This study demonstrates a simple 2-bit phased array operating at 27 GHz that supports one-dimensional beam scanning with left-handed circular polarization(LHCP).The antenna is constructed using a compact four-layer pr...This study demonstrates a simple 2-bit phased array operating at 27 GHz that supports one-dimensional beam scanning with left-handed circular polarization(LHCP).The antenna is constructed using a compact four-layer printed circuit board(PCB)structure,consisting of a 90°phase shifter layer with microstrip structures,a ground(GND)layer,a direct current(DC)control layer,and a circularly polarized annular radiation patch layer with 1-bit phase shifting.Based on the proposed unit structure,a 1×8 array with half-wavelength inter-element spacing was designed and validated.Experimental results show that the array achieves a peak gain of 10.23 dBi and is capable of beam scanning within±50°.展开更多
A phased array feed(PAF)is a type of receiving array that places phased array antennas on the focal plane of a radio telescope to expand its field of view and improve observation efficiency.Owing to the mutual couplin...A phased array feed(PAF)is a type of receiving array that places phased array antennas on the focal plane of a radio telescope to expand its field of view and improve observation efficiency.Owing to the mutual coupling effect between elements caused by a tightly arranged feed array,which changes the performance of a PAF,this paper presents a 7×7 rectangular feed array model for a 25 m reflector telescope.By adjusting the element spacings,the performance of a PAF with different spacings is comprehensively analyzed with respect to the mutual coupling effect via performance statistics and comparison.This research aims to provide a reference for the preliminary design of a related PAF.展开更多
In this paper,we have proposed a novel structure of Ka-band based phased array antenna with calibration function.In the design of Kaband antenna,the active phased array system is adopted and the antenna would work in ...In this paper,we have proposed a novel structure of Ka-band based phased array antenna with calibration function.In the design of Kaband antenna,the active phased array system is adopted and the antenna would work in the dual polarization separation mode.We have given out the schematic diagram for the proposed Ka-band antenna,where the Kaband antenna is in the form of waveguide slot array antenna,with 96 units in azimuth and 1 unit in distance.Each group of units is driven by a singlechannel Transmitter/Receiver(T/R)component,and the whole array contains 192 T/R components in total.The size of the T/R component is 55mm(length)×50mm(width)×5.8mm(height),3 Sub-micro Sub-Miniature Push-on(SSMP)blind sockets and a 21-core low-frequency socket are designed on the two sides of the T/R component.In order to meet the technical specifications of phased array antenna,the Ka-band transceiver component is designed based on Low Temperatrue Co-fired Ceramic(LTCC)technology to achieve miniaturization and lightweight.In our approach,the feed network includes two parts:transceiver network and calibration network.The transceiver network consists of 241:8 time-delay power dividers,12 two-way power dividers and 2 six-way time-delay power dividers.The power supply required by theKaband antenna unit is provided to each active component by the power module after Ka band wavelet control distribution.Simulation and measurement results are given in the form of standing wave and scanning capability.展开更多
In this paper,an antenna array composed of circular array and orthogonal linear array is proposed by using the design of long and short baseline“orthogonal linear array”and the circular array ambiguity resolution de...In this paper,an antenna array composed of circular array and orthogonal linear array is proposed by using the design of long and short baseline“orthogonal linear array”and the circular array ambiguity resolution design of multi-group baseline clustering.The effectiveness of the antenna array in this paper is verified by sufficient simulation and experiment.After the system deviation correction work,it is found that in the L/S/C/X frequency bands,the ambiguity resolution probability is high,and the phase difference system error between each channel is basically the same.The angle measurement error is less than 0.5°,and the positioning error is less than 2.5 km.Notably,as the center frequency increases,calibration consistency improves,and the calibration frequency points become applicable over a wider frequency range.At a center frequency of 11.5 GHz,the calibration frequency point bandwidth extends to 1200 MHz.This combined antenna array deployment holds significant promise for a wide range of applications in contemporary wireless communication systems.展开更多
