are discussed such as the configuration of the set of solutions and the bias.
This document summarizes the design process of a 10:1 frequency-independent logarithmically periodic dipole antenna operating from 500 MHz to 5 GHz. It describes the theoretical background of log-periodic antennas and outlines the design steps taken. These include calculating tooth radii and angles to achieve the desired performance. Simulations were conducted and a quarter-wave transformer was added to match the impedance. Both simulated and measured results are presented, although the bandwidth goals were not fully achieved. Potential sources of error are discussed.
This document summarizes a research paper about designing beampatterns for MIMO radar systems using a covariance-based method while accounting for the locations of transmitter antennas. It discusses how changing antenna locations is equivalent to changing carrier frequency. The paper proposes optimizing two cost functions: 1) Pushing sidelobes away from the main lobe to minimize interference, and 2) Maximizing power around target locations without extra sidelobes to improve target detection. It formulates these cost functions and outlines an algorithm to optimize them using the cross-correlation matrix and antenna locations as design variables.
International Journal of Computational Engineering Research(IJCER) ijceronline
nternational Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
For high performance communication systems, Side Lobe Level (SLL) reduction and improved directivity are the goal of antenna designers. In the recent years, many optimization techniques of antenna design are occupying demanding place over the analytical techniques. Though they have contributed attractive solutions, it is often obvious to select one that meets the particular design need at hand. In this paper, an optimization technique called Self-adaptive Differential Evolution (SaDE) that can be able to learn and behave intelligently along with hyper beam forming is integrated to determine an optimal set of excitation weights in the design of EcAA. Non-uniform excitation weights of the individual array elements of EcAA are performed to obtain reduced SLL, high directivity and flexible radiation pattern. To evaluate the improved performance of the proposed SaDE optimized hyper beam, comparison are done with uniformly excited, SaDE without hyper beam and Genetic Algorithm (GA). In general, the proposed work of pattern synthesis has resulted in much better reduction of SLL and FNBW than both the uniformly excited and thinned EcAA. The results of this study clearly reveal that the SLL highly reduced at a very directive beamwidth.
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.
Circularly polarized microstrip antenna with reactive load design for wireles...BASIM AL-SHAMMARI
This paper presents a design of microstrip antenna for IEEE 802.11b and for IEEE 802.11g using a nearly square patch antenna, excited by a standard miniature adapter probe feed line. The patch and ground plain are separated by a substrate; the radiating patch is loaded by a central shorting pin and feeding probe loaded by a series capacitor. This antenna has wide bandwidth in the frequency band of (WLAN) and with a return loss ≤ −10 dB from 2.4 GHz to 2.48 GHz exhibits circularly polarized far field radiation pattern.
The proposed antennas have been simulated and analyzed using method of moments (MoM) based software package Microwave Office 2008 v8.0. The results show that the bandwidth of the antenna increases by using reactive load. The simulated gain of the antenna is over 6 dB.
Circularly polarized microstrip antenna with reactive load design for wireles...BASIM AL-SHAMMARI
Abstract
This paper presents a design of microstrip antenna for IEEE 802.11b and for IEEE 802.11g using a nearly square patch antenna, excited by a standard miniature adapter probe feed line. The patch and ground plain are separated by a substrate; the radiating patch is loaded by a central shorting pin and feeding probe loaded by a series capacitor. This antenna has wide bandwidth in the frequency band of (WLAN) and with a return loss ≤ −10 dB from 2.4 GHz to 2.48 GHz exhibits circularly polarized far field radiation pattern.
The proposed antennas have been simulated and analyzed using method of moments (MoM) based software package Microwave Office 2008 v8.0. The results show that the bandwidth of the antenna increases by using reactive load. The simulated gain of the antenna is over 6 dB.
This document describes the design of a patch antenna that can operate at multiple frequency bands using metamaterials. A rectangular patch antenna is designed to operate at 3 GHz. Then, a unit cell of complementary split-ring resonator (CSRR) is designed to also operate at 3 GHz. An array of this CSRR unit cell is placed on the patch to act as a metamaterial and enable multiband operation. Specifically, the antenna is designed to resonate in the Bluetooth, WiMax and Wi-Fi bands. Simulation results using HFSS software show that the proposed antenna provides good performance in terms of voltage standing wave ratio, return loss and impedance matching for multiband operation.
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).
This document discusses the performance analysis of a microstrip printed antenna conformed on a cylindrical body operating at a resonance frequency of 4.6 GHz for the TM01 mode. It begins with an introduction to microstrip antennas and the effects of curvature. It then presents mathematical models for the electric and magnetic fields, input impedance, return loss, and voltage standing wave ratio for a curved microstrip antenna. Results show the resonance frequency shifts 35 MHz as the radius of curvature changes from 6 mm to a flat antenna. Graphs also show the real and imaginary parts of input impedance vary with frequency for different radii of curvature.
13. Analysis of Half TEm horn type antenna for High power Impulse radiation a...Dr. SACHIN UMBARKAR
This document discusses the analysis and design of a half transverse electromagnetic (HTEM) horn-type antenna for high-power impulse radiation applications. It presents mathematical formulations for calculating key antenna parameters like characteristic impedance that consider the isolation distance between the antenna arm and reflector. Simulation and experimental results are used to determine the optimal geometric design parameters, such as tapering angle and flair angle, that maximize antenna gain. Formulas show how parameters like electric and magnetic fields depend on the antenna geometry, pulse characteristics, and material properties.
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.
The document reviews fractal geometries for wireless applications. It discusses fractal antennas using Sierpinski gasket, Sierpinski carpet, Koch curve, and Hilbert curve shapes. These fractal antennas have multiband behavior, compact size and support multiple frequencies. The document provides examples of fractal antennas for applications such as UWB devices, aeronautical navigation and wireless power transmission systems. It concludes fractal antennas are well suited for wireless communication due to their ability to operate at multiple frequencies while maintaining a small size.
