A new multi-cell cellular configuration networks is provided for analysis of handover initiation probability, which is based on multi-beam base-station antenna splitting in the elevation-radiating plane. The sum of th...A new multi-cell cellular configuration networks is provided for analysis of handover initiation probability, which is based on multi-beam base-station antenna splitting in the elevation-radiating plane. The sum of the received signal power in the mobile station, including both desired and interference signal power, has been introduced into the handover initiation algorithm. Along with the idea, we present three models of handover initiation algorithm with the shadowing process of Gaussian distribution. The formulation of handover initiation probability of those algorithms is also analyzed. The validity of the presented models has been checked through the comparison with simulation results. The results present the performance characteristics of handover initiation vary with cluster number and base-station antenna elevation angle.展开更多
For spaceborne multi-beam antennas(MBAs), time division multiplexed switching(TDMS) based calibration receiver can reduce implementation costs effectively and is very suitable for large-scale applications. However, in...For spaceborne multi-beam antennas(MBAs), time division multiplexed switching(TDMS) based calibration receiver can reduce implementation costs effectively and is very suitable for large-scale applications. However, in practice, random phase noise imposed by noisy local oscillators can cause significant performance degradation in TDMS-based calibration systems. Characterization of phase noise effects is therefore crucial for practical applications. In this paper, we analyze the impact of phase noise on the calibration performance for a MBA system. Specifically, we derive the relationship between the probability of correct amplitude/phase estimation and various practical factors involving the signal-to-noise ratio(SNR), the standard deviation of phase noise, the given tolerance region, and the length of the spreading code. The results provide high efficiency for evaluating the calibration performance of the MBAs based on TDMS, especially for precisely anticipating the impact of phase noise. Finally, the accuracy of the derived results is assessed by simulations in different scenarios.展开更多
In this study,the design,analysis,manufacturing,and testing of a 3D-printed conformal microstrip array antenna for high-temperature environments is presented.3D printing technology is used to fabricate a curved cerami...In this study,the design,analysis,manufacturing,and testing of a 3D-printed conformal microstrip array antenna for high-temperature environments is presented.3D printing technology is used to fabricate a curved ceramic substrate,and laser sintering and microdroplet spraying processes are used to add the conductive metal on the curved substrate.The problems of gain loss,bandwidth reduction,and frequency shift caused by high temperatures are addressed by using a proper antenna design,with parasitic patches,slots,and metal resonant cavities.The antenna prototype is characterized by the curved substrates and the conductive metals for the power dividers,the patch,and the ground plane;its performance is examined up to a temperature of 600℃in a muffle furnace and compared with the results from the numerical analysis.The results show that the antenna can effectively function at 600℃and even higher temperatures.展开更多
In this paper,a dual-band graphene-based frequency selective surface(GFSS)is investigated and the operating mechanism of this GFSS is analyzed.By adjusting the bias voltage to control the graphene chemical po-tential ...In this paper,a dual-band graphene-based frequency selective surface(GFSS)is investigated and the operating mechanism of this GFSS is analyzed.By adjusting the bias voltage to control the graphene chemical po-tential between 0 eV and 0.5 eV,the GFSS can achieve four working states:dual-band passband,high-pass lowimpedance,low-pass high-impedance,and band-stop.Based on this GFSS,a hexagonal radome on a broadband omnidirectional monopole antenna is proposed,which can achieve independent 360°six-beam omnidirectional scanning at 1.08 THz and 1.58 THz dual bands.In addition,while increasing the directionality,the peak gains of the dual bands reach 7.44 dBi and 6.67 dBi,respectively.This work provides a simple method for realizing multi-band terahertz multi-beam reconfigurable antennas.展开更多
A multi-beam adaptive antenna is investigated by considering the adaptive beam forming performance for time-variant channels on the focus of mobile to base station or reverse link. This antenna is constructed by Fresn...A multi-beam adaptive antenna is investigated by considering the adaptive beam forming performance for time-variant channels on the focus of mobile to base station or reverse link. This antenna is constructed by Fresnel zone phase-correcting plane （FZP） focusing element and uniformly spaced feeds array. An estimator for the beamforming weight vector in the presence of angle spreads is derived using a code filtering approach. Owing to the time-varying nature of the channels, a recursive method for computing and tracking the above optimal weight vector solution that is easy to implement is applied. The effects of angle spread, maximum Doppler frequency, and forgetting factor are studied. Simulation results showed that this type of adaptive antenna is capable of performing adaptive beam forming for time-variant channels effectively.展开更多
Bi-function Compact graphene lens antenna in terahertz (THz) band has been investigated. The array function is switched between two status, reflectarray and/or transmitarray. The tunability of graphene conductivity in...Bi-function Compact graphene lens antenna in terahertz (THz) band has been investigated. The array function is switched between two status, reflectarray and/or transmitarray. The tunability of graphene conductivity introduces the bi-function characteristics of a single array structure in the THz band. The design depends on changing the graphene DC biasing voltage to transform the transmitting antenna to reflecting antenna. The compact structure of the antenna array saves the cost and the allocation area for the terahertz communication applications. A 13 × 13 reflectarray/ transmitarray antenna covering an area of 364 × 364 μm<sup>2</sup> is proposed. A dual-beams reflectarray/transmitarray antenna is achieved by rearranging the cell elements of the array successively. Finally, a single structure is used to work as reflectarray and transmitarray antenna at the same time by rearranging the applied voltages between the different pieces of the graphene sheet using chess board arrangement. The phases of the successive unit-cells are kept the same of their locations in the original full array. The radiation characteristics of the array are investigated using the CST Microwave Studio for the bi-function operation.展开更多
