Effect of interchannel mismatches upon adaptive array cancellation

The author analyzes the effect of interchannel mismatch on adaptive array interference cancellation for an arbitrary number of channels and arbitrary bandwidth waveforms for a partially adaptive array used in a multiple sidelobe canceller (MSLC). A general equation giving the residue power as a function of the interchannel mismatch, the radar bandwidth, and the array parameters is derived. To aid in clarifying the dependence of cancellation on interchannel errors, a Taylor series expansion is obtained. It shows that the ratio of adapted power to the unadapted main power is greater than 1-μ (where μ is the average interchannel mismatch correlation coefficient) for all interferer locations and power levels and any number of auxiliary antennas. The special, simple-geometry case of narrowband orthogonal direction vectors is evaluated. For this case, the ratio of adapted to unadapted power is approximately equal to (1-μ)(1+K/N ) for K interferers and N auxiliary antennas