ARRAY FACTOR OPTIMIZATION OF AN ACTIVE PLANAR PHASED ARRAY USING EVOLUTIONARY...jantjournal
Evolutionary algorithms (EAs) have the potential to handle complex, multi-dimensional optimization problems in the field of phased array. Out of different EAs, particle swarm optimization (PSO) is a popular choice. In a phased array, antenna element failure is a common phenomenon and this leads to degradation
of the array factor (AF) pattern, primarily in terms of increased side lobe levels (SLLs), displacement of nulls and reduction in the null depths. The recovery of a degraded pattern using a cost and time-effective approach is on demand. In this context, an attempt made to obtain an optimized AF pattern after fault in a
49 elements quasi-circular aperture equilateral triangular grid active planar phased array using PSO. In the paper, multiple cases on recovery are discussed having a maximum 20% element failure. Each recovery is also further evaluated by different statistical analyses. A dedicated software tool was developed to carry out the work presented in this paper.
A novel methodology for time-domain characterization of a full anechoic chamb...IJECEIAES
In this paper we present a novel methodology for time-domain characterization of a full anechoic chamber using the finite integral method. This approach is considered fast, accurate and not intensive for computer resources. The validation of this approach is carried out on CST-microwave studio for a full anechoic chamber intended for antennas measurement applications and electromagnetic exposure evaluation for cellular network. Low, medium and high gain sources are used in this study. The simulations are realized on a personal computer of medium performances (i7 CPU and 16 GB of RAM). The stability and the convergence of our approach are obtained thanks to local mesh and auto-regressive linear filtering techniques. The minimization of the simulation time is based on use of the Huygens sources in the place of the antennas. The maximum error of the chamber as well as the wave depolarization into the chamber are at one with the previous work and the catalogs of the principles chambers manufacturers for the proposed tests in this paper. The Full simulations time is about 15 hours in average.
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
This document describes the design and simulation of stacked printed log-periodic antenna arrays for C-band applications. Log-periodic antennas have wide bandwidth and constant impedance over frequency. The paper studies arrays with 5, 7, and 9 radiating elements to increase bandwidth. Simulation results using the method of moments show that bandwidth increases from 17.96% for a 5-element array to 31.53% for a 9-element array. Gain also increases proportionally with the number of elements. The multilayer structure and coupling slot feeding technique contribute to enhanced bandwidth performance.
Particle Swarm Optimization for the Path Loss Reduction in Suburban and Rural...IJECEIAES
In the present work, a precise optimization method is proposed for tuning the parameters of the COST231 model to improve its accuracy in the path loss propagation prediction. The Particle Swarm Optimization is used to tune the model parameters. The predictions of the tuned model are compared with the most popular models. The performance criteria selected for the comparison of various empirical path loss models is the Root Mean Square Error (RMSE). The RMSE between the actual and predicted data are calculated for various path loss models. It turned out that the tuned COST 231 model outperforms the other studied models.
Three complementary split spiral resonators (CSSRs) are used to reduce mutual coupling between two nearby microstrip patch antennas operating at 6.58 GHz. Simulation and measurement results show that using three vertically arranged CSSRs etched on the ground plane reduces the mutual coupling between the antennas by 23 dB. Characterization of the CSSR unit cell shows it behaves as a single negative metamaterial. The CSSRs block surface waves on the substrate to minimize coupling between the antenna elements while maintaining a low-profile compact structure with minimal impact on antenna performance.
Enhancing the Radiation Pattern of Phase Array Antenna Using Particle Swarm O...IOSR Journals
The document describes a study that uses particle swarm optimization to enhance the radiation pattern of a phase array antenna by minimizing sidelobe levels. It first provides background on issues with high sidelobes in phase array antennas, such as power losses and interference. It then summarizes previous research using techniques like genetic algorithms for antenna array optimization. The study models the radiation pattern of linear arrays with different element numbers and calculates gain, finding that gain increases with more elements. However, sidelobe levels also increase relatively. Therefore, the study proposes using particle swarm optimization to optimize current excitation and control sidelobe levels while maintaining a narrow beamwidth.
Ill-posedness formulation of the emission source localization in the radio- d...Ahmed Ammar Rebai PhD
To contact the authors : tarek.salhi@gmail.com and ahmed.rebai2@gmail.com
In the field of radio detection in astroparticle physics, many studies have shown the strong dependence of the solution of the radio-transient sources localization problem (the radio-shower time of arrival on antennas) such solutions are purely numerical artifacts. Based on a detailed analysis of some already published results of radio-detection experiments like : CODALEMA 3 in France, AERA in Argentina and TREND in China, we demonstrate the ill-posed character of this problem in the sens of Hadamard. Two approaches have been used as the existence of solutions degeneration and the bad conditioning of the mathematical formulation problem. A comparison between experimental results and simulations have been made, to highlight the mathematical studies. Many properties of the non-linear least square function are discussed such as the configuration of the set of solutions and the bias.
This document summarizes the design process of a 10:1 frequency-independent logarithmically periodic dipole antenna operating from 500 MHz to 5 GHz. It describes the theoretical background of log-periodic antennas and outlines the design steps taken. These include calculating tooth radii and angles to achieve the desired performance. Simulations were conducted and a quarter-wave transformer was added to match the impedance. Both simulated and measured results are presented, although the bandwidth goals were not fully achieved. Potential sources of error are discussed.
This document summarizes a research paper about designing beampatterns for MIMO radar systems using a covariance-based method while accounting for the locations of transmitter antennas. It discusses how changing antenna locations is equivalent to changing carrier frequency. The paper proposes optimizing two cost functions: 1) Pushing sidelobes away from the main lobe to minimize interference, and 2) Maximizing power around target locations without extra sidelobes to improve target detection. It formulates these cost functions and outlines an algorithm to optimize them using the cross-correlation matrix and antenna locations as design variables.
