A Cassegrain antenna design for terahertz focal plane imaging system

A Cassegrain antenna for terahertz focal plane imaging system is proposed in the article. The antenna is designed according to the actual requirements of the THz detector feeds. The antenna is simulated by using CST. The simulation results show good performance with the gain of 56 dBi and the 3 dB bandwidth of 0.26° at 340 GHz. When the feed offset reached maximum at $\delta=15\text{mm}$ , the antenna gain is 54.3dBi. And when the feed is defocused by 1mm laterally, the beam pointing deflection is about 0.12°.