Pattern nulling in difference pattern by amplitude control

A method of placing nulls in directions of any unwanted radio frequency interference (RFI) sources in the difference pattern of a phased array by controlling the current amplitudes is discussed. Thus one can now achieve pattern nulling in both the sum and difference patterns by amplitude control and can therefore carry out the minimization of RFI noise independently of the maximization of the desired signal. The method therefore provides an efficient alternative approach to the design of adaptive phased arrays.