Microstrip antennas are low-profile antennas that are utilized in wireless communication systems.In recent years,communication engineers have been increasingly interested in it.Because of downsizing,novelty,and cost re...Microstrip antennas are low-profile antennas that are utilized in wireless communication systems.In recent years,communication engineers have been increasingly interested in it.Because of downsizing,novelty,and cost reduction,the number of wireless standards has expanded in recent years.Wideband tech-nologies have evolved in addition to analog and digital services.Radars necessi-tate antenna subsystems that are low-profile and lightweight.Microstrip antennas have these qualities and are suited for radars as an alternative to the bulky and heavyweight reflector/slotted waveguide array antennas.A perforated corner single-line fed microstrip antenna is designed here.When compared to the basic square microstrip antenna,this antenna has better specifications.Because key issue is determining the best values for various antenna parameters when devel-oping the patch antenna.Optimized Neural Network(ONN)is one potential tech-nique utilized to solve this issue,and this work also uses Particle Swarm Optimization(PSO)to enhance the antenna performance.Return loss(S11)and Voltage Standing Wave Ratio(VSWR)parameters are considered in all situations,developed with Advanced Design System(ADS)applications.The transmitters are made to emit in the Ku-band,which covers a wide range of wavelengths.From 5–15 GHz,it is used in most current radars.The ADS suite is used to create the simulation design.展开更多
In the past twenty years, electromagnetic metamaterials represented by left-handed metamaterials(LHMs) have attracted considerable attention due to the unique properties such as negative refraction, perfect lens, an...In the past twenty years, electromagnetic metamaterials represented by left-handed metamaterials(LHMs) have attracted considerable attention due to the unique properties such as negative refraction, perfect lens, and electromagnetic cloaks. In this paper, we present a comprehensive review of our group's work on metamaterials and metasurfaces. We present several types of LHMs and chiral metamaterials. As a two-dimensional equivalent of bulk three-dimensional metamaterials, metasurfaces have led to a myriad of devices due to the advantages of lower profile, lower losses, and simpler to fabricate than bulk three-dimensional metamaterials. We demonstrate the novel microwave metadevices based on metamaterials and metasurfaces: perfect absorbers and microwave patch antennas, including novel transmission line antennas,high gain resonant cavity antennas, wide scanning phased array antennas, and circularly polarized antennas.展开更多
Wireless interrogation of a rectangular microstrip patch antenna for strain measurement is investigated by simulations.To analyze the antenna performance,a microstrip line-feeding patch antenna at 10 GHz is designed.A...Wireless interrogation of a rectangular microstrip patch antenna for strain measurement is investigated by simulations.To analyze the antenna performance,a microstrip line-feeding patch antenna at 10 GHz is designed.A patch antenna wirelessly fed by a horn is proposed to measure the strain.The direction information of strain detected by the patch antenna is also considered.The strain can be detected both in the width and length directions.It is shown that the strain can be measured wirelessly using a standard horn antenna.This kind of wireless strain-sensing technique offers significant potential for wireless structural health monitoring(SHM),especially for high-end equipment.展开更多
A novel compact Swastika shaped patch antenna is designed in the present work,which can be used for Multiple Input Multiple Output(MIMO) systems.The proposed two element MIMO system resonates at a triband of 3.3 GHz,5...A novel compact Swastika shaped patch antenna is designed in the present work,which can be used for Multiple Input Multiple Output(MIMO) systems.The proposed two element MIMO system resonates at a triband of 3.3 GHz,5.8 GHz,and 7.1 GHz with an improved impedance bandwidth of 37% and a reduced mutual coupling of-33 dB.These results are better compared to a normal E shaped patch antenna designed with same size and thickness,achieved without using any additional decoupling methods.A 2×2 MIMO system employing the Swastika shaped patch antennas is analyzed using computational electromagnetic ray tracing software for an indoor environment.The results show an improvement in the capacity compared to a 2×2 MIMO system developed with dipole antennas.The proposed antenna is a good choice for MIMO systems operating for several Ultra WideBand(UWB) applications.展开更多
