Generalized Broadband Beamforming using a

We propose a new broadband beamformer design technique which produces an optimal receiver beampattern 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, non-uniform and asynchronous time sampling, and dynamic arrays where sensors can move throughout space. It can also be applied to any beampattern type, including frequencyinvariant and spot pattern design. A simple extension to the technique is presented for oversampled arrays which allows highresolution beamforming whilst carefully controlling input energy and error sensitivity