Phaseless spherical near-field antenna measurements: Concept, algorithm and simulation

A novel phaseless near-field far-field transformation algorithm for spherical antenna measurements has been presented. The algorithm expands the radiated AUT field distribution in spherical harmonics and the missing phase information is retrieved in an iterative manner from an additional amplitude measurement on a second sphere. The spherical phase retrieval algorithm has been verified using simulated near-field data of a patch antenna and showed good performance. The avoidance of phase measurements, especially at high frequencies, allows antenna near-field measurements with reduced constraints in terms of instrumentation and probe positioning accuracy.