Every new generation of antennas is characterized by increased accuracy and faster transmission speeds.However,patch antennas have been known to damage human health.This type of antenna sends out electromagnetic waves...Every new generation of antennas is characterized by increased accuracy and faster transmission speeds.However,patch antennas have been known to damage human health.This type of antenna sends out electromagnetic waves that increase the temperature of the human head and prevent nerve strands from functioning properly.This paper examines the effect of the communication between the patch antenna and the brain on the head’s temperature by developing a hypothetical multi-input model that achieves more accurate results.These inputs are an individual’s blood and tissue,and the emission power of the antenna.These forces depend on the permeability and conductivity characteristics of the metal from which the antenna is fabricated.The proposed model is the first one that links the material the antenna is manufactured from and the head’s temperature.The results show that there are only a small number of materials that should be used as antenna covers.These materials are in the form of thin films.By using these thin films at different temperatures,the risk to the head can be reduced.This paper finds that the best results were obtained when the patch antenna was made of one of the following materials operating at a specific temperature:traditional materials at 305°K;casting cast steel at around 295°K;bismuth telluride(Bi2Te3)at 290°K;or barium sodium niobate at 310°K.展开更多
This research investigates a monopole patch antenna for Wi-Fi applications at 2.45 and 5.2 GHz,and WiMax at 3.5 GHz.A low-cost and flexible graphite sheet with good conductivity,base on graphite conductive powder and ...This research investigates a monopole patch antenna for Wi-Fi applications at 2.45 and 5.2 GHz,and WiMax at 3.5 GHz.A low-cost and flexible graphite sheet with good conductivity,base on graphite conductive powder and glue is used to create a radiator patch and ground plane.Instead of commercially available conductive inks or graphite sheets,we use our selfproduced graphite liquid to create the graphite sheet because it is easy to produce and inexpensive.The antenna structure is formed using a low-cost and easy hand-screen printing approach that involved placing graphite liquid on a bendable polyester substrate.This research focuses on designing and developing a low-cost,thin,light,and flexible patch antenna for wireless communication and smart glass applications.The proposed antenna utilizes CST microwave software for simulations to improve the parameters before fabrication and measurement.The simulation and measurement results for the reflection coefficients at 2.45 GHz,3.5 GHz,and 5.20 GHz are reliable and cover the required resonance frequencies,antennas gain are 1.91,1.98,and 1.87 dB,respectively.Additionally,the radiation patterns of both results are omnidirectional.In the experiments,bending the proposed patch antenna along with the cylinder with the radii of 60,40,and 25 mm yielded the same measurement results as the unbent patch antenna.展开更多
A novel low radar cross-section(RCS)and high gain patch antenna array is proposed.A pair of slots introduced on the mushroom electromagnetic bandgap(EBG)patch realize polarization-dependency and act as parasitic radia...A novel low radar cross-section(RCS)and high gain patch antenna array is proposed.A pair of slots introduced on the mushroom electromagnetic bandgap(EBG)patch realize polarization-dependency and act as parasitic radiation to enhance the antenna gain.A chessboard-like configuration composed of slot-EBG blocks is further equipped on the antenna array for scattering cancellation.Optimizing the layout pattern enables the designing of a high-gain and low-RCS antenna array using the slot-EBGs.Full-wave simulations validate that a front gain enhancement of more than 2.5.dB in the operating frequency band and low-RCS in a broad frequency band for normal incidence are obtained by the proposed antenna array.展开更多
Ring patch antennas have the characteristics of electrically small size as decreasing the width of the conducting portion compared to those of conventional patch antennas.In the ring patch antenna,using capacitive fee...Ring patch antennas have the characteristics of electrically small size as decreasing the width of the conducting portion compared to those of conventional patch antennas.In the ring patch antenna,using capacitive feed method is suitable for impedance matching.The effect of the size of the feed patch on the input impedance of the square ring patch antennas are analyzed and radiation patterns of the square ring patch antennas are compared to that of a square conventional patch antenna by the simulated results.展开更多