International Journal of Computational Engineering Research(IJCER) ijceronline
nternational Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
For high performance communication systems, Side Lobe Level (SLL) reduction and improved directivity are the goal of antenna designers. In the recent years, many optimization techniques of antenna design are occupying demanding place over the analytical techniques. Though they have contributed attractive solutions, it is often obvious to select one that meets the particular design need at hand. In this paper, an optimization technique called Self-adaptive Differential Evolution (SaDE) that can be able to learn and behave intelligently along with hyper beam forming is integrated to determine an optimal set of excitation weights in the design of EcAA. Non-uniform excitation weights of the individual array elements of EcAA are performed to obtain reduced SLL, high directivity and flexible radiation pattern. To evaluate the improved performance of the proposed SaDE optimized hyper beam, comparison are done with uniformly excited, SaDE without hyper beam and Genetic Algorithm (GA). In general, the proposed work of pattern synthesis has resulted in much better reduction of SLL and FNBW than both the uniformly excited and thinned EcAA. The results of this study clearly reveal that the SLL highly reduced at a very directive beamwidth.
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.
Circularly polarized microstrip antenna with reactive load design for wireles...BASIM AL-SHAMMARI
This paper presents a design of microstrip antenna for IEEE 802.11b and for IEEE 802.11g using a nearly square patch antenna, excited by a standard miniature adapter probe feed line. The patch and ground plain are separated by a substrate; the radiating patch is loaded by a central shorting pin and feeding probe loaded by a series capacitor. This antenna has wide bandwidth in the frequency band of (WLAN) and with a return loss ≤ −10 dB from 2.4 GHz to 2.48 GHz exhibits circularly polarized far field radiation pattern.
The proposed antennas have been simulated and analyzed using method of moments (MoM) based software package Microwave Office 2008 v8.0. The results show that the bandwidth of the antenna increases by using reactive load. The simulated gain of the antenna is over 6 dB.
Circularly polarized microstrip antenna with reactive load design for wireles...BASIM AL-SHAMMARI
Abstract
This paper presents a design of microstrip antenna for IEEE 802.11b and for IEEE 802.11g using a nearly square patch antenna, excited by a standard miniature adapter probe feed line. The patch and ground plain are separated by a substrate; the radiating patch is loaded by a central shorting pin and feeding probe loaded by a series capacitor. This antenna has wide bandwidth in the frequency band of (WLAN) and with a return loss ≤ −10 dB from 2.4 GHz to 2.48 GHz exhibits circularly polarized far field radiation pattern.
The proposed antennas have been simulated and analyzed using method of moments (MoM) based software package Microwave Office 2008 v8.0. The results show that the bandwidth of the antenna increases by using reactive load. The simulated gain of the antenna is over 6 dB.
This document describes the design of a patch antenna that can operate at multiple frequency bands using metamaterials. A rectangular patch antenna is designed to operate at 3 GHz. Then, a unit cell of complementary split-ring resonator (CSRR) is designed to also operate at 3 GHz. An array of this CSRR unit cell is placed on the patch to act as a metamaterial and enable multiband operation. Specifically, the antenna is designed to resonate in the Bluetooth, WiMax and Wi-Fi bands. Simulation results using HFSS software show that the proposed antenna provides good performance in terms of voltage standing wave ratio, return loss and impedance matching for multiband operation.
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).
This document discusses the performance analysis of a microstrip printed antenna conformed on a cylindrical body operating at a resonance frequency of 4.6 GHz for the TM01 mode. It begins with an introduction to microstrip antennas and the effects of curvature. It then presents mathematical models for the electric and magnetic fields, input impedance, return loss, and voltage standing wave ratio for a curved microstrip antenna. Results show the resonance frequency shifts 35 MHz as the radius of curvature changes from 6 mm to a flat antenna. Graphs also show the real and imaginary parts of input impedance vary with frequency for different radii of curvature.
13. Analysis of Half TEm horn type antenna for High power Impulse radiation a...Dr. SACHIN UMBARKAR
This document discusses the analysis and design of a half transverse electromagnetic (HTEM) horn-type antenna for high-power impulse radiation applications. It presents mathematical formulations for calculating key antenna parameters like characteristic impedance that consider the isolation distance between the antenna arm and reflector. Simulation and experimental results are used to determine the optimal geometric design parameters, such as tapering angle and flair angle, that maximize antenna gain. Formulas show how parameters like electric and magnetic fields depend on the antenna geometry, pulse characteristics, and material properties.
Comparative Analysis for Different Stack Shaped Microstrip Patch Antennaijsrd.com
A compact stack antenna consisting of square patch, loop couplers and inset feed line is reviewed in this work. This proposed design represents a stacked patch antenna having an arrangement of two substrates separated by an air gape and a coupling is provided using square loop structure. The structure is reviewed in two different directions firstly the feed arrangement is varied and secondly a variation in coupler structure is done to make the antenna work at multiple frequencies in UWB range. The simulation results of this work with different resonator structure and feed structures are presented and comparative analysis of these different arrangements is presented in this paper. Simulation results obtained from the proposed antenna for return loss, polar radiation and pattern voltage standing wave ratio (VSWR) shows its suitability for ultra wide band application.
T- Shape Antenna Design for Microwave Band Applications IJEEE
The document summarizes the design and simulation of a T-shaped fractal microstrip patch antenna for microwave band applications. The antenna was designed using a fractal technique with a scaling factor of 1/3 at each iteration to achieve multiband operation. Simulation results showed resonances at 2.4 GHz, 6.8 GHz, 8 GHz, 10.8 GHz, 12.2 GHz and 15.4 GHz with bandwidths ranging from 230 MHz to 2 GHz. The antenna exhibited VSWR less than 2 and gain higher than other resonant frequencies at 2.4 GHz, 8 GHz and 15.4 GHz. The fractal antenna design achieved size reduction and multiband performance making it suitable for applications such as wireless communications.
