Extended beamforming by sum and difference composite co-array for radio surveillance

This paper presents a way of extended digital beamforming technique by non-uniform array antenna used for radio surveillance. We try to enhance the array degree of freedom (DOF) by combining the concepts of extended (sum and difference) co-arrays, so that we can create a better beampattern with narrower mainbeam and more number of nulls. Performance of the proposed array configuration is evaluated through computer simulation of digital beamforming. We also study the way of modulation/demodulation which is effective for the extended arrays.