The spectral domain integral equation(SDIE) provides an accurate and efficient method for computing the resonant frequency, radiation patterns, etc . Using continuous Fourier transform, the formulation utilizes the...The spectral domain integral equation(SDIE) provides an accurate and efficient method for computing the resonant frequency, radiation patterns, etc . Using continuous Fourier transform, the formulation utilizes the singular integral equations via the Glerkin's method to derive the deterministic equation with fewer mathematical manipulations. In contrast, discrete Fourier transform(DFT) requires intricate mathematical labor. The present scheme requires a small size, i.e ., (2×2) matrix, and it is possible to extract higher order modal solutions conveniently. Moreover, computation is reduced with the same convergence properties. Based on the present scheme, some results for resonant frequency and radiation patterns compared with available data and computed current distribution on the patch are presented.展开更多
A new photonic bandgap (PBG) cover for a patch antenna with a photonic bandgap substrate is introduced. The plane wave expansion method and the FDTD method were used to calculate such an antenna system. Numerical re-s...A new photonic bandgap (PBG) cover for a patch antenna with a photonic bandgap substrate is introduced. The plane wave expansion method and the FDTD method were used to calculate such an antenna system. Numerical re-sults for the input return loss, radiation pattern, surface wave, and the directivity of the antennas are presented. A com-parison between the conventional patch antenna and the new PBG antenna is given. It is shown that the new PBG cover is very efficient for improving the radiation directivity. The physical reasons for the improvement are also given.展开更多
A metamaterial was introduced into the cover of a patch antenna and its band structure was analyzed. The metama- terial cover with correct selection of the working frequency increases by 9.14 dB the patch antenna’s d...A metamaterial was introduced into the cover of a patch antenna and its band structure was analyzed. The metama- terial cover with correct selection of the working frequency increases by 9.14 dB the patch antenna’s directivity. The mechanism of metamaterial cover is completely different from that of a photonic bandgap cover. The mechanism of the metamaterial cover, the number of the cover’s layers, and the distance between the layers, were analyzed in detail. The results showed that the metamaterial cover, which works like a lens, could effectively improve the patch antenna’s directivity. The physical reasons for the improvement are also given.展开更多
A new patch antenna system with a metamaterial cover is presented in this paper. The impedance, radiation pattern, and directivity of such an antenna are studied. A performance comparison between the conventional patc...A new patch antenna system with a metamaterial cover is presented in this paper. The impedance, radiation pattern, and directivity of such an antenna are studied. A performance comparison between the conventional patch antenna and the new metamaterial patch antenna is given. The results show that the directivity of the metamaterial patch antenna is significantly im- proved. The effect of the metamaterial cover’s layer numbers on the radiation pattern of the patch antenna is also studied.展开更多
Different feeding techniques of microstrip patch antennas with different spiral defected ground structures are presented in this paper. The investigated structures illustrate some merits in designing multi-electromagn...Different feeding techniques of microstrip patch antennas with different spiral defected ground structures are presented in this paper. The investigated structures illustrate some merits in designing multi-electromagnetic band-gap structures by adjusting the capacitance and changing the inductance through varying the width and length of spiral defected ground structure. Then by applying the three different spirals shapes (one, two and four arms) as the ground plane of microstrip patch antenna with different feeding techniques to create multi or ultra wide-band, improve the antenna gain and reduce the antenna size, it is found that the four arms spiral defected ground structure of microstrip patch antenna with offset feed gives good performance, electrical size reduction to about 75% as compared to the original patch size and ultra-wide bandwidth extends from 2 GHz up to 12 GHz with ?8 dB impedance bandwidth.展开更多