The influence of the distorted plane of the active phased array antenna on the electromagnetic performance is of great significance to the research on and development of the high-performance antennas. On the bent and ...The influence of the distorted plane of the active phased array antenna on the electromagnetic performance is of great significance to the research on and development of the high-performance antennas. On the bent and bowl-shape distortion, the model is established of the relationship between the electromagnetic performance and the position error of the radiated elements. The method is presented of analyzing the far-field pattern of the distorted rectangular active phased array antenna. The analysis results of a planar phased array antenna with different distortions grades prove the validity of the model. Therefore, by the method, the antenna designers may set the reasonable requirement on the structural tolerance in manufacturing antenna.展开更多
The investigation of the effect of electrical and mechanical errors on the performance of a large active phased array antenna is studied. These errors can decrease the antenna performance, for instance, the gain reduc...The investigation of the effect of electrical and mechanical errors on the performance of a large active phased array antenna is studied. These errors can decrease the antenna performance, for instance, the gain reduction, side lobe level enhancement, and incorrect beam direction. In order to improve the performance of the antenna in the presence of these errors, phase error correction of large phased array antennas using the genetic algorithm(GA) is implemented. By using the phase compensation method, the antenna overall radiation pattern is recovered close to the ideal radiation pattern without error. By applying the simulation data to a 32×40 array of elements with a square grid at the frequency of S-band and measurement of the radiation pattern, the effectiveness of the proposed method is verified.展开更多
To gain the tradeoff between lower sidelobe and higher power amplifiers efficiency,a transmitting beam shaping scheme with limited amplitude weight values for satellite active phased array antenna is presented. The sc...To gain the tradeoff between lower sidelobe and higher power amplifiers efficiency,a transmitting beam shaping scheme with limited amplitude weight values for satellite active phased array antenna is presented. The scheme is implemented by a dual coding genetic algorithm(GA). Phase and amplitude of array weight vectors for beam shaping are encoded by real coding and finite length binary coding,respectively,which,maintaining accuracy of results,reduces the amplitude dynamic range and improves the efficiency of power amplifiers. The presented algorithm,compared with complex-coded GA,increases the convergence rate due to the search space's decrease. In order to overcome the prematurity and obtain better global optimization or quasi-global optimization,a new dual coding GA based on "species diversity retention" strategy and adaptive crossover and mutation probability are presented.展开更多
A novel phased array antenna consisting of 256 elements is presented and experimentally verified for 5G millimeter-wave wireless communications.The antenna integrated with a wave control circuit can perform real-time ...A novel phased array antenna consisting of 256 elements is presented and experimentally verified for 5G millimeter-wave wireless communications.The antenna integrated with a wave control circuit can perform real-time beam scanning by reconfiguring the phase of an antenna unit.The unit,designed at 28 GHz using a simple patch structure with one PIN diode,can be electronically controlled to generate 1 bit phase quantization.A prototype of the antenna is fabricated and measured to demonstrate the feasibility of this approach.The measurement results indicate that the antenna achieves high gain and fast beam-steering,with the scan beams within±60°range and the maximum gain up to 21.7 dBi.Furthermore,it is also tested for wireless video transmission.In ZTE Shanghai,the antenna was used for the 5G New Radio(NR)test.The error vector magnitude(EVM)is less than 3%and the adjacent channel leakage ratio(ACLR)less than−35 dBc,which can meet 5G system requirements.Compared with the conventional phased array antenna,the proposed phased array has the advantages of low power consumption,low cost and conformal geometry.Due to these characteristics,the antenna is promising for wide applications in 5G millimeter-wave communication systems.展开更多
In this work, we performed first-principles electromagnetic-kinetic simulations to study a phased antenna array and its interaction with deuterium plasmas within the lower hybrid range of frequency. We first gave wave...In this work, we performed first-principles electromagnetic-kinetic simulations to study a phased antenna array and its interaction with deuterium plasmas within the lower hybrid range of frequency. We first gave wave accessibility and resonance results, which agree well with theoretical prediction. In addition, we further investigated the antenna power spectrum with different antenna phases in the presence of the plasma and compared it with that in a vacuum,which directly indicates wave coupling and plasma absorption. Furthermore, for the case with zero phasing difference, our simulation results show that, albeit the launch is away from the accessibility region, tunneling effect and mode conversion occurred, which enhanced coupling and absorption. Moreover, consistent interactions between the injected wave and the plasma concerning various antenna phase differences are shown. We presented the inchoate response of the plasma in terms of the launching directions. Our results could be favorable for the engineering design of wave heating experiments with a tunable phased antenna array in linear devices, such as simple magnetic mirrors or tandem mirrors.展开更多
