Nested Randomly-Spaced Thinned Arrays for Multibeam Operation

This paper presents a novel method of generating multiple simultaneous beams from a single aperture using nested randomly-spaced thinned arrays. The full array aperture is partitioned into non-overlapping thinned arrays, with each array having its own beam. Each of these thinned nested sub-arrays maintain the 3-dB beamwidth of the fully-populated aperture while also being able to scan to arbitrary angles without triggering large grating lobes. Multiple narrow beams with high pattern fidelity can thus be synthesized without an increase in the number of RF channels in the array. This method is demonstrated in this work with randomly thinned square arrays at 19.5 GHz. Measurements using a 1024-element receive phased array show excellent scan performance of multiple arrays up to 60° with low sidelobes and no grating lobes. This work has important applications in lowering the cost and complexity of multiplebeam communication and radar systems.

I. Introduction

Phased arrays are pervasive in modern communication, radar, and imaging systems due to their ability to electronically steer the radiated beam. For modern commercial systems, reducing cost and complexity without hindering performance is becoming increasingly important.