Near-field gain measurements: Single-probe distance averaging in a multipath site versus multi-probe field scanning inside an anechoic chamber

The size of a site for antenna gain measurements is usually correlated with the lower limit of the far-field range; otherwise, near-field to far-field transforms should be performed on data resulting from a field scanning with one or more electrically small probes. The site is typically a reflection free one (e.g., anechoic chamber) or a multi-path site with low correlation between different propagation paths (e.g., reverberation chamber). In this paper, we show that antenna gain can also be assessed in a regular, multi-path environment, mostly in the near-field zone, and with only one probe of a size comparable to the wavelength. We used a data processing technique that we have previously proposed, based on calculating an average transfer function. We compared gain results extracted with our method to results provided by a multiprobe, professional system using an anechoic chamber and near-field to far-field transforms.