Compensating for the mutual coupling effect in a normal-mode helical antenna array for adaptive nulling

Abstract

A practical normal-mode helical antenna array together with a new method for the compensation of the mutual coupling effect is proposed for the efficient adaptive nulling of interferences in a mobile communication environment. The helical antenna array is shown to be able to generate deeper nulls than an equivalent monopole antenna array in the presence of the mutual coupling effect. The helical antenna elements are smaller in size and less susceptible to the mutual coupling effect than monopole antenna elements. The new method for compensation of the mutual coupling effect is shown to have a greater ability and flexibility than previous methods. A new definition of mutual impedance is introduced and used to find the coupling-free signal voltages across the antenna terminal loads. Numerical examples demonstrate the superior performance of the proposed adaptive array and the new compensation method.