太赫兹光电导天线广泛应用于宽带脉冲太赫兹波的检测, 是太赫兹光谱和成像系统中的重要器件。偶极子光电导天线由于其结构简单、制作容易成为使用最广泛的一类太赫兹光电导接收天线。衡量太赫兹光电导探测天线的一个重要指标是其响应带宽。针对偶极子天线的探测带宽, 分别对天线臂长为10、50、150 μm的偶极子天线及一种作为对比的178 μm的蝶形天线(Bowtie antenna)进行了实验及理论研究。结果显示其探测带宽随天线臂长增加而减小, 与微波天线理论一致。进一步的, 采用商用电磁场数值仿真软件进行建模仿真, 仿真结果与理论及实验结果具有很好的一致性, 证实数值仿真已在很大程度上模拟出实际天线的特性, 从而为优化结构参数制作大宽带和高灵敏度的太赫兹天线提供支持。同时, 对超半球硅衬底透镜对天线接收频谱的影响也进行了探讨。

Terahertz(THz) photoconductive antennas(PCAs) are widely used in the detection of broadband pulsed terahertz waves and are important components in THz spectroscopy and imaging systems. Due to its simple structure and ease of fabrication, the dipole photoconductive antenna is the mostly used antenna for THz receivers. The primary specification of THz antennas is the bandwidth. To study the detection bandwidth of PCAs, dipole antennas with the arm length of 10, 50 and 150 μm and a bowtie antenna with the arm length of 178 μm were studied theoretically and experimentally. The results showed that the detection bandwidth decreased with the increase of the antenna arm length, which is consistent with the microwave antenna theory. Further, a commercial electromagnetic field numerical software was used for simulation. The results were in good agreement with the theoretical and experimental results and the model could be able to predict the performance of actual THz PCAs. The simulation can be used to design broadband and high sensitive THz antennas by optimizing structural parameters. The use of a hyper-hemispherical silicon substrate lens on the back of the receivers was also studied.