A least squares approach to the design of frequency invariant beamformers

A least squares formulation for the design of frequency invariant beamformers (FIBs) is proposed with two solutions provided. One is based on the Lagrange multipliers method and the other one is based on an orthogonal decomposition of the coefficient vector to transform the constrained design problem into an unconstrained one. Design examples including both broadside and off-broadside main beams are provided with satisfactory frequency invariant property and sidelobe attenuation.