Introduction of a sharp steerable null response in an otherwise omni-directional pattern using a circular array

A method of generating a single sharp null response in an otherwise omni-directional pattern using a circular array is discussed. The null width is reduced by the introduction of an abrupt phase reversal in the pattern function in the direction of the null. The null is also electronically steerable in the azimuth and in the elevation plane. Mutual coupling effect on the depth of the null is minimized through the use of sequence excitation components in the feed.