New constraints for broadband beamformers without steering delays

In processing broadband signals using an array of sensors, the steering delays are inserted between the sensors and the tapped delay line filter to compensate for the effect of misalignment between the array geometry and the look direction. Selection of steering delay is practically difficult and may cause loss of performance if precise delays are not used. This paper presents a simple set of constraints which completely eliminate the need of steering delays. Using these constraints one is able to formulate a beamforming problem for a broadband element space time domain antenna array with a specified frequency response in any arbitrary direction without using steering delays.