On the Applications of the Frequency-Response Masking Technique in Array Beamforming

The frequency-response masking (FRM) technique is well known to be very efficient in the implementation of finite impulse response (FIR) filters with sharp transition bands. As sensor array beamforming is closely related to FIR filtering, the feasibility of the applications of the FRM technique in array beamforming is investigated in detail in this paper. On one hand, it is shown that there is a limitation in applying the FRM technique in passive array beamforming. On the other hand, for active array beamforming, a novel combination of the concept of effective aperture and the FRM technique does lead to the synthesis of desirable beamformers. These beamformers have effective beampatterns with sharp transition bands and low sidelobes, and can be implemented with fewer sensors than other design techniques.