Some possible interpretations from data of the CODALEMA experimentAhmed Ammar Rebai PhD
The purpose of the CODALEMA experiment, installed at the Nan\c{c}ay Radio Observatory (France), is to study the radio-detection of ultra-high energy cosmic rays in the energy range of 10^{16}-10^{18} eV. Distributed over an area of 0.25 km^2, the original device uses in coincidence an array of particle detectors and an array of short antennas, with a centralized acquisition. A new analysis of the observable in energy for radio is presented from this system, taking into account the geomagnetic effect. Since 2011, a new array of radio-detectors, consisting of 60 stand-alone and self-triggered stations, is being deployed over an area of 1.5 km^2 around the initial configuration. This new development leads to specific constraints to be discussed in term of recognition of cosmic rays and in term of analysis of wave-front.
Extended-Bandwidth Microstrip Circular Patch Antenna for Dual Band Applications IJECEIAES
This paper presents a new wideband microstrip circular patch antenna (MCPA) fed by proximity-coupled line with double-stub matching to achieve dual-band operation. Bandwidth extension is achieved by exciting higherorder modes in the circular radiating patch, and using two stubs to achieve adequate matching across the obtained two bands. The characteristics of the antenna such as reflection coefficient, impedance bandwidth, gain and radiation pattern are investigated and optimized through parametric studies using the CST Microwave Studio Suite. The antenna achieved a large relative bandwidth of 45.16% at the upper band, while the lower one has 10.3% relative bandwidth. The maximum achieved gain of the dual-band antenna in the 5.8GHz band is 4.62dBi while it is 4.85dBi in the upper band. The antenna has an overall size of 30×30×3.2mm3 corresponding to 0.58λ × 0.58 λ × 0.062 λ at the lower band of 5.8 GHz. The proposed antenna should be useful for WLAN and X-band communication systems.
International Journal of Engineering Research and DevelopmentIJERD Editor
This document presents a technique for estimating parameters of a deployable mesh reflector antenna using 3D coordinate data and least squares fitting. It involves determining the unknown coefficients of the general quadratic surface equation that best fits the 3D points. The shape of the surface is then estimated as an elliptic paraboloid based on its invariants. Key parameters of the elliptic paraboloid like the focal length are then determined by reconstructing the surface in its standard form based on the estimated coefficients and orientations. Estimating these parameters at different stages of deployment testing can help validate the stability of the antenna surface and placement of its feed.
A Broadband Rectangular Microstrip Patch Antenna for Wireless Communicationswww.nbtc.go.th
In this paper, a simple design of wideband
rectangular patch antenna is presented by using asymmetrical
feed and a reduction in ground plane with proper gap distance.
The frequency-dependent characteristic impedance included in
the proposed procedure is addressed to eliminate possible
errors in the high-frequency broadband applications. The
antenna proposed in this research provides 2.3GHz bandwidth
(frequency range: 0.9GHz - 3.2GHz) which can be utilized in
various broadband applications such as remote sensing,
biomedical and mobile radio. The proposed procedure in this
research is compatible with CAD applications and is valuable
contribution as it permits quick and easy design for RF
engineers.
Reference : International Journal of Modeling and Optimization, Vol. 4, No. 3, June 2014
http://www.ijmo.org/papers/373-A0002.pdf
Thanks for reading.
Noppadol Tiamnara
LHCP four patches stack triangular truncated antenna using corporate feed mic...IJECEIAES
This document summarizes the design and simulation results of a left-hand circularly polarized (LHCP) array antenna consisting of four stacked triangular truncated microstrip patches for use in a CP-SAR sensor on an unmanned aerial vehicle. The antenna achieves a gain of 9.74 dBic, an axial ratio of 2.89 dB, a 410 MHz impedance bandwidth, and a 100 MHz 3 dB axial ratio bandwidth at the target frequency of 5.2 GHz. Simulation results show the antenna meets specifications for gain, axial ratio, efficiency, and beamwidths required for the CP-SAR application.
Microstrip patch antenna for pcs and wlaneSAT Journals
Abstract Due to development in wireless devices, it poses a new challenge for the design of an antenna in wireless communication. Patch antennas are well suited for various wireless application systems due to their low weight, low profile, versatility, conformability, low cost and low sensitivity to manufacturing tolerances. This paper present design, simulation of a rectangular micro strip antenna for WLAN and PCS. The aim of the work is to design reliable broadband, compact patch antenna for wireless devices. Antenna is proposed which is providing circular polarization, dual band, resonant frequencies at 1.9 GHz, 2.4 GHz. Key Words: Patch antenna, co-axial feeding, polarization, dual band, HFSS …
This document presents a new printed slot antenna design based on the first iteration of the Sierpinski gasket fractal geometry for dual band wireless communication applications. The antenna is fed by a microstrip transmission line and exhibits resonant behavior at 2.4 GHz and 5.2 GHz, making it suitable for dual band WLAN systems. Simulation results show the lower resonant band is determined by the slot size, while the feed length and position of a vertical stub affect the upper band matching and frequency. Parametric studies optimize the antenna for good impedance matching across both bands.
This document discusses using a genetic algorithm to optimize the resonant frequency of a coaxially fed rectangular microstrip antenna. The genetic algorithm optimizes patch length, width, and feed position at frequencies of 3GHz, 5GHz, and 10GHz. Results showed the optimized antennas had return losses of -18.7dB, -22.03dB, and -41.75dB respectively at the desired frequencies, indicating good impedance matching. Radiation patterns were also verified to show forward radiation and no backward radiation, validating the design accuracy. The use of genetic algorithms for antenna design optimization encourages accurate resonant frequency evaluation.
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.
1. The document describes a new design for a small microstrip antenna with variable band-notch filtering capabilities for super ultra-wideband applications including 5G networks and IoT.
2. The antenna achieves improved radiation patterns between 3-14 GHz through modifications to the patch, ground plane, and feed line. It also integrates a band-notch filter using a slot on the patch to reject interference from other wireless systems like WLAN.
