Wide-Bandwidth Phased Arrays using Random Subarraying

Abstract

Beam steering with phased arrays requires the use of true-time-delay devices when communicating a wideband signal. In many applications, this requirement cannot be met, due to size and cost limitations, and the array is divided into subarrays: each element is implemented with a phase shifter (frequency independent phase-shifting device) and each subarray is fed through a single true time delay. The common implementation is with identical contiguous subarrays, which, due to periodicity, cause high sidelobes and grating lobes. We suggest to design divided arrays by trying random sizes of subarrays, with random locations of their centers, in order to avoid periodicity. We develop closed-form expressions for the average array factor, the average power pattern and its variance.