Since leaky-wave antennas(LWAs)have the advantages of high directivity,low loss and structural simplicity,LWAs are very suitable for designing millimeter-wave(mmW)antennas.The purpose of this paper is to review the la...Since leaky-wave antennas(LWAs)have the advantages of high directivity,low loss and structural simplicity,LWAs are very suitable for designing millimeter-wave(mmW)antennas.The purpose of this paper is to review the latest research progress of LWAs for 5G/B5G mobile communication systems.Firstly,the conventional classification and design methods of LWAs are introduced and the effects of the phase constant and attenuation constant on the radiation characteristics are discussed.Then two types of new LWAs for 5G/B5G mobile communication systems including broadband fixed-beam LWAs and frequencyfixed beam-scanning LWAs are summarized.Finally,the challenges and future research directions of LWAs for 5G/B5G mobile communication systems are presented.展开更多
Dynamically controlling terahertz(THz)wavefronts in a designable fashion is highly desired in practice.However,available methods working at microwave frequencies do not work well in the THz regime due to lacking suita...Dynamically controlling terahertz(THz)wavefronts in a designable fashion is highly desired in practice.However,available methods working at microwave frequencies do not work well in the THz regime due to lacking suitable tunable elements with submicrometer sizes.Here,instead of locally controlling individual meta-atoms in a THz metasurface,we show that rotating different layers(each exhibiting a particular phase profile)in a cascaded metadevice at different speeds can dynamically change the effective Jonesmatrix property of the whole device,thus enabling extraordinary manipulations on the wavefront and polarization characteristics of a THz beam impinging on the device.After illustrating our strategy based on model calculations,we experimentally demonstrate two proof-of-concept metadevices,each consisting of two carefully designed all-silicon transmissive metasurfaces exhibiting different phase profiles.Rotating two metasurfaces inside the fabricated devices at different speeds,we experimentally demonstrate that the first metadevice can efficiently redirect a normally incident THz beam to scan over a wide solid-angle range,while the second one can dynamically manipulate both the wavefront and polarization of a THz beam.Our results pave the way to achieving dynamic control of THz beams,which is useful in many applications,such as THz radar,and bio-and chemical sensing and imaging.展开更多
基金the National Natural Science Foundation of China(NSFC)under Grants 62071306 and 61801299in part by the Mobil⁃ity Program for Taiwan Young Scientists under Grant RW2019TW001and in part by Shenzhen Science and Technology Program under Grants GJHZ20180418190529516 and JSGG20180507183215520.
文摘Since leaky-wave antennas(LWAs)have the advantages of high directivity,low loss and structural simplicity,LWAs are very suitable for designing millimeter-wave(mmW)antennas.The purpose of this paper is to review the latest research progress of LWAs for 5G/B5G mobile communication systems.Firstly,the conventional classification and design methods of LWAs are introduced and the effects of the phase constant and attenuation constant on the radiation characteristics are discussed.Then two types of new LWAs for 5G/B5G mobile communication systems including broadband fixed-beam LWAs and frequencyfixed beam-scanning LWAs are summarized.Finally,the challenges and future research directions of LWAs for 5G/B5G mobile communication systems are presented.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.11704240,11734007,and 91850101)the National Key Research and Development Program of China(Grant Nos.2017YFA0303504 and 2017YFA0700201)+1 种基金the Shanghai Science and Technology Committee(Grant Nos.18QA1401800,20JC1414601,and 20JC1414602)the Shanghai East Scholar Plan,Fudan University-CIOMP Joint Fund(No.FC2018-006)。
文摘Dynamically controlling terahertz(THz)wavefronts in a designable fashion is highly desired in practice.However,available methods working at microwave frequencies do not work well in the THz regime due to lacking suitable tunable elements with submicrometer sizes.Here,instead of locally controlling individual meta-atoms in a THz metasurface,we show that rotating different layers(each exhibiting a particular phase profile)in a cascaded metadevice at different speeds can dynamically change the effective Jonesmatrix property of the whole device,thus enabling extraordinary manipulations on the wavefront and polarization characteristics of a THz beam impinging on the device.After illustrating our strategy based on model calculations,we experimentally demonstrate two proof-of-concept metadevices,each consisting of two carefully designed all-silicon transmissive metasurfaces exhibiting different phase profiles.Rotating two metasurfaces inside the fabricated devices at different speeds,we experimentally demonstrate that the first metadevice can efficiently redirect a normally incident THz beam to scan over a wide solid-angle range,while the second one can dynamically manipulate both the wavefront and polarization of a THz beam.Our results pave the way to achieving dynamic control of THz beams,which is useful in many applications,such as THz radar,and bio-and chemical sensing and imaging.