3. The center frequency of the band-notch filter can be tuned from 3.5-6 GHz by adjusting the slot dimensions or using a variable capacitor. This allows the antenna to reject interference across different WLAN bands.
1. The document describes the design and simulation of a Defected Ground Structure (DGS) bandpass filter on a Rogers RT/duroid 6006 substrate.
2. The filter was designed to have a passband between 10-15 GHz. It was simulated using Ansoft HFSS and found to have good bandpass characteristics in that frequency range.
3. The DGS unit cells were arranged periodically in the ground plane to create a photonic bandgap, which improves the selectivity of the filter.
This document summarizes a research article that designed a compact, low weight, high gain broadband antenna using a polarization-rotation technique for X-band radar. Key points:
1) A cassegrain antenna was designed using grid wires instead of solid metal to reduce weight. A 4-horn array feed was used to create sum and difference patterns for target tracking.
2) The design placed the feed antenna at the vertex of the main parabolic reflector to reduce cable delays. It also used the left part of the hyperbolic subreflector to reduce size.
3) Simulation and measurement results showed the antenna achieved an average gain of 35 dB from 8.5-9.5 GHz, with over
This document describes the design and testing of a dual-polarized slot array patch antenna for WiMAX applications operating at 5.8 GHz. The antenna consists of an 8x8 array of circular patch elements, with each element excited using an aperture coupled microstrip feed. The design was optimized using simulation software to achieve high gain (26 dBi), wide bandwidth (14%), high port isolation, and good radiation patterns. Both simulated and measured results showed good agreement. The antenna meets specifications for WiMAX applications in the 5.15-5.9 GHz band and was found to be low-cost and easy to fabricate.
Advanced control scheme of doubly fed induction generator for wind turbine us...IJECEIAES
This paper describes a speed control device for generating electrical energy on an electricity network based on the doubly fed induction generator (DFIG) used for wind power conversion systems. At first, a double-fed induction generator model was constructed. A control law is formulated to govern the flow of energy between the stator of a DFIG and the energy network using three types of controllers: proportional integral (PI), sliding mode controller (SMC) and second order sliding mode controller (SOSMC). Their different results in terms of power reference tracking, reaction to unexpected speed fluctuations, sensitivity to perturbations, and resilience against machine parameter alterations are compared. MATLAB/Simulink was used to conduct the simulations for the preceding study. Multiple simulations have shown very satisfying results, and the investigations demonstrate the efficacy and power-enhancing capabilities of the suggested control system.
A review on techniques and modelling methodologies used for checking electrom...nooriasukmaningtyas
The proper function of the integrated circuit (IC) in an inhibiting electromagnetic environment has always been a serious concern throughout the decades of revolution in the world of electronics, from disjunct devices to today’s integrated circuit technology, where billions of transistors are combined on a single chip. The automotive industry and smart vehicles in particular, are confronting design issues such as being prone to electromagnetic interference (EMI). Electronic control devices calculate incorrect outputs because of EMI and sensors give misleading values which can prove fatal in case of automotives. In this paper, the authors have non exhaustively tried to review research work concerned with the investigation of EMI in ICs and prediction of this EMI using various modelling methodologies and measurement setups.
Harnessing WebAssembly for Real-time Stateless Streaming PipelinesChristina Lin
Traditionally, dealing with real-time data pipelines has involved significant overhead, even for straightforward tasks like data transformation or masking. However, in this talk, we’ll venture into the dynamic realm of WebAssembly (WASM) and discover how it can revolutionize the creation of stateless streaming pipelines within a Kafka (Redpanda) broker. These pipelines are adept at managing low-latency, high-data-volume scenarios.
Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...University of Maribor
Slides from talk presenting:
Aleš Zamuda: Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapter and Networking.
Presentation at IcETRAN 2024 session:
"Inter-Society Networking Panel GRSS/MTT-S/CIS
Panel Session: Promoting Connection and Cooperation"
IEEE Slovenia GRSS
IEEE Serbia and Montenegro MTT-S
IEEE Slovenia CIS
11TH INTERNATIONAL CONFERENCE ON ELECTRICAL, ELECTRONIC AND COMPUTING ENGINEERING
3-6 June 2024, Niš, Serbia
We have compiled the most important slides from each speaker's presentation. This year’s compilation, available for free, captures the key insights and contributions shared during the DfMAy 2024 conference.
ACEP Magazine edition 4th launched on 05.06.2024Rahul
This document provides information about the third edition of the magazine "Sthapatya" published by the Association of Civil Engineers (Practicing) Aurangabad. It includes messages from current and past presidents of ACEP, memories and photos from past ACEP events, information on life time achievement awards given by ACEP, and a technical article on concrete maintenance, repairs and strengthening. The document highlights activities of ACEP and provides a technical educational article for members.
A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMSIJNSA Journal
The smart irrigation system represents an innovative approach to optimize water usage in agricultural and landscaping practices. The integration of cutting-edge technologies, including sensors, actuators, and data analysis, empowers this system to provide accurate monitoring and control of irrigation processes by leveraging real-time environmental conditions. The main objective of a smart irrigation system is to optimize water efficiency, minimize expenses, and foster the adoption of sustainable water management methods. This paper conducts a systematic risk assessment by exploring the key components/assets and their functionalities in the smart irrigation system. The crucial role of sensors in gathering data on soil moisture, weather patterns, and plant well-being is emphasized in this system. These sensors enable intelligent decision-making in irrigation scheduling and water distribution, leading to enhanced water efficiency and sustainable water management practices. Actuators enable automated control of irrigation devices, ensuring precise and targeted water delivery to plants. Additionally, the paper addresses the potential threat and vulnerabilities associated with smart irrigation systems. It discusses limitations of the system, such as power constraints and computational capabilities, and calculates the potential security risks. The paper suggests possible risk treatment methods for effective secure system operation. In conclusion, the paper emphasizes the significant benefits of implementing smart irrigation systems, including improved water conservation, increased crop yield, and reduced environmental impact. Additionally, based on the security analysis conducted, the paper recommends the implementation of countermeasures and security approaches to address vulnerabilities and ensure the integrity and reliability of the system. By incorporating these measures, smart irrigation technology can revolutionize water management practices in agriculture, promoting sustainability, resource efficiency, and safeguarding against potential security threats.
