Low-Cost and Accurate Broadband Beamforming Based on Narrowband Sub-Arrays

Simplified broadband beamformers can be constructed by sharing a single tapped-delay-line within a narrowband subarray. This paper discusses the use of fractional delay filters to a steering in the digital domain. For the narrowband subarrays, an optimisation approach is proposed to maintain an off-broadside look direction constraint as best as possible across a given frequency range. We demonstrate the advantage that this approach has for generating beamformers with accurate off-broadside look direction compared to a benchmark.