The active multi-beam antenna can be widely used in the 6G integrated satellite network project,the national satellite Internet project,and other major satellite projects.It determines the key performance indicators o...The active multi-beam antenna can be widely used in the 6G integrated satellite network project,the national satellite Internet project,and other major satellite projects.It determines the key performance indicators of the satellite such as the service coverage area and the communication capacity of all the beams in the forward link and the return link.The active multi-beam antenna is the core technology of satellite payload and has been developed rapidly in recent years.Based on the antenna performance requirements such as the number of giant-scale beams,super-large coverage area,high gain,and high carrier-to-interference ratio(C/I),this paper proposes a new active multi-beam antenna design method,which integrates the multi-objective coordination and multi-feed amplitude and phase weighted optimization algorithms.A balanced optimal solution that meets the performance requirements can be obtained by constraining each other with different objective functions.In the optimization process,the surrogate model of convolutional autoencoder based on artificial intelligence technology is proposed for multi-objective optimization solution,which efficiently completes the search of optimal beam excitation coefficients.This paper takes the demand for very-high-throughput communication satellites serving the Asia-Pacific region as an example and applies the design method to the multi-beam antenna design of the satellite.The simulation verification of the antenna is completed,achieving good performance of 976 beams.All results meet the performance requirements,supporting the implementation of 1 Tbps communication capacity for the entire satellite,and verifying the correctness of the design method.展开更多
This paper presents a design method to implement an antenna array characterized by ultra-wide beam coverage,low profile,and low Sidelobe Level(SLL)for the application of Unmanned Aerial Vehicle(UAV)air-to-ground commu...This paper presents a design method to implement an antenna array characterized by ultra-wide beam coverage,low profile,and low Sidelobe Level(SLL)for the application of Unmanned Aerial Vehicle(UAV)air-to-ground communication.The array consists of ten broadside-radiating,ultrawide-beamwidth elements that are cascaded by a central-symmetry series-fed network with tapered currents following Dolph-Chebyshev distribution to provide low SLL.First,an innovative design of end-fire Huygens source antenna that is compatible with metal ground is presented.A low-profile,half-mode Microstrip Patch Antenna(MPA)is utilized to serve as the magnetic dipole and a monopole is utilized to serves as the electric dipole,constructing the compact,end-fire,grounded Huygens source antenna.Then,two opposite-oriented end-fire Huygens source antennas are seamlessly integrated into a single antenna element in the form of monopole-loaded MPA to accomplish the ultrawide,broadside-radiating beam.Particular consideration has been applied into the design of series-fed network as well as antenna element to compensate the adverse coupling effects between elements on the radiation performance.Experiment indicates an ultrawide Half-Power Beamwidth(HPBW)of 161°and a low SLL of-25 dB with a high gain of 12 d Bi under a single-layer configuration.The concurrent ultrawide beamwidth and low SLL make it particularly attractive for applications of UAV air-to-ground communication.展开更多
The integrated optical true time delay phased array antenna system has the advantages of high bandwidth,small size,low loss and strong antiinterference capability,etc.The high integration of the optically controlled p...The integrated optical true time delay phased array antenna system has the advantages of high bandwidth,small size,low loss and strong antiinterference capability,etc.The high integration of the optically controlled phased array antenna system is a necessary trend for the future development of the phased array,and it is also a major focus and difficulty in the current research of integrated microwave photonics.This paper firstly introduces the basic principle and development history of optical true time delay phased array antenna system based on microwave photonics,and briefly introduces the main implementation methods and integration platform of optical true time delay.Then,the application and development prospect of optical true time delay technology in beam control of phased array antenna system are mainly presented.Finally,according to the current research progress,the possible research directions of integrated optically controlled phased array antenna systems in the future are proposed.展开更多
Considering the environmental sustainability,the ceramic substrate is preferred in conventional global navigation satellite system(GNSS)antennas.However,the high-density ceramic increases the antennas'mass,and ban...Considering the environmental sustainability,the ceramic substrate is preferred in conventional global navigation satellite system(GNSS)antennas.However,the high-density ceramic increases the antennas'mass,and bandwidth of the GNSS antenna is narrowed by the high permittivity of ceramic.To solve these issues,a compact,lightweight circularly polarized(CP),transmitting(Tx)and receiving(Rx)integrated antenna was proposed for the lightweight and wide-bandwidth GNSS communications antennas.A hollowing sandwich layer was used to balance the bandwidth and weight performance.By optimizing hollowed dimensions,a lightweight and wide bandwidth GNSS antenna could be achieved.Both Tx-Rx antennas were integrated into a printed circuit board(PCB),minimizing the satellite installation space.Simulations and measurements are conducted.The results show that the operating frequency band around 1.6 GHz(Tx)and around 1.5 GHz(Rx),with realized gains 3 dBi(Tx)and 2.5 dBi(Rx).The total mass of the proposed antenna is around 59 g within a compact space of 50 mm×50 mm×10 mm.The proposed CP GNSS antennas show excellent performance in size,mass,and bandwidth,which can be a potential solution for the micro-nano satellite-ground communications.展开更多
