为缩短太赫兹系统成像时间,该文提出将频率扫描天线应用于太赫兹成像系统中,并设计了一种基于波导缝隙阵列的太赫兹频率扫描天线.该文采用泰勒综合法降低副瓣电平,通过软件仿真结合功率传输法设计最优的缝隙分布.太赫兹波导缝隙阵列天线具有加工简单、成本低的优势,通过太赫兹准光测试系统对天线性能进行测试,实测天线扫描角度可达40°,增益约为15 dB,副瓣电平抑制优于–20 dB.测试结果表明太赫兹波导缝隙天线具有扫描角度大和副瓣低的优良特性,在太赫兹成像和目标探测等领域有巨大的应用价值.%This research proposes a novel terahertz frequency scanning antenna based on slotted waveguide arrays, and the antenna consisted of 31 elements in a linear array. Usually, the mechanical steering scheme is employed to realize two-dimensional terahertz imaging for most of the systems that inherently have a low frame rate limitation. As an attractive scheme to obtain high frame rate, electrical beam steering by frequency scanning antennas is the preferable approach. Previous scanning waveguide arrays operating on terahertz band cannot suppress sidelobe levels effectively. Thus, to fulfill the requirement of high radiation efficiency, low waveguide loss, and low sidelobe levels, arranging the slots to conform to Taylor distribution was considered. The distributions effectively become frequency-dependent for the beam-steering concept. Compared with the uniform slot distribution, a Taylor distribution ensures broadband radiation patterns with low sidelobe levels. Furthermore, the offset of the slots has been optimized through a power transmission method in combination with full wave simulation. The frequency-controlled beam steering concept and the sidelobe suppression effect were verified by the quasi-optical measurements in the 0.2 THz band. The fabricated slot-array antenna has large angle scanning ability and a low sidelobe property. In addition, the measured scanning range is larger than 50° with a moderate gain of 15 dB over the frequency band 165~215 GHz. The sidelobe levels are remarkably inhibited over 20 dB normalized to the mainlobe level, and the measured radiation patterns and sidelobe suppression effects agree well with HFSS full-wave simulation. The proposed beam-steering antenna has potential applications for THz imaging with a high frame rate.
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