Hongjian Wang, Xingchao Dong, Min Yi, Fei Xue, Yang Liu, Guang Liu
Two high gain terahertz offset reflector antennas are proposed. The silicon carbide material and thermally stable carbon fiber-reinforced plastic are selected as reflectors for high specific stiffness and low thermal expansion coefficient which are helpful for space use. Dual polarization is achieved by introducing a wire-grid polarizer which can separate the two terahertz polarization waves provided by multimode horns fabricated in electroforming technology. Furthermore, three-coordinate test system and theodolites are employed to detect the surface error of dishes and alignment of antenna subsystem. The physical optics analysis based on the measured reflector surface data is introduced referring to the large aperture antenna patterns by virtue of its accuracy and high efficiency. The results of this novel method are compared to that of the near field test. Measurements show that the side lobe levels of the single polarization silicon based reflector are below -32dB while the gain is 55.3dB at 330GHz, and the dual polarization carbon fiber-reinforced plastic reflector antenna suppresses the side lobe levels to -28dB and -29dB in two principal planes while the gain is 57.2dB at the same frequency, respectively. The good performances of the proposed antennas indicate the potential for the application of space terahertz radiometer.