Now a day’s accidents are very common due to increased population of vehicle. In order to ensure safety measures in the vehicle this paper has proposed some methodologies regarding careful driving by automatically sc...Now a day’s accidents are very common due to increased population of vehicle. In order to ensure safety measures in the vehicle this paper has proposed some methodologies regarding careful driving by automatically scanning and analyzing the blind spot area of an intelligent mobile vehicle. A vehicular antenna with minimum perturbation is proposed to be fitted on the vehicle and collect information of the concern area which would ensure visibility of the operator i.e. masked or integrated within the car body. This paper has dealt with the design of Tchebyscheff polynomial based prototype planar microstrip phased array antenna and also redesigned the same when implemented in the body of the car being considered as an electromagnetically large element. Both the design has been experimentally verified with the measurement. The simulated and the measured results in both the cases are found to be in good agreement. More than 11 dB gain was observed at perfectly 30° angles from its broad side direction as desired for blind spot detection with minimum amount of electromagnetic interference inside the car.展开更多
The problem for calculating near fields of EM radiation systems by using the finitedifference time domain(FD-TD)method are discussed and the annular phased array of dipoleantennas has been simulated numerically by use...The problem for calculating near fields of EM radiation systems by using the finitedifference time domain(FD-TD)method are discussed and the annular phased array of dipoleantennas has been simulated numerically by use of the FD-TD method.For a test run thenear field and current distribution of the single dipole antenna are calculated.The near fieldsof the annular phased array of dipole antennas in central region filled with deionized water arecomputed and the interaction of near fields with an anatomically-based inhomogeneous model ofhuman torso is considered as well.展开更多
An aperture design technique using multi-step amplitude quantization for two-dimensional solid-state active phased arrays to achieve low sidelobe is described. It can be applied to antennas with arbitrary complex aper...An aperture design technique using multi-step amplitude quantization for two-dimensional solid-state active phased arrays to achieve low sidelobe is described. It can be applied to antennas with arbitrary complex aperture. Also, the gain drop and sidelobe degradation due to random amplitude and phase errors and element (or T/R module) failures are investigated.展开更多
In order to reduce the volume and weight of phase array antenna in RF frequency, an integrated technology of multi-channel transceiver circuit and power division network in microwave is proposed for the tile type TR m...In order to reduce the volume and weight of phase array antenna in RF frequency, an integrated technology of multi-channel transceiver circuit and power division network in microwave is proposed for the tile type TR module. The component is integrated in a same dielectric substrate, the mounting interface of chips and power division network are on the same layer. Finally, a 8 × 8 array has been manufactured and tested to validate its function. The results show the integrated technology has good performance. It is very good to satisfy the miniaturization and lightweight of the T/R module in the active phased array antenna.展开更多
The impedance of a solid state active phased array antenna varing with frequency and beam scanning scanning angle be matched with the solid state active matching network (SSAMN). In order to adjust and measure the rad...The impedance of a solid state active phased array antenna varing with frequency and beam scanning scanning angle be matched with the solid state active matching network (SSAMN). In order to adjust and measure the radar conveniently and Securely, it is necessary for the impedance of the simulator of the phased array antennas to be optimized.Having selected the PIN dilde controlling circuits and the circuit parameters optimized,the simulator circuit is determined through numerical computation The experiment is given in support of the simulation.展开更多
In high performance aerospace systems where weight and aerodynamics are of major concern, fiber reinforced composite laminates can be tailored to achieve desirable mechanical properties and accommodate low-profile mic...In high performance aerospace systems where weight and aerodynamics are of major concern, fiber reinforced composite laminates can be tailored to achieve desirable mechanical properties and accommodate low-profile microstrip antenna. This work aims at the analysis of microstrip antenna array embedded in composite laminated substrates. The size of a single antenna is first calculated by spectral domain analysis to model the effects of the substrate’s electromagnetic property and the orientation of the laminate layers. The antenna array as well as the feed network, composed of microstrip transmission lines, quarter wave-length impedance transformers, and T-junction power dividers, is then tuned to accommodate the effects of the coupling between the antenna elements and the feed network loss. The performance of the 1 × 2, 1 × 4, and 1 × 8 linear array and 2 × 2 and 2 × 4 planar array are shown to have better directivity when embedded in composite laminated substrate compared with those when attached on isotropic substrate. Both 1 × 2 and 1 × 4 arrays at 2.4 GHz are validated experimentally to achieve better coverage.展开更多
