Gain measurement of a patch antenna using S-parameters with different distances

Shortened far-field gain measurement method had been proposed for one of gain measurement methods that does not require replacement of antennas and measurement of distance between antennas. In this study, the shortened far-field gain measurement method was investigated by the simulation of a patch antenna in 2.5 GHz band. Because this antenna is narrow bandwidth and measured distance is relatively near, the influence of reflection and standing wave caused by multiple reflections is not negligible. It was found that even in multiple reflection environment, the reflection can be compensated and the error of the gain is less than 0.1 dBi.