Adaptive Phase-Shifter Nulling Techniques for Large-Aperture Phased Arrays
NAVAL RESEARCH LAB WASHINGTON DC
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Several simple phase-shifter nulling techniques are investigated for application to large-aperture phased arrays to provide a modest, partial adaptive capability at reasonable cost. These techniques do not require auxiliary elements, correlators, or beamformers, but they do require access to the array element phase shifters for injection of small phase perturbations. They also require a priori knowledge of interference source directions to facilitate fast cancellation. Particular aperture ripple modulation algorithms, based on beamspace decomposition principles and adaptive search techniques, are described and applied to computer simulated source situations. For example, by using a 16 element linear array, two strong sources of 5 bandwidth were nulled out within about 600 snapshots range bins of data this is remarkably fast for such a simple phase-only adaptive system. The performance results achieved indicate that the concept is feasible and ready for experimental phased-array verification.
- Electrical and Electronic Equipment
- Radiofrequency Wave Propagation