The finite element modeling of three dimensional structures is important for researchers especially in the field of antennas and other domains of electromagnetic waves. This paper presents a finite element calculation...The finite element modeling of three dimensional structures is important for researchers especially in the field of antennas and other domains of electromagnetic waves. This paper presents a finite element calculations and numerical analysis for the microstrip patch antennas. In this paper, two different designs have been modelled and analyzed and both designs are based on the rectangular patches. The feeding point of one design is inside the patch while the other design contains feeding point outside the patch is T shaped. The computational analysis showed some interesting results for radiation pattern and far field domain. For these designs, the characteristic impedance taken is 50 Ω and the operating frequency domain is 1.4 to 1.7 GHz. The microstrip patch antennas are encapsulated in the inert spherical atmosphere of 20 mm thickness containing air inside it.展开更多
This paper presents the design of a fully packaged 60 GHz wideband patch antenna incorporating an air cavity and a fused silica superstrate. Circular polarization (CP) is realized by introducing a diagonal slot at the...This paper presents the design of a fully packaged 60 GHz wideband patch antenna incorporating an air cavity and a fused silica superstrate. Circular polarization (CP) is realized by introducing a diagonal slot at the center of the square patch. By optimizing the patch and the slot dimensions, a high efficiency (>90%) microstrip fed CP antenna with an impedance bandwidth of 24% and a 6 dB axial ratio bandwidth of 21.5% is designed. A coplanar waveguide (CPW) to microstrip transition with λ/4-open-ended stubs are then designed to match the antenna to the CPW packaging interface. The experimental results of the final packaged antenna agree reasonably with the simulation results, demonstrating an impedance bandwidth of more than 26% and a 6 dB axial ratio bandwidth of 22.7%.展开更多
A single layer triangular patch antenna fed by an L-shaped probe was investigated numerically by using FDTD (Finite Difference Time Domain) method. It achieves >40% impedance bandwidth (VSWR<2) and stable radiat...A single layer triangular patch antenna fed by an L-shaped probe was investigated numerically by using FDTD (Finite Difference Time Domain) method. It achieves >40% impedance bandwidth (VSWR<2) and stable radiation pattern across the passband. The triangular patch antenna with two orientations of L-shaped probe has almost the same characteristics, such as impedance bandwidth and radiation pattern. The bandwidth vs feeding position was also investigated, the broadband characteristic can be observed when the feeding position is only in a small segment along the centerline.展开更多
A new multi-species particle swarm optimization with a two-level hierarchical topology and the orthogonal learning strategy(OMSPSO) is proposed, which enhances the global search ability of particles and increases thei...A new multi-species particle swarm optimization with a two-level hierarchical topology and the orthogonal learning strategy(OMSPSO) is proposed, which enhances the global search ability of particles and increases their convergence rates. The numerical results on 10 benchmark functions demonstrated the effectiveness of our proposed algorithm. Then, the proposed algorithm is presented to design a butterfly-shaped microstrip patch antenna. Combined with the HFSS solver, a butterfly-shaped patch antenna with a bandwidth of about 40.1% is designed by using the proposed OMSPSO. The return loss of the butterfly-shaped antenna is greater than 10 d B between 4.15 and 6.36 GHz. The antenna can serve simultaneously for the high-speed wireless computer networks(5.15–5.35 GHz) and the RFID systems(5.8 GHz).展开更多
A patch antenna and our proposed metamaterial patch antenna are simulated and compared. A high gain patch antenna using a single layer metamaterial superstrate with a near to zero refractive index(n)is proposed.The si...A patch antenna and our proposed metamaterial patch antenna are simulated and compared. A high gain patch antenna using a single layer metamaterial superstrate with a near to zero refractive index(n)is proposed.The simulation results provide that the gain of the proposed antenna is increased by about 7dB. Consequently,the high gain antenna can be easily obtained by using our metamaterial superstrate.展开更多