Antennas are an indispensable element in wireless networks. For long-distance wireless communication, antenna gains need to be very strong (highly directive) because the signal from the antenna loses a lot of str...Antennas are an indispensable element in wireless networks. For long-distance wireless communication, antenna gains need to be very strong (highly directive) because the signal from the antenna loses a lot of strength as it travels over long distances. This is true in the military with missile, radar, and satellite systems, etc. Antenna arrays are commonly employed to focus electromagnetic waves in a certain direction that cannot be achieved perfectly with a single-element antenna. The goal of this study is to design a rectangular microstrip high-gain 2 × 1 array antenna using ADS Momentum. This microstrip patch array design makes use of the RT-DUROID 5880 as a substrate with a dielectric constant of 2.2, substrate height of 1.588 mm, and tangent loss of 0.001. To achieve efficient gain and return loss characteristics for the proposed array antenna, RT-Duroid is a good choice of dielectric material. The designed array antenna is made up of two rectangular patches, which have a resonance frequency of 3.3 GHz. These rectangular patches are excited by microstrip feed lines with 13 mm lengths and 4.8 mm widths. The impedance of the patches is perfectly matched by these transmission lines, which helps to get better antenna characteristics. At a resonance frequency of 3.3 GHz, the suggested antenna array has a directivity of 10.50 dB and a maximum gain of 9.90 dB in the S-band. The S parameters, 3D radiation pattern, directivity, gain, and efficiency of the constructed array antenna are all available in ADS Momentum.展开更多
A compact wideband microstrip array antenna with a squint beam is introduced without the matched load. Its measured beam is at 10° offset to the broadside with a measured gain of 12 dB at 10 GHz. The measured imp...A compact wideband microstrip array antenna with a squint beam is introduced without the matched load. Its measured beam is at 10° offset to the broadside with a measured gain of 12 dB at 10 GHz. The measured impedance bandwidth (voltage standing wave ratio (VSWR)≤2) is over 16%, which agrees well with the simulated one. It is a low-cost wideband design with compact simple structure, suited for military and commercial application.展开更多
In this article we propose a miniaturized dual-band electronically steerable parasitic array radiator (ESPAR) antenna. The antenna can generate up to two steerable beams. The beam-steering range of the proposed antenn...In this article we propose a miniaturized dual-band electronically steerable parasitic array radiator (ESPAR) antenna. The antenna can generate up to two steerable beams. The beam-steering range of the proposed antenna is 360˚ in the azimuth plane. The antenna’s eual-band coverage includes the frequency ranges from 2.3 GHz to 2.53 GHz and from 2.9 GHz to 3.7 GHz. The antenna consists of six folded parasitic monopole elements surrounding an active conical element. The folded monopole element design offers three times lower antenna height than that of the conventional ESPAR antennas. The active element has conical shape and it is larger in length than the parasitic monopole elements, this enables the dual-band operation. Thus, the proposed design is not only smaller than the conventional ESPAR antennas but it also achieves dual-band operation. Despite its compact design, the antenna has a peak gain of 6.3 dBi, which is equivalent to the gain of conventional ESPAR antennas. These characteristics make the antenna a good candidate for next generation communication systems.展开更多
A mutual coupling suppression method is proposed for microstrip antenna array by cutting four small semi-circle annular apertures on the metal plate. The structure of antenna array is composed of 2 × 2 four eleme...A mutual coupling suppression method is proposed for microstrip antenna array by cutting four small semi-circle annular apertures on the metal plate. The structure of antenna array is composed of 2 × 2 four elements. The antenna consists of double layer dielectric, and it realizes circular polarization characteristics by cutting rectangular slot on circular patch in the direction of 45°, by using aperture coupling feeding and reverse feeding principle. There is 90* phase difference between adjacent antenna elements. Thus, it cuts off the coupling current field between the elements, suppresses the surface wave and reduces the mutual coupling by cutting four semi-circle annular apertures symmetrically on the metal plate. The simulation results show that after cutting four semi-circle annular apertures, the antenna array coupling coefficients decrease significantly, and the side and back lobe levels are suppressed effectively with the gain of antenna improved. So the proposed method is effective to suppress microstrip antenna array mutual coupling.展开更多
