Near-Field Focused Antenna Array Based on Three-Dimensional Coaxial Waveguide Feed Network with Separate Amplitude and Phase Control

Abstract

This paper presents a near-field focused antenna array based on a three-dimensional coaxial waveguide feed network to realize flexible array excitations with separate phase and amplitude control. The feed network is comprised of a tapered coaxial waveguide power divider with a three-stage 36-way coaxial probe array, and 36 coaxial cables to connect the power divider and the antenna array. The amplitude and phase of the array excitations can be separately controlled by adjusting the lengths of the coaxial probes and the coaxial cables. A prototype antenna array operating at 5.8 GHz is designed to verify its potential to adjust the amplitude and phase distributions simultaneously. The antenna demonstrates three different focusing scenarios in which the measured −3 dB spot diameter/focal distance is 50/165 mm, 110/415 mm, and 114/415 mm, respectively.