Measurement of Far Field Radiation Pattern of 300GHz-band Cassegrain Antenna

Abstract

We measured far field pattern of a 300-GHz Cassegrain antenna. The far-field measurement of the high-gain antenna requires a transmission distance of several tens of meters or more, and the receiver system requires a dynamic range of more than 70 dB and high sensitivity. In this paper, we obtained a 300-GHz-band experimental radio station license in Japan and measured the far field pattern of a Cassegrain antenna with a gain of 45 dBi. We also measured the near field pattern of the antenna, and calculated the far field pattern from the near field pattern. The measured far field pattern and the calculated far field pattern from the near field pattern are in good agreement. The far field pattern agrees with the antenna pattern models described in Recommendation ITU-R that covers below 86 GHz.