Multiple Nulls Synthesis for Circular Arrays Using Least Squares Method

This paper presents the feasibility of the least squares (LS) based methods in synthesis of multiple nulls in the omnidirectional radiation pattern of circular array antennas. To this purpose, an ideal pattern with an abrupt phase reversal at the angular location of desired nulls is effectively incorporated within the proposed framework. The effects of number of elements and interelement spacing on the characteristics of the radiation pattern are studied. Results demonstrate the presented paradigm provides narrower nulls at the expense of tolerable increment in gain ripple value.