Design and Implementation of a Wideband Antenna Subarray for Phased-Array Applications

A wideband antenna subarray with a hybrid feeding network is proposed for phased-array applications. The subarray is a multilayer structure, where the top four-layer printed circuit board (PCB) is for antennas, middle two-layer metallic waveguides are for interconnections, and bottom eight-layer PCB is for the transition between the feeding network and active circuits. The middle metallic waveguides can not only improve the isolation between the antenna and active circuits but also serve as the heat dispersion structure of the active circuits and a low-loss power distribution network. Two kinds of novel transitions with bandpass filtering function and a technique for broadening the impedance bandwidth of the antenna element are proposed. Besides, a subarray with the SIW feeding network is proposed focusing on the wideband characteristic. The experimental results of the subarray prototypes show that the impedance bandwidths of 26.7%, 19%, and 51% are achieved. An array with 16 subarrays is fabricated and the beam-scanning characteristic is measured for validating the phased-array applications of the subarray. A phased-array system can be designed with such subarrays followed with transceivers and phase shifters. Combined with a low-accuracy mechanical tracking system, it can be efficiently used for the dynamic intersatellite communications.