A millimeter-wave (mmW) broadband dual circularly polarized (dual-CP) antenna with high port isolation is proposed in this paper. The dual-CP performance is realized based on the symmetrical septum circular polarizer ...A millimeter-wave (mmW) broadband dual circularly polarized (dual-CP) antenna with high port isolation is proposed in this paper. The dual-CP performance is realized based on the symmetrical septum circular polarizer based on the gap waveguide (GWG) technology. Two sets of symmetrical septum circular polarizers are used for common aperture combination,achieving the broadband dual-CP characteristics. Taking advantage of GWG structure without good electrical contact, the antenna can also be fabricated and assembled easily in the mmW band. The principle analysis of the antenna is given, and the antenna is simulated and fabricated. The measured results show that the bandwidth for S11lower than-10.7 dB and the axial ratio (AR) lower than 2.90 dB in 75-110 GHz, with realative bandwidth of 38%. Over the frequency band, the gain is higher than 9.16 dBic, and the dual-CP port isolation is greater than32 dB. The proposed antenna with dual-CP and highly isolated in a wide bandwidth range has broad application prospects in the field of mmW communication.展开更多
This paper begins with an overview of base station antennas,focusing on their structure and basic technical parameters.It then investigates the technical characteristics of three types of antennas—panel,Luneburg lens...This paper begins with an overview of base station antennas,focusing on their structure and basic technical parameters.It then investigates the technical characteristics of three types of antennas—panel,Luneburg lens,and innovative integrated antennas—in the context of railway 5G-R base station specifications.The advantages and disadvantages of these antenna types are compared and analyzed,and recommendations for the selection of 5G-R base station antennas are provided.Based on the special application scenarios of railway 5G-R base stations,this paper proposes connection methods between antennas and RRUs,and conducts a comparative analysis of antenna interface types.Furthermore,recommendations are provided for configuring the antenna information management module to meet the intelligent operation and maintenance requirements of the 5G-R system.The findings can serve as a reference for the selection and operation of antennas at railway 5G-R base stations.展开更多
In this study,the potential application of shaped charge jets as transient antennas for electromagnetic signal transmission was explored and an electromagnetic pulse radiation system with a shaped charge jet as a tran...In this study,the potential application of shaped charge jets as transient antennas for electromagnetic signal transmission was explored and an electromagnetic pulse radiation system with a shaped charge jet as a transient antenna was proposed.During the research,crucial characteristics of the transient antenna formed by a shaped charge with a 30 mm diameter,such as resonant frequency,radiation pattern,and radiation efficiency,were evaluated.The typical shaped charge jet morphology was obtained based on the simulations,in which it could insight the dynamic behavior of the shaped charge jet selected.An equivalent model experiment was employed to test the radiation efficiency,and it showed that a shorting pin loading method could increase the relative bandwidth of the jet antenna to 32.8%,and the experimental results correlate with the theoretical predictions for half-wave dipole antennas reasonably well.Additionally,variations in the diameter of the shaped charge jet were found to affect the input impedance and impedance bandwidth,while the length of the jet influenced the resonant frequency of the antenna.This suggests that altering these parameters can achieve reconfigurability of the jet antenna.展开更多
A triple-band miniaturized end-fire antenna based on the odd modes of spoof surface plasmonic polariton(SSPP)waveguide resonator is proposed in this paper.To meet the ever increasing demand for more communication chan...A triple-band miniaturized end-fire antenna based on the odd modes of spoof surface plasmonic polariton(SSPP)waveguide resonator is proposed in this paper.To meet the ever increasing demand for more communication channels and less antenna sizes,multi-band antennas are currently under intensive investigation.By a novel feeding method,three odd modes are excited on an SSPP waveguide resonator,which performs as an end-fire antenna operating at three bands,7.15-7.26 GHz,11.6-12.2 GHz and 13.5-13.64 GHz.It exhibits reasonably high and stable maximum gains of 5.26 dBi,7.97 dBi and 10.1 dBi and maximum efficiencies of 64%,92%and 98%at the three bands,respectively.Moreover,in the second band,the main beam angle shows a frequency dependence with a total scanning angle of 19°.The miniaturized triple-band antenna has a great potential in wireless communication systems,satellite communication and radar systems.展开更多
Navigation satellites generally use satellite-ground and inter-satellite observation data for precise orbit determination.In orbit determination,the satellite position is often referenced to the satellite’s centroid,...Navigation satellites generally use satellite-ground and inter-satellite observation data for precise orbit determination.In orbit determination,the satellite position is often referenced to the satellite’s centroid,while the observational measurements are referenced to the satellite’s antenna phase center.The deviation between the satellite’s centroid and the antenna phase center forms the satellite antenna phase center error,which affects the precision of orbit determination.This paper takes a global navigation satellite system(GNSS)MEO satellite as an example and analyzes the actual situation of the satellite antenna phase center deviation and phase center variation based on the ground calibration data of the in-orbit satellite antenna phase center and the satellite’s in-orbit working status.The analysis shows that the antenna phase center variation caused by the satellite’s in-orbit operation is only at the centimeter level,which has a limited impact on orbit determination accuracy.The main source of precise orbit determination error is the satellite antenna phase center deviation,which can be corrected using ground calibration data.展开更多
