Front-end non-linear distortion and array beamforming

Nonlinear distortion in RF front-end electronics can limit processing gain of digitized signals. Sensor array processing imparts spatial selectivity in capturing desired weak signals in the presence of interfering sources and spatially distributed noise. In this paper we examine the impact of non-linear distortion associated with realizable array systems on array beamforming algorithm performance that is referenced to perfectly linear systems. We show that for unfavorable system configurations nonlinear distortion can limit the gain that an array may impart in capturing weak signals, and can deny an array look directions that its ideal counterpart would otherwise capture. We use these results to motivate digital-domain non-linearity equalization.