Gain measurement of a horn antenna by shortened far-field technique with averaging

Shortened far-field gain measurement was performed for pyramidal horn antennas with gain of 18.7 dBi at 10 GHz in measurement. Identical two horn antennas were used as transmitter and receiver. A standing wave, which cause degradation of accuracy, was observed due to multiple reflections between the two horn antennas. Averaging technique was evaluated to enhance the accuracy of gain measurement, and improvement of the results was confirmed. The ripple of gain is reduced from 1.55 dB to 0.45 dB with averaging. The average of measured gain with averaging of S21 was 18.0 dBi and difference from the theory was 0.7 dBi.