Equivalence between Kim Method and Omi Method in Single-Cut Near-to-Far-Field Transformations for Antenna Near-Field Measurements

Two promising methods (Kim method and Omi method) in the single-cut near-to-far-field transformations are shown to be equivalent. The derivations and forms of the two methods are quite different: the Kim method is derived from a cylindrical near-field transmission equation with some approximations and the Omi method is derived from an approximation of the free-space Green function and using the plane wave expansions in the 2-D fast multipole method. Whereas the appearance of the equations of both methods are quite different, both methods are proved to be equivalent mathematically.

I. Introduction

In recent antenna measurements, near-field measurement techniques [1] are essential to determine 3-D antenna patterns or cut-plane patterns for various kinds of antennas. However the measurements require often a few hours because the sampling points to be measured are on the 2-D surfaces with some required intervals. Then it is very important to reduce the sampling points in order to reduce the measurement time.