Non-orthogonal multiple access(NOMA)is a promising technology for the next generation wireless communication networks.The benefits of this technology can be further enhanced through deployment in conjunction with mult...Non-orthogonal multiple access(NOMA)is a promising technology for the next generation wireless communication networks.The benefits of this technology can be further enhanced through deployment in conjunction with multiple-input multipleoutput(MIMO)systems.Antenna selection plays a critical role in MIMO–NOMA systems as it has the potential to significantly reduce the cost and complexity associated with radio frequency chains.This paper considers antenna selection for downlink MIMO–NOMA networks with multiple-antenna basestation(BS)and multiple-antenna user equipments(UEs).An iterative antenna selection scheme is developed for a two-user system,and to determine the initial power required for this selection scheme,a power estimation method is also proposed.The proposed algorithm is then extended to a general multiuser NOMA system.Numerical results demonstrate that the proposed antenna selection algorithm achieves near-optimal performance with much lower computational complexity in both two-user and multiuser scenarios.展开更多
A wideband low-profile aperture-coupled antenna based on a novel dual-mode-composite scheme is presented.The mode-composite scheme where the TM10 cavity mode and the TE121 dielec-tric resonator(DR)mode are combined of...A wideband low-profile aperture-coupled antenna based on a novel dual-mode-composite scheme is presented.The mode-composite scheme where the TM10 cavity mode and the TE121 dielec-tric resonator(DR)mode are combined offers an ap-proach to obtain a wide bandwidth accompanied by stable unidirectional radiation and high efficiency.The use of a lengthened coupling aperture that supports the one-wavelength resonance in the band of interest is an effective feed method of simultaneously excit-ing the two composite modes without compromising the increased complexity of the antenna geometry.An impedance bandwidth of 49%for|S_(11)|of less than-10 dB,a maximum gain of 10.8 dBi,and stable radiation patterns with low cross-polarization are realized ex-perimentally by a fabricated prototype.Considering the simplicity of the geometry,the wide bandwidth that can cover n77,n78,and n79 bands for the fifth generation(5G)mobile communications and the sat-isfying radiation performance,the proposed antenna would be a promising candidate for advanced wireless applications.展开更多
A thin compact broadband coplanarfed rectangular-ring monopole antenna parasiticallyloaded by three nested concentric rectangle rings and aπ-shaped stub is proposed suitable for modern communication needs.It has an o...A thin compact broadband coplanarfed rectangular-ring monopole antenna parasiticallyloaded by three nested concentric rectangle rings and aπ-shaped stub is proposed suitable for modern communication needs.It has an overall area of only 25 mm×6 mm(0.29λ_(0)×0.07λ_(0)at 3.5 GHz),which can be the base radiating element of the MIMO array,being easily integrated into any wireless device.Its measured(simulated)fractional bandwidth is 24.6%(31.6%)ranging from 3.25(3.09)to 4.16(4.25)GHz,being applicable to the 5G N48,N77,and N78 bands.Practical guidelines are also provided to make the proposed design operate on some other additional 5G bands(e.g.,N41 or N46)without compromising its overall size.As far as the radiation properties are concerned,the antenna with such small dimensions radiates nearly bidirectionally and omnidirectionally in the E-and H-plane,respectively,and has an average measured(simulated)peak realized gain of-0.1(1.8)dBi over the band of interest.The proposed antenna is wideband,physically small and relatively easy to manufacture,making it straightforward to integrate with the RF electronics in IoT sensors.展开更多
Antennae are significant chemosensory and mechanosensory organs for insects and need careful maintenance.Bees use a pair of comb-like tools located on the forelimbs to brush and remove contaminants from their antennae...Antennae are significant chemosensory and mechanosensory organs for insects and need careful maintenance.Bees use a pair of comb-like tools located on the forelimbs to brush and remove contaminants from their antennae.We filmed antenna grooming in three different bee species and observed that all bees raise their heads while grooming their antennae.We conducted a study to examine the effects of the distinctive grooming apparatus,as well as the antenna’s material and structural characteristics,on grooming behavior in both free-head and constrained-head scenarios.Head-raising increases the grooming speed by 300%compared to the situation where the head is constrained.It allows the bees to scrape the antennae 5 times per second.In addition,we proposed a mechanical model based on the morphological data to determine that raising the head increases the contact force by 50%.These findings will facilitate the development of innovative approaches for cleaning extended structures featuring bristly surfaces.展开更多
文摘A new multi-cell cellular configuration networks is provided for analysis of handover initiation probability, which is based on multi-beam base-station antenna splitting in the elevation-radiating plane. The sum of the received signal power in the mobile station, including both desired and interference signal power, has been introduced into the handover initiation algorithm. Along with the idea, we present three models of handover initiation algorithm with the shadowing process of Gaussian distribution. The formulation of handover initiation probability of those algorithms is also analyzed. The validity of the presented models has been checked through the comparison with simulation results. The results present the performance characteristics of handover initiation vary with cluster number and base-station antenna elevation angle.
