Gain maximization and controlled null placement simultaneously achieved in aerial array patterns

This paper presents a matrix method for maximizing aerial directive gain, while simultaneously placing nulls in the far-field radiation pattern of the array. The technique is applicable to aerial arrays of N elements, arbitrarily positioned, and allows the designer to specify the directions of up to (N¿1) independent pattern nulls and/or side-lobes, while providing maximum gain in some prespecified direction. This control is achieved by varying only the amplitude and phase of the element currents. The method can be used even when non-isotropic aerial elements and interelement mutual coupling effects are included in the expression for directive gain.