Adaptive broadband beamforming using phase-independent derivative constraint techniques

A method is presented to achieve flat mainbeam responses by imposing phase-independent derivative constraints. In contrast to the conventional derivative constraint methods which constrain both the magnitude and phase response, the proposed method only constrains the magnitude response. Previous results for up to the second order derivatives reported by the authors have indicated that flat mainbeam responses can be generated with much more appealing sidelobe levels by use of the phase-independent derivative constraints than those generated by use of the conventional derivative constraints. The results are further generalized to cases with arbitrarily high order derivatives. The application of these phase-independent derivative constraint techniques in adaptive broadband beamforming is also discussed.<>