基金supported by the NSFC(Joint Foundation of NSFC&Fundamental Research for General Purpose Technologies)under Grant U1636125
文摘For spaceborne multi-beam antennas(MBAs), time division multiplexed switching(TDMS) based calibration receiver can reduce implementation costs effectively and is very suitable for large-scale applications. However, in practice, random phase noise imposed by noisy local oscillators can cause significant performance degradation in TDMS-based calibration systems. Characterization of phase noise effects is therefore crucial for practical applications. In this paper, we analyze the impact of phase noise on the calibration performance for a MBA system. Specifically, we derive the relationship between the probability of correct amplitude/phase estimation and various practical factors involving the signal-to-noise ratio(SNR), the standard deviation of phase noise, the given tolerance region, and the length of the spreading code. The results provide high efficiency for evaluating the calibration performance of the MBAs based on TDMS, especially for precisely anticipating the impact of phase noise. Finally, the accuracy of the derived results is assessed by simulations in different scenarios.
基金National Natural Science Foundation of China(No.U2241205)the Natural Science Basic Research Program of Shaanxi(Nos.2022JC-33,2023-GHZD-35,and 2024JC-ZDXM-25)+1 种基金the Fundamental Research Funds for the Central Universitiesthe National 111 Project to provide fund for conducting experiments。
文摘In this study,the design,analysis,manufacturing,and testing of a 3D-printed conformal microstrip array antenna for high-temperature environments is presented.3D printing technology is used to fabricate a curved ceramic substrate,and laser sintering and microdroplet spraying processes are used to add the conductive metal on the curved substrate.The problems of gain loss,bandwidth reduction,and frequency shift caused by high temperatures are addressed by using a proper antenna design,with parasitic patches,slots,and metal resonant cavities.The antenna prototype is characterized by the curved substrates and the conductive metals for the power dividers,the patch,and the ground plane;its performance is examined up to a temperature of 600℃in a muffle furnace and compared with the results from the numerical analysis.The results show that the antenna can effectively function at 600℃and even higher temperatures.
基金Supported by the Natural Science Foundation of Tibet Autonomous Region(XZ202401ZR0025)the National Natural Science Founda-tion of China(62164011,62301081)the Natural Science Foundation of Shaanxi Province(2022JQ-589)。
文摘In this paper,a dual-band graphene-based frequency selective surface(GFSS)is investigated and the operating mechanism of this GFSS is analyzed.By adjusting the bias voltage to control the graphene chemical po-tential between 0 eV and 0.5 eV,the GFSS can achieve four working states:dual-band passband,high-pass lowimpedance,low-pass high-impedance,and band-stop.Based on this GFSS,a hexagonal radome on a broadband omnidirectional monopole antenna is proposed,which can achieve independent 360°six-beam omnidirectional scanning at 1.08 THz and 1.58 THz dual bands.In addition,while increasing the directionality,the peak gains of the dual bands reach 7.44 dBi and 6.67 dBi,respectively.This work provides a simple method for realizing multi-band terahertz multi-beam reconfigurable antennas.
基金the Natural Science Foundation of Chongqing Municipal (CSTC2006BB2360)
文摘A multi-beam adaptive antenna is investigated by considering the adaptive beam forming performance for time-variant channels on the focus of mobile to base station or reverse link. This antenna is constructed by Fresnel zone phase-correcting plane （FZP） focusing element and uniformly spaced feeds array. An estimator for the beamforming weight vector in the presence of angle spreads is derived using a code filtering approach. Owing to the time-varying nature of the channels, a recursive method for computing and tracking the above optimal weight vector solution that is easy to implement is applied. The effects of angle spread, maximum Doppler frequency, and forgetting factor are studied. Simulation results showed that this type of adaptive antenna is capable of performing adaptive beam forming for time-variant channels effectively.
