The phase-only shaping and adaptive nulling of an amplitude pattern

An efficient phase-only control method is reported for shaping a given antenna array amplitude pattern and simultaneously placing adaptive nulls in unknown interference directions. The method iteratively minimizes a functional (that incorporates constraints imposed on the desired pattern shape and power measured at the array output) with respect to phases of the array element excitations and to the phase of the given amplitude pattern by a coordinate-by-coordinate (single-coordinate) method that finds the minimum along each coordinate by a closed-form formula using three power measurements per one iteration. The method shows fast convergence, is stable to phase shifter errors, and complies with the digital phase control. Results of computer modeling are provided.