With regard to the inferior techniques and low accuracy of phase center calibration of an antenna array, this paper proposes a new calibration method considering the actual antenna pointing by introducing a precise en...With regard to the inferior techniques and low accuracy of phase center calibration of an antenna array, this paper proposes a new calibration method considering the actual antenna pointing by introducing a precise engineering surveying technique to measure the real state of antennas. First, an industrial photogrammetric system is utilized to obtain the coordinates of points on antenna panels in different postures, and the actual pointing of the mechanical axis is obtained via least-squares fitting. Then, based on this, the coordinates of antenna rotation center are obtained by seeking the intersection of mechanical axes via using the matrix method. Finally, the mechanical axis in arbitrary postures is estimated based on the inverse-angle weighting interpolation method, and the reliable phase center is obtained by moving a fixed length from the projective center along the mechanical axis. An uplink antenna array including three ? 3 m antennas is taken as experimental object, and all photogrammetric coordinate systems are unified by the engineering control network, with each antenna phase center precisely calibrated via the proposed method. The results of electrical signal synthesis indicate that this method can effectively overcome the influence of gravity deformation and mechanical installation error, and enhance the synthetic signal magnitude of the uplink antenna array.展开更多
基金supported in part by the National Natural Science Foundation of China under Grant No.62171103in part by the National Natural Science Foundation of China“111”Project under Grant No.BP0719011.
文摘This study demonstrates a simple 2-bit phased array operating at 27 GHz that supports one-dimensional beam scanning with left-handed circular polarization(LHCP).The antenna is constructed using a compact four-layer printed circuit board(PCB)structure,consisting of a 90°phase shifter layer with microstrip structures,a ground(GND)layer,a direct current(DC)control layer,and a circularly polarized annular radiation patch layer with 1-bit phase shifting.Based on the proposed unit structure,a 1×8 array with half-wavelength inter-element spacing was designed and validated.Experimental results show that the array achieves a peak gain of 10.23 dBi and is capable of beam scanning within±50°.
基金This work was supported by the Chinese Academy of Sciences"Light of West China"Program(2020-XBQNXZ-018)the National Natural Science Foundation of China(11973078)the Natural Science Foundation of Xinjiang Uygur Autonomous Region(2022D01A358)。
文摘A phased array feed(PAF)is a type of receiving array that places phased array antennas on the focal plane of a radio telescope to expand its field of view and improve observation efficiency.Owing to the mutual coupling effect between elements caused by a tightly arranged feed array,which changes the performance of a PAF,this paper presents a 7×7 rectangular feed array model for a 25 m reflector telescope.By adjusting the element spacings,the performance of a PAF with different spacings is comprehensively analyzed with respect to the mutual coupling effect via performance statistics and comparison.This research aims to provide a reference for the preliminary design of a related PAF.
文摘In this paper,we have proposed a novel structure of Ka-band based phased array antenna with calibration function.In the design of Kaband antenna,the active phased array system is adopted and the antenna would work in the dual polarization separation mode.We have given out the schematic diagram for the proposed Ka-band antenna,where the Kaband antenna is in the form of waveguide slot array antenna,with 96 units in azimuth and 1 unit in distance.Each group of units is driven by a singlechannel Transmitter/Receiver(T/R)component,and the whole array contains 192 T/R components in total.The size of the T/R component is 55mm(length)×50mm(width)×5.8mm(height),3 Sub-micro Sub-Miniature Push-on(SSMP)blind sockets and a 21-core low-frequency socket are designed on the two sides of the T/R component.In order to meet the technical specifications of phased array antenna,the Ka-band transceiver component is designed based on Low Temperatrue Co-fired Ceramic(LTCC)technology to achieve miniaturization and lightweight.In our approach,the feed network includes two parts:transceiver network and calibration network.The transceiver network consists of 241:8 time-delay power dividers,12 two-way power dividers and 2 six-way time-delay power dividers.The power supply required by theKaband antenna unit is provided to each active component by the power module after Ka band wavelet control distribution.Simulation and measurement results are given in the form of standing wave and scanning capability.
