Simultaneous nulling in the sum and difference patterns of a monopulse antenna

Most adaptive array research has not directly addressed the problem of nulling in a monopulse antenna. Placing a null in the sum does not automatically place a null in the difference pattern and vice versa. Nulls may be placed in the two patterns with the use of separate adaptive weights and controls for the sum and difference channels. However, this requires two sets of adaptive hardware for one antenna. A technique for simultaneous nulling in the sum and difference channels of a monopulse phased array using one set of adaptive weights shared by both channels is described. First, the technique is described for amplitude and phase nulling, then for phase only nulling. In each case, the ability to simultaneously null in both channels with one set of variable weights is theoretically demonstrated.