文摘Bi-function Compact graphene lens antenna in terahertz (THz) band has been investigated. The array function is switched between two status, reflectarray and/or transmitarray. The tunability of graphene conductivity introduces the bi-function characteristics of a single array structure in the THz band. The design depends on changing the graphene DC biasing voltage to transform the transmitting antenna to reflecting antenna. The compact structure of the antenna array saves the cost and the allocation area for the terahertz communication applications. A 13 × 13 reflectarray/ transmitarray antenna covering an area of 364 × 364 μm<sup>2</sup> is proposed. A dual-beams reflectarray/transmitarray antenna is achieved by rearranging the cell elements of the array successively. Finally, a single structure is used to work as reflectarray and transmitarray antenna at the same time by rearranging the applied voltages between the different pieces of the graphene sheet using chess board arrangement. The phases of the successive unit-cells are kept the same of their locations in the original full array. The radiation characteristics of the array are investigated using the CST Microwave Studio for the bi-function operation.
基金supported by the Fund from the National Natural Science Foundation of China(Grant No.62271387)a pre-research project on Civil Aerospace Technologies(Grant No.D010203).
文摘The active multi-beam antenna can be widely used in the 6G integrated satellite network project,the national satellite Internet project,and other major satellite projects.It determines the key performance indicators of the satellite such as the service coverage area and the communication capacity of all the beams in the forward link and the return link.The active multi-beam antenna is the core technology of satellite payload and has been developed rapidly in recent years.Based on the antenna performance requirements such as the number of giant-scale beams,super-large coverage area,high gain,and high carrier-to-interference ratio(C/I),this paper proposes a new active multi-beam antenna design method,which integrates the multi-objective coordination and multi-feed amplitude and phase weighted optimization algorithms.A balanced optimal solution that meets the performance requirements can be obtained by constraining each other with different objective functions.In the optimization process,the surrogate model of convolutional autoencoder based on artificial intelligence technology is proposed for multi-objective optimization solution,which efficiently completes the search of optimal beam excitation coefficients.This paper takes the demand for very-high-throughput communication satellites serving the Asia-Pacific region as an example and applies the design method to the multi-beam antenna design of the satellite.The simulation verification of the antenna is completed,achieving good performance of 976 beams.All results meet the performance requirements,supporting the implementation of 1 Tbps communication capacity for the entire satellite,and verifying the correctness of the design method.
基金supported by the National Natural Science Foundation of China(No.62371080 and 62031006)the National Science Foundation of Chongqing,China(No.CSTB2022NSCQ-MSX0597)the Venture&Innovation Support Program for Chongqing Overseas Returnees,China(No.cx2022063)。
文摘This paper presents a design method to implement an antenna array characterized by ultra-wide beam coverage,low profile,and low Sidelobe Level(SLL)for the application of Unmanned Aerial Vehicle(UAV)air-to-ground communication.The array consists of ten broadside-radiating,ultrawide-beamwidth elements that are cascaded by a central-symmetry series-fed network with tapered currents following Dolph-Chebyshev distribution to provide low SLL.First,an innovative design of end-fire Huygens source antenna that is compatible with metal ground is presented.A low-profile,half-mode Microstrip Patch Antenna(MPA)is utilized to serve as the magnetic dipole and a monopole is utilized to serves as the electric dipole,constructing the compact,end-fire,grounded Huygens source antenna.Then,two opposite-oriented end-fire Huygens source antennas are seamlessly integrated into a single antenna element in the form of monopole-loaded MPA to accomplish the ultrawide,broadside-radiating beam.Particular consideration has been applied into the design of series-fed network as well as antenna element to compensate the adverse coupling effects between elements on the radiation performance.Experiment indicates an ultrawide Half-Power Beamwidth(HPBW)of 161°and a low SLL of-25 dB with a high gain of 12 d Bi under a single-layer configuration.The concurrent ultrawide beamwidth and low SLL make it particularly attractive for applications of UAV air-to-ground communication.
基金supported by Fund of State Key Laboratory of IPOC(BUPT)(No.IPOC2021ZT16),China.
文摘The integrated optical true time delay phased array antenna system has the advantages of high bandwidth,small size,low loss and strong antiinterference capability,etc.The high integration of the optically controlled phased array antenna system is a necessary trend for the future development of the phased array,and it is also a major focus and difficulty in the current research of integrated microwave photonics.This paper firstly introduces the basic principle and development history of optical true time delay phased array antenna system based on microwave photonics,and briefly introduces the main implementation methods and integration platform of optical true time delay.Then,the application and development prospect of optical true time delay technology in beam control of phased array antenna system are mainly presented.Finally,according to the current research progress,the possible research directions of integrated optically controlled phased array antenna systems in the future are proposed.