文摘In this paper,an antenna array composed of circular array and orthogonal linear array is proposed by using the design of long and short baseline“orthogonal linear array”and the circular array ambiguity resolution design of multi-group baseline clustering.The effectiveness of the antenna array in this paper is verified by sufficient simulation and experiment.After the system deviation correction work,it is found that in the L/S/C/X frequency bands,the ambiguity resolution probability is high,and the phase difference system error between each channel is basically the same.The angle measurement error is less than 0.5°,and the positioning error is less than 2.5 km.Notably,as the center frequency increases,calibration consistency improves,and the calibration frequency points become applicable over a wider frequency range.At a center frequency of 11.5 GHz,the calibration frequency point bandwidth extends to 1200 MHz.This combined antenna array deployment holds significant promise for a wide range of applications in contemporary wireless communication systems.
基金supported partly by the National Natural Science Foundation of China(50805111)the Natural Science Basic Research Plan in Shaanxi Province of China(SJ08E_203.)
文摘The influence of the distorted plane of the active phased array antenna on the electromagnetic performance is of great significance to the research on and development of the high-performance antennas. On the bent and bowl-shape distortion, the model is established of the relationship between the electromagnetic performance and the position error of the radiated elements. The method is presented of analyzing the far-field pattern of the distorted rectangular active phased array antenna. The analysis results of a planar phased array antenna with different distortions grades prove the validity of the model. Therefore, by the method, the antenna designers may set the reasonable requirement on the structural tolerance in manufacturing antenna.
文摘The investigation of the effect of electrical and mechanical errors on the performance of a large active phased array antenna is studied. These errors can decrease the antenna performance, for instance, the gain reduction, side lobe level enhancement, and incorrect beam direction. In order to improve the performance of the antenna in the presence of these errors, phase error correction of large phased array antennas using the genetic algorithm(GA) is implemented. By using the phase compensation method, the antenna overall radiation pattern is recovered close to the ideal radiation pattern without error. By applying the simulation data to a 32×40 array of elements with a square grid at the frequency of S-band and measurement of the radiation pattern, the effectiveness of the proposed method is verified.
基金The project supported by National Natural Science Foundation of China (No. 60572095)Research Foundation for Doctors of ZZULI
文摘To gain the tradeoff between lower sidelobe and higher power amplifiers efficiency,a transmitting beam shaping scheme with limited amplitude weight values for satellite active phased array antenna is presented. The scheme is implemented by a dual coding genetic algorithm(GA). Phase and amplitude of array weight vectors for beam shaping are encoded by real coding and finite length binary coding,respectively,which,maintaining accuracy of results,reduces the amplitude dynamic range and improves the efficiency of power amplifiers. The presented algorithm,compared with complex-coded GA,increases the convergence rate due to the search space's decrease. In order to overcome the prematurity and obtain better global optimization or quasi-global optimization,a new dual coding GA based on "species diversity retention" strategy and adaptive crossover and mutation probability are presented.
文摘A novel phased array antenna consisting of 256 elements is presented and experimentally verified for 5G millimeter-wave wireless communications.The antenna integrated with a wave control circuit can perform real-time beam scanning by reconfiguring the phase of an antenna unit.The unit,designed at 28 GHz using a simple patch structure with one PIN diode,can be electronically controlled to generate 1 bit phase quantization.A prototype of the antenna is fabricated and measured to demonstrate the feasibility of this approach.The measurement results indicate that the antenna achieves high gain and fast beam-steering,with the scan beams within±60°range and the maximum gain up to 21.7 dBi.Furthermore,it is also tested for wireless video transmission.In ZTE Shanghai,the antenna was used for the 5G New Radio(NR)test.The error vector magnitude(EVM)is less than 3%and the adjacent channel leakage ratio(ACLR)less than−35 dBc,which can meet 5G system requirements.Compared with the conventional phased array antenna,the proposed phased array has the advantages of low power consumption,low cost and conformal geometry.Due to these characteristics,the antenna is promising for wide applications in 5G millimeter-wave communication systems.
基金supported by the National Key R&D Program of China (No. 2017YFE0301802)National Natural Science Foundation of China (Nos. 11905220, 11775219 and 12175226)。
文摘In this work, we performed first-principles electromagnetic-kinetic simulations to study a phased antenna array and its interaction with deuterium plasmas within the lower hybrid range of frequency. We first gave wave accessibility and resonance results, which agree well with theoretical prediction. In addition, we further investigated the antenna power spectrum with different antenna phases in the presence of the plasma and compared it with that in a vacuum,which directly indicates wave coupling and plasma absorption. Furthermore, for the case with zero phasing difference, our simulation results show that, albeit the launch is away from the accessibility region, tunneling effect and mode conversion occurred, which enhanced coupling and absorption. Moreover, consistent interactions between the injected wave and the plasma concerning various antenna phase differences are shown. We presented the inchoate response of the plasma in terms of the launching directions. Our results could be favorable for the engineering design of wave heating experiments with a tunable phased antenna array in linear devices, such as simple magnetic mirrors or tandem mirrors.
