Three-Antenna Characterization Techniques Employing Spherical Near-Field Scanning With Higher-Order Probe Correction

The three-antenna technique is typically used in the context of absolute-gain measurements where no gain standard is required. When implemented in a spherical near-field test range, the conventional approach is to use near-field-to-far-field transformation algorithms with first-order probe correction, which severely limits the choice of antennas that can occupy the probe position. Two new techniques, which are based on higher-order probe correction, are presented. These enable the full characterization of up to three higher-order antennas. The first technique, where only two of the antennas need to occupy the probe position, is useful for the accurate characterization of at least the antenna that is not employed as a probe. The second technique, where all antennas, in turn, occupy the probe position, allows for the accurate characterization of each antenna.