CHINA’S GEO-ECONOMIC OUTREACH IN CENTRAL ASIAN COUNTRIES AND FUTURE PROSPECTjpsjournal1
The rivalry between prominent international actors for dominance over Central Asia's hydrocarbon
reserves and the ancient silk trade route, along with China's diplomatic endeavours in the area, has been
referred to as the "New Great Game." This research centres on the power struggle, considering
geopolitical, geostrategic, and geoeconomic variables. Topics including trade, political hegemony, oil
politics, and conventional and nontraditional security are all explored and explained by the researcher.
Using Mackinder's Heartland, Spykman Rimland, and Hegemonic Stability theories, examines China's role
in Central Asia. This study adheres to the empirical epistemological method and has taken care of
objectivity. This study analyze primary and secondary research documents critically to elaborate role of
china’s geo economic outreach in central Asian countries and its future prospect. China is thriving in trade,
pipeline politics, and winning states, according to this study, thanks to important instruments like the
Shanghai Cooperation Organisation and the Belt and Road Economic Initiative. According to this study,
China is seeing significant success in commerce, pipeline politics, and gaining influence on other
governments. This success may be attributed to the effective utilisation of key tools such as the Shanghai
Cooperation Organisation and the Belt and Road Economic Initiative.
2. 2 International Journal of Antennas and Propagation
r0
a
β
l
r0
a
h
x
z
Feed
Ground plane
Circular patch
Figure 1: Geometry of circular microstrip patch antenna.
S
Figure 2: Geometry of the array of circular microstrip patch ele-
ments.
wide, and each element provides low values of directiv-
ity. In many applications, it is necessary to design anten-
nas with very high-directive characteristics to meet the de-
mands of long-distance communications. This can only be
accomplished by increasing the electrical size of the antenna.
One way to enlarge the dimensions of the antenna without
necessarily increasing the size of the individual elements is
to form a set of the radiating elements in an electrical and
geometrical configuration. This new form of disposing el-
ement is designated array. After the rectangular patch, the
next most popular configuration is the circular patch or
disk.
2. MATERIALS AND METHODS
In this paper, an antenna array consisting of four equal cir-
cular elements with equal spacing, placed in the H-plane, has
been examined (Figures 1 and 2).
In Figure 2, the way of arranging circular patches and
feedings is shown (the antenna array is fed from its center).
They have the same phase in their entries considering the
shapes of feed lines for each of the circular patches.
2.1. Theory
In Figure 1, if h a and h λ, the analysis carried out by
Luk et al. [6] showed that, for the rectangular patch, the fields
under the cavity are essentially the same as the planar case. It
is reasonable to expect that this conclusion is independent
of the shape of the patch. For the circular patch, the radial
electrical fields of TM modes are given by [6]
Eρ = E0Jn knml cos n β − β0 , (1)
while Jm(x) is the Bessel function of the first kind of order m;
and knm is the root of Jn (knma) = 0 . Also, “a” that is shown
in Figure 1 is the diameter of each of the circular patches. The
value of β0 is determined by the position of the coaxial feed.
However, the resonant frequency is
fnm =
knmca
2πae
√
εr
, (2)
where c is the speed of light in free space; and ae is the effec-
tive radius that is given by
ae = a 1 +
2h
πaεr
ln
πa
2h
+ 1.7726
0.5
. (3)
Therefore, the resonant frequency of (2) for the dominant
TMz
110 should be expressed as
( fr)110 =
1.8412
2πae
√
εr
c. (4)
2.2. Design
For patch design, it is assumed that the dielectric constant of
the substrate (εr), the resonant frequency ( fr in Hz), and the
height of the substrate h (in cm) are known.
Design procedure
A first-order approximation to the solution of (3) for a is to
find ae using (4) and to substitute it into (3) for ae and a in
the logarithmic function. This will lead to
a =
F
1 + 2h/πεrF ln πF/2h + 1.7726
0.5 , (5)
where
F =
8.791 × 109
fr
√
εr
. (6)
The design of microstrip antenna is done as follows:
fr = 4.3 GHz, h = 0.16 cm, εr = 2.33. (7)
By substituting in (5), a J← 1.25cm.
Richards et al. have reported, calculated, and measured
values of the input impedance of a coaxial-feeding rectangu-
lar patch with εr J← 2.62 and h J← 2.62 cm [7]. For a coaxial
feed, matching the antenna impedance to the transmission-
line impedance can be accomplished simply by putting the
3. Asghar Keshtkar et al. 3
4.64.54.44.34.24.14
Frequency (GHz)
−8
−7
−6
−5
−4
−3
−2
−1
S21(dB)
Figure 3: Reflection coefficient as a function of frequency for cir-
cular microstrip antenna at 4.3 GHz.
feed at the proper location. In [8–11], some formulas have
been suggested for computing the input impedance in the
resonance state. Typically with very thin substrates, the feed
resistance is very smaller than resonance resistance, but in
thick substrates, the feed resistance is not negligible and
should be considered in impedance matching determining
the resonance frequency. In general, the input impedance is
complex, and it includes both a resonant part and a nonres-
onant part which is usually reactive. Both the real and imag-
inary parts of the impedance vary as a function of frequency.
Ideally, both the resistance and reactance exhibit symmetri-
cally about the resonant frequency, and the reactance at res-
onance is equal to the average of sum of its maximum value
(which is positive) and its minimum value (which is nega-
tive). A formula that has been suggested to approximate the
feed reactance, which does not take into account any images,
is [12]
xf = −
ηkh
2π
ln
kd
4
+ 0.577 , (8)
where d is the diameter of the feed probe.