文摘Now a day’s accidents are very common due to increased population of vehicle. In order to ensure safety measures in the vehicle this paper has proposed some methodologies regarding careful driving by automatically scanning and analyzing the blind spot area of an intelligent mobile vehicle. A vehicular antenna with minimum perturbation is proposed to be fitted on the vehicle and collect information of the concern area which would ensure visibility of the operator i.e. masked or integrated within the car body. This paper has dealt with the design of Tchebyscheff polynomial based prototype planar microstrip phased array antenna and also redesigned the same when implemented in the body of the car being considered as an electromagnetically large element. Both the design has been experimentally verified with the measurement. The simulated and the measured results in both the cases are found to be in good agreement. More than 11 dB gain was observed at perfectly 30° angles from its broad side direction as desired for blind spot detection with minimum amount of electromagnetic interference inside the car.
文摘The problem for calculating near fields of EM radiation systems by using the finitedifference time domain(FD-TD)method are discussed and the annular phased array of dipoleantennas has been simulated numerically by use of the FD-TD method.For a test run thenear field and current distribution of the single dipole antenna are calculated.The near fieldsof the annular phased array of dipole antennas in central region filled with deionized water arecomputed and the interaction of near fields with an anatomically-based inhomogeneous model ofhuman torso is considered as well.
文摘An aperture design technique using multi-step amplitude quantization for two-dimensional solid-state active phased arrays to achieve low sidelobe is described. It can be applied to antennas with arbitrary complex aperture. Also, the gain drop and sidelobe degradation due to random amplitude and phase errors and element (or T/R module) failures are investigated.
文摘In order to reduce the volume and weight of phase array antenna in RF frequency, an integrated technology of multi-channel transceiver circuit and power division network in microwave is proposed for the tile type TR module. The component is integrated in a same dielectric substrate, the mounting interface of chips and power division network are on the same layer. Finally, a 8 × 8 array has been manufactured and tested to validate its function. The results show the integrated technology has good performance. It is very good to satisfy the miniaturization and lightweight of the T/R module in the active phased array antenna.
文摘The impedance of a solid state active phased array antenna varing with frequency and beam scanning scanning angle be matched with the solid state active matching network (SSAMN). In order to adjust and measure the radar conveniently and Securely, it is necessary for the impedance of the simulator of the phased array antennas to be optimized.Having selected the PIN dilde controlling circuits and the circuit parameters optimized,the simulator circuit is determined through numerical computation The experiment is given in support of the simulation.
文摘In high performance aerospace systems where weight and aerodynamics are of major concern, fiber reinforced composite laminates can be tailored to achieve desirable mechanical properties and accommodate low-profile microstrip antenna. This work aims at the analysis of microstrip antenna array embedded in composite laminated substrates. The size of a single antenna is first calculated by spectral domain analysis to model the effects of the substrate’s electromagnetic property and the orientation of the laminate layers. The antenna array as well as the feed network, composed of microstrip transmission lines, quarter wave-length impedance transformers, and T-junction power dividers, is then tuned to accommodate the effects of the coupling between the antenna elements and the feed network loss. The performance of the 1 × 2, 1 × 4, and 1 × 8 linear array and 2 × 2 and 2 × 4 planar array are shown to have better directivity when embedded in composite laminated substrate compared with those when attached on isotropic substrate. Both 1 × 2 and 1 × 4 arrays at 2.4 GHz are validated experimentally to achieve better coverage.