Antenna is very crucial to radiotelemetry capsules which can measure the physiological parameters of the gastroin- testinal (GI) tract. The objective of this paper is to design a novel spiral slots microstrip patch an...Antenna is very crucial to radiotelemetry capsules which can measure the physiological parameters of the gastroin- testinal (GI) tract. The objective of this paper is to design a novel spiral slots microstrip patch antenna for the radiotelemetry capsules communicating with external recorder at 915 MHz located in ISM (Industry, Science, and Medical) bands. The microstrip patch antenna is designed and evaluated using the finite-difference time-domain (FDTD) method. Return loss characteristics and the effect of the human body on resonant frequency are analyzed, and the performances of radiation patterns at different positions of the human alimentary tract are also estimated. Finally, specific absorption rate (SAR) computations are performed, and the peak 1-g and 10-g SAR values are calculated. According to the peak SAR values, the maximum delivered power for the designed antenna was found so that the SAR values of the antenna satisfy the ANSI (American National Standards Institute) limitations.展开更多
文摘Microstrip antennas are low-profile antennas that are utilized in wireless communication systems.In recent years,communication engineers have been increasingly interested in it.Because of downsizing,novelty,and cost reduction,the number of wireless standards has expanded in recent years.Wideband tech-nologies have evolved in addition to analog and digital services.Radars necessi-tate antenna subsystems that are low-profile and lightweight.Microstrip antennas have these qualities and are suited for radars as an alternative to the bulky and heavyweight reflector/slotted waveguide array antennas.A perforated corner single-line fed microstrip antenna is designed here.When compared to the basic square microstrip antenna,this antenna has better specifications.Because key issue is determining the best values for various antenna parameters when devel-oping the patch antenna.Optimized Neural Network(ONN)is one potential tech-nique utilized to solve this issue,and this work also uses Particle Swarm Optimization(PSO)to enhance the antenna performance.Return loss(S11)and Voltage Standing Wave Ratio(VSWR)parameters are considered in all situations,developed with Advanced Design System(ADS)applications.The transmitters are made to emit in the Ku-band,which covers a wide range of wavelengths.From 5–15 GHz,it is used in most current radars.The ADS suite is used to create the simulation design.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11674267,51272215,11874301,and 11204241)the National Basic Research Program of China(Grant No.2012CB921503)+2 种基金the National Aerospace Science Foundation of China(Grant No.2016ZF53061)the Fundamental Research Funds for the Central Universities,China(Grant No.3102017jghk02004)the Natural Science Basic Research Plan in Shaanxi Province of China(Grant No.2017JM1009)
文摘In the past twenty years, electromagnetic metamaterials represented by left-handed metamaterials(LHMs) have attracted considerable attention due to the unique properties such as negative refraction, perfect lens, and electromagnetic cloaks. In this paper, we present a comprehensive review of our group's work on metamaterials and metasurfaces. We present several types of LHMs and chiral metamaterials. As a two-dimensional equivalent of bulk three-dimensional metamaterials, metasurfaces have led to a myriad of devices due to the advantages of lower profile, lower losses, and simpler to fabricate than bulk three-dimensional metamaterials. We demonstrate the novel microwave metadevices based on metamaterials and metasurfaces: perfect absorbers and microwave patch antennas, including novel transmission line antennas,high gain resonant cavity antennas, wide scanning phased array antennas, and circularly polarized antennas.
基金supported by the National Natural Science Foundation of China (Nos. 51575015,51235001,51505013)
文摘Wireless interrogation of a rectangular microstrip patch antenna for strain measurement is investigated by simulations.To analyze the antenna performance,a microstrip line-feeding patch antenna at 10 GHz is designed.A patch antenna wirelessly fed by a horn is proposed to measure the strain.The direction information of strain detected by the patch antenna is also considered.The strain can be detected both in the width and length directions.It is shown that the strain can be measured wirelessly using a standard horn antenna.This kind of wireless strain-sensing technique offers significant potential for wireless structural health monitoring(SHM),especially for high-end equipment.
