Broadband beamforming using Laguerre filters

Space–time processing is a well-substantiated method for designing broadband beamformers. In the conventional Frost space–time beamformer, tapped delay line (TDL) filters are used in each branch of the array to create a wideband response for interference suppression. In this article a new space–time beamforming method is introduced in which Laguerre filters replace the traditional TDL filters in the Frost beamformer. The Laguerre filters are fundamentally IIR filters but with only one pole in their structure. Unlike other IIR-based space–time beamforming methods, the proposed method does not need an adaptive procedure for the pole adjustment and is inherently stable. Simulation results show superior performance of the proposed method compared to the Frost beamformer and comparable results against other IIR-based beamformers with much less computational complexity and guaranteed stability.

► We propose a new space–time broadband beamformer based on Laguerre filter design.
► The new method shows better performance compared to conventional methods.
► The proposed method is inherently stable and is computationally less demanding.
► The new method shows deep nulls and better frequency invariant property.