Figure 3 shows the reflection coefficient as a function of
frequency simulated with HPHFSS 5.4 software. In the res-
onance state, the input impedance is a real value and has its
maximum quantity. It can be shown that coupling between
two patches, as coupling between two apertures or two wire
antennas, is a function of the position of one element relative
to the other [13–17]. For two circular microstrip patches, the
coupling for two side-by-side elements is a function of the
relative alignment (Figure 2). In Figure 4, the coupling value
that is measured for two cases in E-plane and H-plane is plot-
ted. In this figure, the measure of coupling is plotted versus
the distance between centers of two adjacent circular patches.
It can be seen that the coupling in H-plane is very small
in comparison with its value in E-plane. It is better to place
the elements of the antenna array in H-plane and we showed
3.22.82.421.61.20.80.40
Separation (wavelengths)
E-plane measured [11]
H-plane measured [11]
E-plane (first 16 modes)
H-plane (first 16 modes)
−50
−45
−40
−35
−30
−25
−20
−15
−10
Couplingmagnitude(dB)
Figure 4: Dominant mode mutual coupling for the conventional
circular microstrip patch antenna [13].
this in this paper. In the antenna discussed here, the spacing
between circular patches (s) is 3.8 cm. Considering that the
operating frequency is 4.3 GHz, the wavelength will be 7 cm.
Consequently, the value of s/λ is equal to 1.9, and then using
the plot in Figure 4, the value of coupling is about −30 dB,
that is very small and negligible.
3. RESULTS AND DISCUSSION
3.1. Numerical results and simulation
The aim of this project is to develop an antenna with a di-
rectional pattern and a gain at least equal to 12 dB. An an-
tenna array with equal spacing and uniform excitation was
designed. The circular microstrip antenna was simulated by
Ansoft Ensemble 8 that is based on the method of moment.
For obtaining pattern of this antenna array (N = 4), we have
the following [18]:
AF = A0
sin(Nψ/2)
N sin(ψ/2)
= A0
sin(2ψ)
4sin(ψ/2)
, (9)
ψ = α + βd sin(θ)cos(ϕ), (10)
βd =
2π
λ
(s) =
2π
7
(3.8) = π. (11)
Here, α = 0 is the phase difference between elements.
Figure 5 shows the array factor. The first null beam width is
[18]
BWFN = 2
2λ
Nd
= 2
2 × 7 × 10−2
4 × 3.8 × 10−2 = 115◦
,
HPBW = 2 0.886
λ
Nd
= 2 0.886
7 × 10−2
4 × 3.8 × 10−2 = 76◦
,
(12)
4. 4 International Journal of Antennas and Propagation
240
210
180
150
120
90
60
30
0
330
300
270
1
0.8
0.6
0.4
0.2
(a)
(b)
Figure 5: Array factor for 4 linear elements [18]: (a) H-plane cut
and (b) 3D pattern.
where AF in (9) is the array factor and beta = (2∗pi/lambda),
where lambda is the wavelength. “HPBW” is the half-power-
beam width, and “BWFN” is the beam width between first
nulls.
These quantities are used to obtain a whole antenna pat-
tern by considering the pattern of a circular microstrip ele-
ment. The pattern is almost symmetric (in both E-plane and
H-plane), and side lobes are very small (Figure 6). A plot of
the directivity of the dominant TMz
110 mode as a function of
the radius of the disk is shown in Figure 7. The measurement
of antenna parameters by theoretical calculations is some-
how difficult, but we can calculate them easily by softwares,
such as HPHFSS. In general, the dependence of antenna pa-
rameters to their physical parameters can be mentioned. The
bandwidth is inversely proportional to
√
εr. As we know, the
total directivity is equal to multiplication of patch directivity
and to the array directivity. From the diagrams in Figures 5
and 7, the value of directivity factor of circular microstrip an-
tenna is about 5 dB, and then a directivity of 13 dB at 4.3 GHz
330
300
270
240
210
180
150
120
90
60
30
0
50 40 30 20 10
H-plane
E-plane
Figure 6: Computed (based on moment method and cavity mod-
els) E-plane and H-plane patterns of circular microstrip patch an-
tenna: E-plane (φ = 0◦
,180◦
), H-plane (φ = 90◦
,270◦
).
10.90.80.70.60.50.40.30.20.10
ae/λ0
4
6
8
10
12
D0(dB)
Figure 7: Directivity versus effective radius for circular microstrip
patch antenna operating in dominant TMz
110 mode [12].
is achieved with the main lobe in the broadside direction,
with the 50-degree HPBW, and 25 dB SLL below the main
lobe.
The circular microstrip patch array antenna was simu-
lated by Ansoft Ensemble 8 and is shown in Figure 6.
In contribution to our discussion, we consider the results
of the simulation. In the analysis of this antenna by HPHFSS
software, three-dimensional pattern of this antenna is ob-
tained. It is shown in Figure 8, and its pattern in E-plane and
H-plane is also shown in Figure 9.
Considering the obtained value of input impedance by
HPHFSS software, we can obtain the matching impedance by
Microwave Office software (or analytic methods). Consider-
ing the feed lines, the circular patches have the same phase
at their entries, as can be seen in Figure 2, we specify the
impedance in each line by varying the width of lines until
5. Asghar Keshtkar et al. 5
240
210
180
150
120
90 60
30
330
300
270
0
302418126
30 24 18 12 6
(a)
330
300
270
240
210100
150
120
90
60 030
12
18
24
30
(b)
Figure 8: Three-dimensional pattern of the array antenna with the
circular microstrip patches simulated with the HPHFSS 5.4: (a) φ =
0◦
, (b) φ = 90◦
.
