Range-angle-dependent beamforming for FDA-MIMO radar using oblique projection

Frequency diverse array(FDA)-multiple-input and multiple-output(MIMO) radar is characterized with a range-angle-dependent transceive beampattern by introducing incremental frequencies among the transmit array elements and separating the transmitted waveforms with matched filtering in the receiver. In this respect, the paper aims to control the range-angle-dependent transceive beampattern for FDA-MIMO radar by designing the weight vector according to the desired response. At the design stage, the weight vectors to control the beampattern responses of different regions are devised by performing the orthogonal decomposition technique. Then, a filtering matrix using the oblique projection operator is constructed to filter the weight vectors for different regions, where two iterative algorithms are developed either considering concurrent or successive control of multiple regions. In such a way, a desired range-angle-dependent transceive beampattern is formed with simultaneously broadened nulls and a flat-top mainlobe. At the analysis stage,the method has been applied to interference mitigation in FDA-MIMO radar, where the mismatch exists both in the sidelobes and mainlobe. Simulated and measured results are provided to corroborate the effectiveness of the proposed methods.