An improved method of reducing SWE order for phaseless spherical near-field antenna measurement

Abstract

This paper presents a method of reconstructing far-field characteristics by using phaseless spherical near-field measurement, which is used to solve insufficient phase information problem in the near-field measurement of the antenna under test. This method firstly samples the amplitude of two spherical surfaces with different radius in the near-field region, and then iteratively recovers the phase of a sampling spherical electric field based on the spherical wave expansion (SWE) method of spherical near-field measurement. Finally, the far-field data is calculated by combining the simulation near-field measurement amplitude and recovered phase. In this paper, we compare the far-field results of near-far field transform algorithm and phaseless spherical algorithm with different sampling intervals and analyze the error of phaseless spherical algorithm. Then, an improved method of reducing SWE order is proposed. The simulation results show that the far-field characteristics of the antenna can be calculated effectively by adjusting the SWE order.