Investigations on the Effect of Mutual Coupling in Smart Antenna Using Adaptive Signal Processing Algorithm

Abstract

Adaptive beamforming is one of the most refined approaches in the recent times backed by a creditable signal processing unit to generate beam patterns in the desired direction in a dynamic cellular environment. The paper alludes to the effect of mutual coupling in the beamforming of a smart antenna of linear antenna array of isotropic elements. The effect of mutual coupling on the array parameters, like, desired beam direction (BD), half power beamwidth (HPBW), maximum side lobe level (SLLmax) are investigated by varying the inter-element spacing using adaptive signal processing least mean square (LMS) algorithm. The effect of mutual coupling is more dominate for lower inter-element spacing (d) causing the desired beam direction to shift by appreciable degrees. Below d<0.3λ, HPBW changes affecting the directivity of the array antenna.