文摘A novel compact Swastika shaped patch antenna is designed in the present work,which can be used for Multiple Input Multiple Output(MIMO) systems.The proposed two element MIMO system resonates at a triband of 3.3 GHz,5.8 GHz,and 7.1 GHz with an improved impedance bandwidth of 37% and a reduced mutual coupling of-33 dB.These results are better compared to a normal E shaped patch antenna designed with same size and thickness,achieved without using any additional decoupling methods.A 2×2 MIMO system employing the Swastika shaped patch antennas is analyzed using computational electromagnetic ray tracing software for an indoor environment.The results show an improvement in the capacity compared to a 2×2 MIMO system developed with dipole antennas.The proposed antenna is a good choice for MIMO systems operating for several Ultra WideBand(UWB) applications.
基金This research was funded by King Khalid University—KSA,grant number(R.G.P.2/35/40)and the APC was funded by King Khalid University—KSA.
文摘Every new generation of antennas is characterized by increased accuracy and faster transmission speeds.However,patch antennas have been known to damage human health.This type of antenna sends out electromagnetic waves that increase the temperature of the human head and prevent nerve strands from functioning properly.This paper examines the effect of the communication between the patch antenna and the brain on the head’s temperature by developing a hypothetical multi-input model that achieves more accurate results.These inputs are an individual’s blood and tissue,and the emission power of the antenna.These forces depend on the permeability and conductivity characteristics of the metal from which the antenna is fabricated.The proposed model is the first one that links the material the antenna is manufactured from and the head’s temperature.The results show that there are only a small number of materials that should be used as antenna covers.These materials are in the form of thin films.By using these thin films at different temperatures,the risk to the head can be reduced.This paper finds that the best results were obtained when the patch antenna was made of one of the following materials operating at a specific temperature:traditional materials at 305°K;casting cast steel at around 295°K;bismuth telluride(Bi2Te3)at 290°K;or barium sodium niobate at 310°K.
基金This work was supported by the RMUTT research and development fund。
文摘This research investigates a monopole patch antenna for Wi-Fi applications at 2.45 and 5.2 GHz,and WiMax at 3.5 GHz.A low-cost and flexible graphite sheet with good conductivity,base on graphite conductive powder and glue is used to create a radiator patch and ground plane.Instead of commercially available conductive inks or graphite sheets,we use our selfproduced graphite liquid to create the graphite sheet because it is easy to produce and inexpensive.The antenna structure is formed using a low-cost and easy hand-screen printing approach that involved placing graphite liquid on a bendable polyester substrate.This research focuses on designing and developing a low-cost,thin,light,and flexible patch antenna for wireless communication and smart glass applications.The proposed antenna utilizes CST microwave software for simulations to improve the parameters before fabrication and measurement.The simulation and measurement results for the reflection coefficients at 2.45 GHz,3.5 GHz,and 5.20 GHz are reliable and cover the required resonance frequencies,antennas gain are 1.91,1.98,and 1.87 dB,respectively.Additionally,the radiation patterns of both results are omnidirectional.In the experiments,bending the proposed patch antenna along with the cylinder with the radii of 60,40,and 25 mm yielded the same measurement results as the unbent patch antenna.
基金National Natural Science Foundation of China(U1730102)the National Key R&D Program of China(2017YFB0202500)。
文摘A novel low radar cross-section(RCS)and high gain patch antenna array is proposed.A pair of slots introduced on the mushroom electromagnetic bandgap(EBG)patch realize polarization-dependency and act as parasitic radiation to enhance the antenna gain.A chessboard-like configuration composed of slot-EBG blocks is further equipped on the antenna array for scattering cancellation.Optimizing the layout pattern enables the designing of a high-gain and low-RCS antenna array using the slot-EBGs.Full-wave simulations validate that a front gain enhancement of more than 2.5.dB in the operating frequency band and low-RCS in a broad frequency band for normal incidence are obtained by the proposed antenna array.
