An adaptive beamformer is a beamforming system which performs adaptive spatial signal processing with an array of radar antennas (or phased array) in order to transmit or receive signals in different directions without having to mechanically steer the array. The main distinction between an adaptive beamformer and a conventional beamforming system is the ability of the former to adjust its performance to suit differences in its environment. A particularly important feature, in military applications, is the potential for an adaptive beamformer to reduce sensitivity to certain directions of arrival so as to counteract jamming by hostile transmissions.