<title>Wideband subarray sizing requirements for digital-beamforming arrays employing multiple digitally resteered beams</title>

Abstract

Adopting a digital beamforming (DBF) architecture for phased array radars offers the advantage that multiple spatial channels are available the digital computer thereby enabling the use of a wide range of advanced array signal processing algorithms. Many of these algorithms rely on the ability to digitally re-steer beams in the vicinity of the nominal receive sum beam. At the current level of technology, DBF can only be practically implemented at a subarray level for large arrays operating at high frequencies. As a consequence, analog phase shifters at the element level may be set to point the beam in one location while digital re-steering is being used to move the beam to another location. In this paper, the performance impacts of digital re-steering are evaluated in terms of dispersion loss, and a simple correction factor is derived to compensate for a beam pointing error that results from digitally re-steering a beam to a location different from the location used to set the element level phase shifters.

Requirements for true time delay imaging systems with photonic components

“…Both solutions are bulky and add weight. In receive, the more futuristic solution is heading towards digital beamforming with a widehand receiver on each subarray [3]. An attractive solution to the problem of true time delay in transmit is a photonic based beamformer, typically using dispersive devices (Fig.…”