Planar Near-field Phaseless Measurement Techniques for Antenna Characterizations and Diagnostics

This thesis describes the recent developments in applying phaseless near-field measurement techniques for constructing the antennas radiation patterns. The advantages of operating at higher frequencies and cost effectiveness of these techniques have motivated a great deal of research over the past decade. A brief description of the present methods is accompanied by a detailed investigation of the Iterative Fourier technique (IFT) as a powerful phaseless algorithm for planar near-field measurements. The issues associated with the standard form of IFT are addressed. Issues such as the difficulties in dealing with important classes of antennas such as scanned beams, or specifically polarized antennas, or the impact of probe-positioning errors, the need for co-rotation of probe and the measured antenna, and many others are thoroughly investigated. In this thesis for the first time robust phaseless algorithms addressing all of these issues are developed. Using both simulation and measurements based on the UCLA bi-polar near-field facility, it is demonstrated that the developed algorithms can address the needs of antenna measurements community.