330
300
270
240
210
180
150
120
90
60
30
0
60
40
20
H-plane
E-plane
Figure 9: E-plane and H-plane patterns of the array antenna with
the circular microstrip patches simulated with the HPHFSS 5.4.
4.64.54.44.34.24.14
Frequency (GHz)
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
VSWR
Figure 10: VSWR as a function of frequency simulated by Mi-
crowave Office.
4.64.54.44.34.24.14
Frequency (GHz)
−25
−20
−15
−10
−5
0
S21(dB)
Figure 11: Reflection coefficient versus frequency of the array
antenna with the circular microstrip patches simulated with the
HPHFSS 5.4.
we obtain the amount of input impedance equal to 50 Ω.
The value of VSWR for this antenna that is obtained by Mi-
crowave Office software is shown in Figure 10, and the value
of reflection coefficient that is obtained by HPHFSS soft-
ware is shown in Figure 11. Regarding the simulation with
HPHFSS 5.4 software, the input impedance of the antenna is
55 + 25j, and so we have
|Γ| =
Zl − Z0
Zl + Z0
= 0.2362 = −12.5dB,
VSWR =
1 + |Γ|
1 − |Γ|
= 1.6.
(13)
3.2. Array antenna configuration
The array antenna was constructed as shown in Figure 12.
The dimensions and structural diagram of the antenna are
shown too in this figure. The fabricated patch was designed
to operate at 4.3 GHz. The patch is probe feeding, and the
ground plane is finite for this patch and has the dimensions
of 15
m
=←4 cm. By selecting proper values for microstrip-line
width and length and the position of the feed point, a good
6. 6 International Journal of Antennas and Propagation
W1
W2 W3
W4
W5
W6
L1 L2
Figure 12: Pictures of the fabricated antenna and its geometry. The
feeding line is a standard 50Ω coaxial probe feed. Other dimensions
are W1 = 0.4cm, W2 = 0.6cm, W3 = 0.3cm, W4 = 0.5cm, W5 =
0.6cm, W6 = 0.2cm, L1 = 3cm, L2 = 1.9cm.
330
300240
270
210
180
150
120
90 30
60
30
0
10
20
E-plane
H-plane
4200 MHz
4300 MHz
4400 MHz
K.N Toosi Univ. of Tech. Telecom. Dept. Prof. Morshed Ant. Lab.
Mstp ant. 01 H-plane & E-plane pattern #Date 83/10/22
Figure 13: Measured E-plane and H-plane patterns of the array an-
tenna with the circular microstrip patches.
impedance bandwidth can be obtained. An inset feed scheme
is employed to match the patch antenna to a 50Ω coaxial
probe feed. The dielectric material has a permittivity of 2.33
and a thickness of 0.16 cm. The substrate of this antenna
is made of RT/Duroid 5870, fabricated by Rogers Company
(Mentor, OH, USA).
3.3. Results of the test
In the test process, the antenna pattern and the value of
VSWR were obtained. Antenna radiation performance was
measured and recorded in two orthogonal principal planes
(E-plane and H-plane or vertical and horizontal planes). The
pattern was plotted in the form of polar coordinates. By def-
inition, near-field tests are done by sampling the field very
4.84.64.44.243.8
Frequency (GHz)
1
2
3
4
5
6
7
8
9
VSWR
Frequency = 4.4GHz
VSWR = 2.1483
Frequency = 4.3GHz
VSWR = 1.5433
Frequency = 4.205GHz
VSWR = 1.2775
Figure 14: VSWR as a function of frequency measured by the AGI-
LENT 8510C network analyzer.
close to the antenna on a known surface. From the phase and
amplitude data collections, the far-field pattern was com-
puted in the same fashion that theoretical patterns were com-
puted from the theoretical field distributions. The transfor-
mation used in the computation depends on the shape of
the surface over which the measurements are taken with the
scanning probe. An antenna range instrumentation must be
designed to operate over a wide range of frequencies, and it
usually can be classified into five categories as follows:
(1) source antenna and transmitting system,
(2) receiving system,
(3) positioning system,
(4) recording system,
(5) data-processing system.
This technique involves an antenna under test which is placed
on a rotational positioned and rotated around the azimuth
to generate a two-dimensional polar pattern. This measure-
ment was done for the two principal axes of the antenna to
determine parameters such as antenna beam width in both
the E- and H-planes. The practical results of the test are in
agreement with the desirable results and theoretical analy-
sis. E-plane and H-plane patterns of the antenna are shown
in Figure 13. In the practical test carried out by AGILENT
8510C network analyzer, the value of VSWR in central fre-
quency was 1.5433 that was well in agreement with the the-
oretical analysis (Figure 14). Variation in the measured per-
formance is mainly due to imprecise fabrication by a milling
machine. It is important to calibrate the network analyzer
before doing VSWR measurement. The network analyzer
should be calibrated for a suitable frequency range contain-
ing the band where the antenna will operate. Typical network
analyzers have a cable with SMA connector in the end. Cal-
ibration was performed by connecting three known termi-
nations, 50 Ω load, short, and open, to this SMA connector.
After calibration the reference plane will be at the connection
point of the SMA connector. To measure the reflection at the
feed point of the antenna, a semirigid coax cable with SMA
connector in one end can be used.
7. Asghar Keshtkar et al. 7
4. CONCLUSION
A small microstrip patch antenna array has been presented.
The antenna has been designed to be used in altimeter sys-
tem applications, in the C-band. In fact, this antenna was
designed for 4.3 GHz and 12 dB gain. But as you can see,
4.2 GHz also has good pattern and proper VSWR. The de-
sign has been accomplished using commercially available
HPHFSS, Ansoft Ensemble 8, and Microwave Office 2006
softwares. The designed antenna has shown good perfor-
mance in terms of return losses and radiation (a proto-
type has been fabricated and tested). Good agreement has
been obtained between simulation and experimental results,
providing validation of the design procedure. Good perfor-
mance has been obtained for the envisaged applications.
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