Adaptive Array with Limiter in Feedback Path Preliminary Results

Abstract

The Hughes experimental multiple-element adaptive array antenna system is based on a hybrid implementation of Widrow's LMS algorithm. A microcomputer samples the analog correlator outputs, then computes the new antenna weight settings and updates the quadrature weighting circuitries accordingly. A hard limiter placed in the feedback path prevents permanent capture by the strongest interference. This configuration appears to circumvent the difficulty in nulling against multiple interferences. Laboratory results demonstrate up to 60 dB cancellation of jammers in a few hundred iterations. System performance degrades to about 30 dB suppression for a 12 percent bandwidth jammer.