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  • Research Article
  • Open Access

Generalized Broadband Beamforming Using a Modal Subspace Decomposition

  • 1Email author,
  • 1 and
  • 1
EURASIP Journal on Advances in Signal Processing20062007:068291

  • Received: 29 September 2005
  • Accepted: 1 April 2006
  • Published:


We propose a new broadband beamformer design technique which produces an optimal receiver beam pattern for any set of field measurements in space and time. The modal subspace decomposition (MSD) technique is based on projecting a desired pattern into the subspace of patterns achievable by a particular set of space-time sampling positions. This projection is the optimal achievable pattern in the sense that it minimizes the mean-squared error (MSE) between the desired and actual patterns. The main advantage of the technique is versatility as it can be applied to both sparse and dense arrays, nonuniform and asynchronous time sampling, and dynamic arrays where sensors can move throughout space. It can also be applied to any beam pattern type, including frequency-invariant and spot pattern designs. A simple extension to the technique is presented for oversampled arrays, which allows high-resolution beamforming whilst carefully controlling input energy and error sensitivity.


  • Input Energy
  • Pattern Type
  • Pattern Design
  • Sampling Position
  • Simple Extension

Authors’ Affiliations

Department of Information Engineering, Research School of Information Sciences and Engineering, Canberra, ACT 0200, Australia


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© Michael I. Y. Williams et al. 2007

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.