中文摘要：

针对连续太赫兹光电导天线辐射功率较低的缺点，利用有限积分方法对三种常用的光电导天线，包括偶极天线、蝶形天线和螺旋天线，进行数值模拟并分析比较其辐射阻抗特性．仿真结果表明，偶极天线的辐射阻抗与偶极长度、宽度、电极间隙以及传输线宽度有关，且在其谐振频率存在峰值阻抗，适用于特定频率的太赫兹波辐射．蝶形天线和螺旋天线在所研究的太赫兹波段具有近似稳定的辐射阻抗，广泛应用于宽带领域．对带有交叉电极的电极间隙进行计算，结果表明由交叉电极引入的附加电容降低了天线的高频阻抗．

英文摘要：

To overcome the disadvantage of low radiation power for photoconductive antenna, three types of antennas, including dipole, bow-tie and spiral antennas, are studied, where finite integration technology are used to compute their radiation impedances. The simulation results show that the impedance of dipole antenna is dependent on the dipole length, width, photoconductive gap and the width of transmission line, and has a peak value in resonant frequency, so the dipole antenna is suitable for applications working at specific terahertz frequency. The bow-tie and spiral antennas, known as broadband antennas, have approximately stable impedance over the terahertz frequency range under study. The simulation results also show that,the interdigitated fingers, which can be modelled as an additional capacitance, cause the antenna impedance to fall dramatically at high {requency.