Hybrid Beam Former for Distributed-Aperture Electronically Steered Arrays

This letter presents a concept for a hybrid beam former that is composed of two stages: an RF stage with limited scanning steps and a digital stage that is capable of steering multiple beams of different channels in all required directions. The two-stage beam former uses fewer A/D converters than its all-digital counterpart and lower losses than the all-RF beam former. Examples are given for multifaceted or conformal apertures. Although the examples are limited to one-dimensional (1-D) scanning, the concept is valid for two-dimensional (2-D) scanning as well.