文摘Ring patch antennas have the characteristics of electrically small size as decreasing the width of the conducting portion compared to those of conventional patch antennas.In the ring patch antenna,using capacitive feed method is suitable for impedance matching.The effect of the size of the feed patch on the input impedance of the square ring patch antennas are analyzed and radiation patterns of the square ring patch antennas are compared to that of a square conventional patch antenna by the simulated results.
文摘The spectral domain integral equation(SDIE) provides an accurate and efficient method for computing the resonant frequency, radiation patterns, etc . Using continuous Fourier transform, the formulation utilizes the singular integral equations via the Glerkin's method to derive the deterministic equation with fewer mathematical manipulations. In contrast, discrete Fourier transform(DFT) requires intricate mathematical labor. The present scheme requires a small size, i.e ., (2×2) matrix, and it is possible to extract higher order modal solutions conveniently. Moreover, computation is reduced with the same convergence properties. Based on the present scheme, some results for resonant frequency and radiation patterns compared with available data and computed current distribution on the patch are presented.
文摘A new photonic bandgap (PBG) cover for a patch antenna with a photonic bandgap substrate is introduced. The plane wave expansion method and the FDTD method were used to calculate such an antenna system. Numerical re-sults for the input return loss, radiation pattern, surface wave, and the directivity of the antennas are presented. A com-parison between the conventional patch antenna and the new PBG antenna is given. It is shown that the new PBG cover is very efficient for improving the radiation directivity. The physical reasons for the improvement are also given.
基金Project (No. 2004CB719802) supported by the National Basic Research Program (973) of China
文摘A metamaterial was introduced into the cover of a patch antenna and its band structure was analyzed. The metama- terial cover with correct selection of the working frequency increases by 9.14 dB the patch antenna’s directivity. The mechanism of metamaterial cover is completely different from that of a photonic bandgap cover. The mechanism of the metamaterial cover, the number of the cover’s layers, and the distance between the layers, were analyzed in detail. The results showed that the metamaterial cover, which works like a lens, could effectively improve the patch antenna’s directivity. The physical reasons for the improvement are also given.
基金Project (No. Y105543) supported by the Natural Science Founda-tion of Zhejiang Province, China
文摘A new patch antenna system with a metamaterial cover is presented in this paper. The impedance, radiation pattern, and directivity of such an antenna are studied. A performance comparison between the conventional patch antenna and the new metamaterial patch antenna is given. The results show that the directivity of the metamaterial patch antenna is significantly im- proved. The effect of the metamaterial cover’s layer numbers on the radiation pattern of the patch antenna is also studied.
文摘Different feeding techniques of microstrip patch antennas with different spiral defected ground structures are presented in this paper. The investigated structures illustrate some merits in designing multi-electromagnetic band-gap structures by adjusting the capacitance and changing the inductance through varying the width and length of spiral defected ground structure. Then by applying the three different spirals shapes (one, two and four arms) as the ground plane of microstrip patch antenna with different feeding techniques to create multi or ultra wide-band, improve the antenna gain and reduce the antenna size, it is found that the four arms spiral defected ground structure of microstrip patch antenna with offset feed gives good performance, electrical size reduction to about 75% as compared to the original patch size and ultra-wide bandwidth extends from 2 GHz up to 12 GHz with ?8 dB impedance bandwidth.
文摘The finite element modeling of three dimensional structures is important for researchers especially in the field of antennas and other domains of electromagnetic waves. This paper presents a finite element calculations and numerical analysis for the microstrip patch antennas. In this paper, two different designs have been modelled and analyzed and both designs are based on the rectangular patches. The feeding point of one design is inside the patch while the other design contains feeding point outside the patch is T shaped. The computational analysis showed some interesting results for radiation pattern and far field domain. For these designs, the characteristic impedance taken is 50 Ω and the operating frequency domain is 1.4 to 1.7 GHz. The microstrip patch antennas are encapsulated in the inert spherical atmosphere of 20 mm thickness containing air inside it.
