This study presents, for the first time, a novel design of ultra‐wideband (UWB), circularly polarized and highly directive log‐spiral THz photoconductive antenna. The proposed antenna is simulated in High Frequency Structure Simulator using gold as the antenna electrode material which is backed by a quartz substrate (ε_r = 3.78, tan δ = 0.0001) and hemispherical silicon‐based lens with a diameter of 140 μm. A comprehensive detailed parametric study of the antenna design parameters is performed in the frequency range of 1 to 6 THz for the optimal design of the developed antenna structure. The optimal antenna structure with integrated lens has UWB characteristics with −10 dB impedance bandwidth of 5 THz and 3 dB axial ratio bandwidth of around 4 THz. The observed directivity and half‐power beam width of the presented design varies in the range 5 to 12 dBi and 34° to 62°, respectively, for the frequency range of 1 to 4 THz. The wideband, high directivity as well as high‐efficiency (>50%) characteristics of the proposed design make it a favorable choice for the THz sensing and imaging applications.

中文翻译：

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宽带高定向对数螺旋太赫兹光电导天线的全波数值分析

这项研究首次提出了超宽带（UWB），圆偏振和高定向对数螺旋THz光电导天线的新颖设计。拟议的天线在高频结构仿真器中进行了仿真，使用金作为天线电极材料，并以石英衬底作为支撑（_εr= 3.78，tanδ= 0.0001）和直径为140μm的半球形硅基透镜。在1至6 THz的频率范围内，对天线设计参数进行了全面详细的参数研究，以优化已开发天线结构。具有集成透镜的最佳天线结构具有UWB特性，其具有5 THz的-10 dB阻抗带宽和4 THz左右的3 dB轴向比率带宽。对于1至4 THz的频率范围，本设计的观测方向性和半功率波束宽度分别在5至12 dBi和34°至62°的范围内变化。拟议设计的宽带，高方向性以及高效率（> 50％）特性使其成为太赫兹感测和成像应用的理想选择。