文摘Antennas are an indispensable element in wireless networks. For long-distance wireless communication, antenna gains need to be very strong (highly directive) because the signal from the antenna loses a lot of strength as it travels over long distances. This is true in the military with missile, radar, and satellite systems, etc. Antenna arrays are commonly employed to focus electromagnetic waves in a certain direction that cannot be achieved perfectly with a single-element antenna. The goal of this study is to design a rectangular microstrip high-gain 2 × 1 array antenna using ADS Momentum. This microstrip patch array design makes use of the RT-DUROID 5880 as a substrate with a dielectric constant of 2.2, substrate height of 1.588 mm, and tangent loss of 0.001. To achieve efficient gain and return loss characteristics for the proposed array antenna, RT-Duroid is a good choice of dielectric material. The designed array antenna is made up of two rectangular patches, which have a resonance frequency of 3.3 GHz. These rectangular patches are excited by microstrip feed lines with 13 mm lengths and 4.8 mm widths. The impedance of the patches is perfectly matched by these transmission lines, which helps to get better antenna characteristics. At a resonance frequency of 3.3 GHz, the suggested antenna array has a directivity of 10.50 dB and a maximum gain of 9.90 dB in the S-band. The S parameters, 3D radiation pattern, directivity, gain, and efficiency of the constructed array antenna are all available in ADS Momentum.
基金Project supported by the National Natural Science Foundation of China (Grant No.60871030)the Shanghai Leading Academic Discipline Project (Grant No.S30108)
文摘A compact wideband microstrip array antenna with a squint beam is introduced without the matched load. Its measured beam is at 10° offset to the broadside with a measured gain of 12 dB at 10 GHz. The measured impedance bandwidth (voltage standing wave ratio (VSWR)≤2) is over 16%, which agrees well with the simulated one. It is a low-cost wideband design with compact simple structure, suited for military and commercial application.
文摘In this article we propose a miniaturized dual-band electronically steerable parasitic array radiator (ESPAR) antenna. The antenna can generate up to two steerable beams. The beam-steering range of the proposed antenna is 360˚ in the azimuth plane. The antenna’s eual-band coverage includes the frequency ranges from 2.3 GHz to 2.53 GHz and from 2.9 GHz to 3.7 GHz. The antenna consists of six folded parasitic monopole elements surrounding an active conical element. The folded monopole element design offers three times lower antenna height than that of the conventional ESPAR antennas. The active element has conical shape and it is larger in length than the parasitic monopole elements, this enables the dual-band operation. Thus, the proposed design is not only smaller than the conventional ESPAR antennas but it also achieves dual-band operation. Despite its compact design, the antenna has a peak gain of 6.3 dBi, which is equivalent to the gain of conventional ESPAR antennas. These characteristics make the antenna a good candidate for next generation communication systems.
基金Qingdao Basic Research of Science and Technology Plan Projects(No.13-1-4-132-jch)
文摘A mutual coupling suppression method is proposed for microstrip antenna array by cutting four small semi-circle annular apertures on the metal plate. The structure of antenna array is composed of 2 × 2 four elements. The antenna consists of double layer dielectric, and it realizes circular polarization characteristics by cutting rectangular slot on circular patch in the direction of 45°, by using aperture coupling feeding and reverse feeding principle. There is 90* phase difference between adjacent antenna elements. Thus, it cuts off the coupling current field between the elements, suppresses the surface wave and reduces the mutual coupling by cutting four semi-circle annular apertures symmetrically on the metal plate. The simulation results show that after cutting four semi-circle annular apertures, the antenna array coupling coefficients decrease significantly, and the side and back lobe levels are suppressed effectively with the gain of antenna improved. So the proposed method is effective to suppress microstrip antenna array mutual coupling.
文摘With regard to the inferior techniques and low accuracy of phase center calibration of an antenna array, this paper proposes a new calibration method considering the actual antenna pointing by introducing a precise engineering surveying technique to measure the real state of antennas. First, an industrial photogrammetric system is utilized to obtain the coordinates of points on antenna panels in different postures, and the actual pointing of the mechanical axis is obtained via least-squares fitting. Then, based on this, the coordinates of antenna rotation center are obtained by seeking the intersection of mechanical axes via using the matrix method. Finally, the mechanical axis in arbitrary postures is estimated based on the inverse-angle weighting interpolation method, and the reliable phase center is obtained by moving a fixed length from the projective center along the mechanical axis. An uplink antenna array including three ? 3 m antennas is taken as experimental object, and all photogrammetric coordinate systems are unified by the engineering control network, with each antenna phase center precisely calibrated via the proposed method. The results of electrical signal synthesis indicate that this method can effectively overcome the influence of gravity deformation and mechanical installation error, and enhance the synthetic signal magnitude of the uplink antenna array.