Antenna Gain Evaluation Based on Weighting Near-Field Measurements

Antenna gain is generally extracted from near-field measurements when the size of the measuring site (anechoic chamber or open area test site) does not meet the far-field constraints that include both distance and probe size limitation. Near-field measurements are usually performed by scanning the field on a closed surface around the antenna with a small size probe. In this paper, we show that the distance averaging method that we have previously proposed for gain evaluation in a multipath environment can also be employed for measurements in the near-field zone. We introduce an alternative technique to extract the gain by applying weighting functions on the near-field data when the size of the probe cannot be neglected compared to the wavelength. We validated our method by comparing the results to the gain measured at distances in the far-field region.