Constant Beamwidth Beamformers

Abstract: Communication, medical diagnosis, radar, and speech processing applications involve wideband signals. Wideband beamforming is done by choosing a suitable array geometry and changing the weights given to each sensor under specified constraints. One of the main challenges of designing a wideband beamformer is maintaining a constant beamwidth over a wide range of frequencies. In standard beamforming methods, the mainlobe narrows as the frequency increases, necessitating an accurate direction-of-arrival estimation to avoid output signal distortion. Accurate real-time direction-of-arrival estimation is computationally expensive and challenging, especially in dynamic noisy reverberant environments with multiple moving sources. This talk is focused on wideband beamformers with broad constant beamwidths, eliminating the need to estimate the direction of arrival accurately. Our first example is a constant-beamwidth beamformer with predefined ring locations and weighting window functions. To determine the optimal weight values, we define an optimization problem. A nonuniform constant-beamwidth beamformer with variable ring locations and attenuation values is also presented. Circular ring array geometry and its potential in physical setups are illustrated by design considerations, theoretical analysis, and performance comparisons.

Brief Bio of Speaker: Israel Cohen is the Louis and Samuel Seiden Professor of electrical and computer engineering at the Technion–Israel Institute of Technology. He is an IEEE Fellow and served as a Distinguished Lecturer of the IEEE Signal Processing Society. He is a co-editor of the Multichannel Speech Processing Section of the Springer Handbook of Speech Processing, and a coauthor of Fundamentals of Signal Enhancement and Array Signal Processing (Wiley-IEEE Press, 2018). He was awarded an Honorary Doctorate from Karunya Institute of Technology and Sciences, the Norman Seiden Prize for Academic Excellence, the Alexander Goldberg Prize for Excellence in Research, and the Muriel and David Jacknow Award for Excellence in Teaching.