The tuning-fork gravitational wave antenna is a resonant one used for detecting the low-frequency continuous gravitational waves from the pulsar. Now, a tuningfork antenna with collective mass used for detecting the g...The tuning-fork gravitational wave antenna is a resonant one used for detecting the low-frequency continuous gravitational waves from the pulsar. Now, a tuningfork antenna with collective mass used for detecting the gravitational wave from展开更多
With the development of multi-band wireless communication and the increasing data transmission rate,the circulator as an antenna interface must be able to work in multiple frequency bands and provides large bandwidth....With the development of multi-band wireless communication and the increasing data transmission rate,the circulator as an antenna interface must be able to work in multiple frequency bands and provides large bandwidth.It presents a high challenge to the design of circulators,especially the active quasi-circulators.In this survey,we review the representative active quasi-circulators and summarize three different techniques and the corresponding structures to show an incremental improvement of the isolation and bandwidth of the active quasi-circulators.In addition,we also compare the performance of several state-of-art active circulators,and analyze their advantages and disadvantages.Finally,we conclude the future trend of the active quasi-circulators.展开更多
A new dual-polarized staggered and stacked patches antenna with wide impedance band-width and high isolation is proposed.The antenna consists of two groups of radiation patches,in 7 layers,and uses the orthogonal adja...A new dual-polarized staggered and stacked patches antenna with wide impedance band-width and high isolation is proposed.The antenna consists of two groups of radiation patches,in 7 layers,and uses the orthogonal adjacent coupling structure on staggered layer to excite a pair of linear polarization modes.Thanks to the staggered feeder mode,it has increased the isolation performance be-tween ports and compressed the transverse size of the antenna.As a result of the combination of staggered stack-up between the patches and the stepped gradient shape of the main radiating patches,it has effectively expanded the impedance bandwidth of the antenna.The proposed antenna is simulated,fabricated and measured.The staggered feeding structure effectively reduces the cross-sectional area of the antenna,and greatly improves the isolation between feeding ports.The measurement results show that the impedance bandwidths for vertical and horizontal polarization modes are 40.2%(638-960 MHz)and 40.0%(645-968 MHz)respectively when the return loss is lower than-10 dB,and the isolation between feeding ports is better than-30 dB.Meanwhile,the antenna has a stable and symmetrical radiation pattern across the working band,therefore making it suitable to be used as antenna and antenna array element of mobile wireless communication base stations.展开更多
A cross-shaped photonic crystal waveguide formed by a square lattice Al_2O_3 rods array is numerically and experimentally investigated. The band gap of the TE mode for the photonic crystals and transmission characteri...A cross-shaped photonic crystal waveguide formed by a square lattice Al_2O_3 rods array is numerically and experimentally investigated. The band gap of the TE mode for the photonic crystals and transmission characteristics of waveguides are calculated by the plane wave expansion method and the finite element method.We perform the experiments in the microwave regime to validate the numerical results. The measured reflection and transmission characteristics of the photonic crystals show a large band gap between 8.62 and 11.554 GHz（relative bandwidth is 29.34%）. The electromagnetic waves are transmitted stably in the waveguides, and the transmission characteristics maintain a high level in the band gap.展开更多
文摘The tuning-fork gravitational wave antenna is a resonant one used for detecting the low-frequency continuous gravitational waves from the pulsar. Now, a tuningfork antenna with collective mass used for detecting the gravitational wave from
文摘With the development of multi-band wireless communication and the increasing data transmission rate,the circulator as an antenna interface must be able to work in multiple frequency bands and provides large bandwidth.It presents a high challenge to the design of circulators,especially the active quasi-circulators.In this survey,we review the representative active quasi-circulators and summarize three different techniques and the corresponding structures to show an incremental improvement of the isolation and bandwidth of the active quasi-circulators.In addition,we also compare the performance of several state-of-art active circulators,and analyze their advantages and disadvantages.Finally,we conclude the future trend of the active quasi-circulators.
基金Natural Science Founda-tion of China(Grant 61171051 and 61771063)Plan-ning projects of Hebei provincial department(Grant 15210410)Research Fund Project of North China Institute of Aerospace Engineering(Grant BKY-2021-13)。
文摘A new dual-polarized staggered and stacked patches antenna with wide impedance band-width and high isolation is proposed.The antenna consists of two groups of radiation patches,in 7 layers,and uses the orthogonal adjacent coupling structure on staggered layer to excite a pair of linear polarization modes.Thanks to the staggered feeder mode,it has increased the isolation performance be-tween ports and compressed the transverse size of the antenna.As a result of the combination of staggered stack-up between the patches and the stepped gradient shape of the main radiating patches,it has effectively expanded the impedance bandwidth of the antenna.The proposed antenna is simulated,fabricated and measured.The staggered feeding structure effectively reduces the cross-sectional area of the antenna,and greatly improves the isolation between feeding ports.The measurement results show that the impedance bandwidths for vertical and horizontal polarization modes are 40.2%(638-960 MHz)and 40.0%(645-968 MHz)respectively when the return loss is lower than-10 dB,and the isolation between feeding ports is better than-30 dB.Meanwhile,the antenna has a stable and symmetrical radiation pattern across the working band,therefore making it suitable to be used as antenna and antenna array element of mobile wireless communication base stations.
基金supported by the National Natural Science Foundation of China under Grant No.61171006
文摘A cross-shaped photonic crystal waveguide formed by a square lattice Al_2O_3 rods array is numerically and experimentally investigated. The band gap of the TE mode for the photonic crystals and transmission characteristics of waveguides are calculated by the plane wave expansion method and the finite element method.We perform the experiments in the microwave regime to validate the numerical results. The measured reflection and transmission characteristics of the photonic crystals show a large band gap between 8.62 and 11.554 GHz（relative bandwidth is 29.34%）. The electromagnetic waves are transmitted stably in the waveguides, and the transmission characteristics maintain a high level in the band gap.