基金funded by Basic Research Program of Jiangsu under grant BK20252030。
文摘Considering the environmental sustainability,the ceramic substrate is preferred in conventional global navigation satellite system(GNSS)antennas.However,the high-density ceramic increases the antennas'mass,and bandwidth of the GNSS antenna is narrowed by the high permittivity of ceramic.To solve these issues,a compact,lightweight circularly polarized(CP),transmitting(Tx)and receiving(Rx)integrated antenna was proposed for the lightweight and wide-bandwidth GNSS communications antennas.A hollowing sandwich layer was used to balance the bandwidth and weight performance.By optimizing hollowed dimensions,a lightweight and wide bandwidth GNSS antenna could be achieved.Both Tx-Rx antennas were integrated into a printed circuit board(PCB),minimizing the satellite installation space.Simulations and measurements are conducted.The results show that the operating frequency band around 1.6 GHz(Tx)and around 1.5 GHz(Rx),with realized gains 3 dBi(Tx)and 2.5 dBi(Rx).The total mass of the proposed antenna is around 59 g within a compact space of 50 mm×50 mm×10 mm.The proposed CP GNSS antennas show excellent performance in size,mass,and bandwidth,which can be a potential solution for the micro-nano satellite-ground communications.
文摘A millimeter-wave (mmW) broadband dual circularly polarized (dual-CP) antenna with high port isolation is proposed in this paper. The dual-CP performance is realized based on the symmetrical septum circular polarizer based on the gap waveguide (GWG) technology. Two sets of symmetrical septum circular polarizers are used for common aperture combination,achieving the broadband dual-CP characteristics. Taking advantage of GWG structure without good electrical contact, the antenna can also be fabricated and assembled easily in the mmW band. The principle analysis of the antenna is given, and the antenna is simulated and fabricated. The measured results show that the bandwidth for S11lower than-10.7 dB and the axial ratio (AR) lower than 2.90 dB in 75-110 GHz, with realative bandwidth of 38%. Over the frequency band, the gain is higher than 9.16 dBic, and the dual-CP port isolation is greater than32 dB. The proposed antenna with dual-CP and highly isolated in a wide bandwidth range has broad application prospects in the field of mmW communication.
文摘This paper begins with an overview of base station antennas,focusing on their structure and basic technical parameters.It then investigates the technical characteristics of three types of antennas—panel,Luneburg lens,and innovative integrated antennas—in the context of railway 5G-R base station specifications.The advantages and disadvantages of these antenna types are compared and analyzed,and recommendations for the selection of 5G-R base station antennas are provided.Based on the special application scenarios of railway 5G-R base stations,this paper proposes connection methods between antennas and RRUs,and conducts a comparative analysis of antenna interface types.Furthermore,recommendations are provided for configuring the antenna information management module to meet the intelligent operation and maintenance requirements of the 5G-R system.The findings can serve as a reference for the selection and operation of antennas at railway 5G-R base stations.
基金supported by the"Fundamental Research Funds for the Central Universities"(Grant No.30924010801).
文摘In this study,the potential application of shaped charge jets as transient antennas for electromagnetic signal transmission was explored and an electromagnetic pulse radiation system with a shaped charge jet as a transient antenna was proposed.During the research,crucial characteristics of the transient antenna formed by a shaped charge with a 30 mm diameter,such as resonant frequency,radiation pattern,and radiation efficiency,were evaluated.The typical shaped charge jet morphology was obtained based on the simulations,in which it could insight the dynamic behavior of the shaped charge jet selected.An equivalent model experiment was employed to test the radiation efficiency,and it showed that a shorting pin loading method could increase the relative bandwidth of the jet antenna to 32.8%,and the experimental results correlate with the theoretical predictions for half-wave dipole antennas reasonably well.Additionally,variations in the diameter of the shaped charge jet were found to affect the input impedance and impedance bandwidth,while the length of the jet influenced the resonant frequency of the antenna.This suggests that altering these parameters can achieve reconfigurability of the jet antenna.
基金supported in part by the Natural Science Foundation of Tianjin(No.19JCYBJC16100)the Tianjin Innovation and Entrepreneurship Training Program(No.202210060027)。
文摘A triple-band miniaturized end-fire antenna based on the odd modes of spoof surface plasmonic polariton(SSPP)waveguide resonator is proposed in this paper.To meet the ever increasing demand for more communication channels and less antenna sizes,multi-band antennas are currently under intensive investigation.By a novel feeding method,three odd modes are excited on an SSPP waveguide resonator,which performs as an end-fire antenna operating at three bands,7.15-7.26 GHz,11.6-12.2 GHz and 13.5-13.64 GHz.It exhibits reasonably high and stable maximum gains of 5.26 dBi,7.97 dBi and 10.1 dBi and maximum efficiencies of 64%,92%and 98%at the three bands,respectively.Moreover,in the second band,the main beam angle shows a frequency dependence with a total scanning angle of 19°.The miniaturized triple-band antenna has a great potential in wireless communication systems,satellite communication and radar systems.
