Frequency invariant beamforming without tapped delay-lines

Broadband beamforming, including frequency invariant beamforming, is often achieved by processing the received sensor signals through tapped delay-lines. Unlike most of the existing techniques, we propose a novel design method for three-dimensional frequency invariant beamformers without employing tapped delay-lines. The resultant beamformer, which can form a beam steerable along both the elevation angle and the azimuth angle, has a very simple implementation. A design example is provided to show the effectiveness of the proposed method.