文摘This paper presents the design of a fully packaged 60 GHz wideband patch antenna incorporating an air cavity and a fused silica superstrate. Circular polarization (CP) is realized by introducing a diagonal slot at the center of the square patch. By optimizing the patch and the slot dimensions, a high efficiency (>90%) microstrip fed CP antenna with an impedance bandwidth of 24% and a 6 dB axial ratio bandwidth of 21.5% is designed. A coplanar waveguide (CPW) to microstrip transition with λ/4-open-ended stubs are then designed to match the antenna to the CPW packaging interface. The experimental results of the final packaged antenna agree reasonably with the simulation results, demonstrating an impedance bandwidth of more than 26% and a 6 dB axial ratio bandwidth of 22.7%.
文摘A single layer triangular patch antenna fed by an L-shaped probe was investigated numerically by using FDTD (Finite Difference Time Domain) method. It achieves >40% impedance bandwidth (VSWR<2) and stable radiation pattern across the passband. The triangular patch antenna with two orientations of L-shaped probe has almost the same characteristics, such as impedance bandwidth and radiation pattern. The bandwidth vs feeding position was also investigated, the broadband characteristic can be observed when the feeding position is only in a small segment along the centerline.
基金Project(61105067)supported by the National Natural Science Foundation of China
文摘A new multi-species particle swarm optimization with a two-level hierarchical topology and the orthogonal learning strategy(OMSPSO) is proposed, which enhances the global search ability of particles and increases their convergence rates. The numerical results on 10 benchmark functions demonstrated the effectiveness of our proposed algorithm. Then, the proposed algorithm is presented to design a butterfly-shaped microstrip patch antenna. Combined with the HFSS solver, a butterfly-shaped patch antenna with a bandwidth of about 40.1% is designed by using the proposed OMSPSO. The return loss of the butterfly-shaped antenna is greater than 10 d B between 4.15 and 6.36 GHz. The antenna can serve simultaneously for the high-speed wireless computer networks(5.15–5.35 GHz) and the RFID systems(5.8 GHz).
基金supported bythe IT R&D programof MKE/ⅡTA:Study of technologies for improving the RF spectrum characteristics by using the meta-electromagnetic structurec(2009-F-033-01)
基金supported by the IT R&D program of MKE/IITA.2009-F-033-02,Study of technologies for improving the RF spectrum characteristics by using the meta-electromagnetic structure.
文摘A patch antenna and our proposed metamaterial patch antenna are simulated and compared. A high gain patch antenna using a single layer metamaterial superstrate with a near to zero refractive index(n)is proposed.The simulation results provide that the gain of the proposed antenna is increased by about 7dB. Consequently,the high gain antenna can be easily obtained by using our metamaterial superstrate.
基金Project (No. 2006AA04Z368) supported by the Hi-Tech Researchand Development Program (863) of China
文摘Antenna is very crucial to radiotelemetry capsules which can measure the physiological parameters of the gastroin- testinal (GI) tract. The objective of this paper is to design a novel spiral slots microstrip patch antenna for the radiotelemetry capsules communicating with external recorder at 915 MHz located in ISM (Industry, Science, and Medical) bands. The microstrip patch antenna is designed and evaluated using the finite-difference time-domain (FDTD) method. Return loss characteristics and the effect of the human body on resonant frequency are analyzed, and the performances of radiation patterns at different positions of the human alimentary tract are also estimated. Finally, specific absorption rate (SAR) computations are performed, and the peak 1-g and 10-g SAR values are calculated. According to the peak SAR values, the maximum delivered power for the designed antenna was found so that the SAR values of the antenna satisfy the ANSI (American National Standards Institute) limitations.