文摘Navigation satellites generally use satellite-ground and inter-satellite observation data for precise orbit determination.In orbit determination,the satellite position is often referenced to the satellite’s centroid,while the observational measurements are referenced to the satellite’s antenna phase center.The deviation between the satellite’s centroid and the antenna phase center forms the satellite antenna phase center error,which affects the precision of orbit determination.This paper takes a global navigation satellite system(GNSS)MEO satellite as an example and analyzes the actual situation of the satellite antenna phase center deviation and phase center variation based on the ground calibration data of the in-orbit satellite antenna phase center and the satellite’s in-orbit working status.The analysis shows that the antenna phase center variation caused by the satellite’s in-orbit operation is only at the centimeter level,which has a limited impact on orbit determination accuracy.The main source of precise orbit determination error is the satellite antenna phase center deviation,which can be corrected using ground calibration data.
文摘Non-orthogonal multiple access(NOMA)is a promising technology for the next generation wireless communication networks.The benefits of this technology can be further enhanced through deployment in conjunction with multiple-input multipleoutput(MIMO)systems.Antenna selection plays a critical role in MIMO–NOMA systems as it has the potential to significantly reduce the cost and complexity associated with radio frequency chains.This paper considers antenna selection for downlink MIMO–NOMA networks with multiple-antenna basestation(BS)and multiple-antenna user equipments(UEs).An iterative antenna selection scheme is developed for a two-user system,and to determine the initial power required for this selection scheme,a power estimation method is also proposed.The proposed algorithm is then extended to a general multiuser NOMA system.Numerical results demonstrate that the proposed antenna selection algorithm achieves near-optimal performance with much lower computational complexity in both two-user and multiuser scenarios.
基金supported in part by the Beijing Natural Science Foundation No.JQ22011the National Science Foundation of China for Distinguished Young Scholars under Grant No.62325102+1 种基金the National Natural Science Foundation of China under Grant No.62031004the Fundamental Research Funds for the Central Universities No.2023YJS160.
文摘A wideband low-profile aperture-coupled antenna based on a novel dual-mode-composite scheme is presented.The mode-composite scheme where the TM10 cavity mode and the TE121 dielec-tric resonator(DR)mode are combined offers an ap-proach to obtain a wide bandwidth accompanied by stable unidirectional radiation and high efficiency.The use of a lengthened coupling aperture that supports the one-wavelength resonance in the band of interest is an effective feed method of simultaneously excit-ing the two composite modes without compromising the increased complexity of the antenna geometry.An impedance bandwidth of 49%for|S_(11)|of less than-10 dB,a maximum gain of 10.8 dBi,and stable radiation patterns with low cross-polarization are realized ex-perimentally by a fabricated prototype.Considering the simplicity of the geometry,the wide bandwidth that can cover n77,n78,and n79 bands for the fifth generation(5G)mobile communications and the sat-isfying radiation performance,the proposed antenna would be a promising candidate for advanced wireless applications.
文摘A thin compact broadband coplanarfed rectangular-ring monopole antenna parasiticallyloaded by three nested concentric rectangle rings and aπ-shaped stub is proposed suitable for modern communication needs.It has an overall area of only 25 mm×6 mm(0.29λ_(0)×0.07λ_(0)at 3.5 GHz),which can be the base radiating element of the MIMO array,being easily integrated into any wireless device.Its measured(simulated)fractional bandwidth is 24.6%(31.6%)ranging from 3.25(3.09)to 4.16(4.25)GHz,being applicable to the 5G N48,N77,and N78 bands.Practical guidelines are also provided to make the proposed design operate on some other additional 5G bands(e.g.,N41 or N46)without compromising its overall size.As far as the radiation properties are concerned,the antenna with such small dimensions radiates nearly bidirectionally and omnidirectionally in the E-and H-plane,respectively,and has an average measured(simulated)peak realized gain of-0.1(1.8)dBi over the band of interest.The proposed antenna is wideband,physically small and relatively easy to manufacture,making it straightforward to integrate with the RF electronics in IoT sensors.
基金supported by the National Natural Science Foundation of China(grant No.T2422031 and No.51905556).
文摘Antennae are significant chemosensory and mechanosensory organs for insects and need careful maintenance.Bees use a pair of comb-like tools located on the forelimbs to brush and remove contaminants from their antennae.We filmed antenna grooming in three different bee species and observed that all bees raise their heads while grooming their antennae.We conducted a study to examine the effects of the distinctive grooming apparatus,as well as the antenna’s material and structural characteristics,on grooming behavior in both free-head and constrained-head scenarios.Head-raising increases the grooming speed by 300%compared to the situation where the head is constrained.It allows the bees to scrape the antennae 5 times per second.In addition,we proposed a mechanical model based on the morphological data to determine that raising the head increases the contact force by 50%.These findings will facilitate the development of innovative approaches for cleaning extended structures featuring bristly surfaces.
