Calibration of standard gain horn antennas in the frequency range from 220 to 325 GHz

The actual gains of standard gain horn antennas with an operating frequency range from 220 to 325 GHz were calibrated experimentally by the three-antenna method. To determine the actual gain precisely, the required distance between the transmitting and receiving antennas was clarified by evaluating the propagation loss in terms of the distance between the antennas. In addition, to ensure the validity of the experimental results, the actual gain was also calculated using an electromagnetic simulator.