Mis-modeling and mis-correction of mutual coupling in an antenna array — A case study in the context of direction finding using a linear array of identical dipoles

Abstract

In an array of antennas, the inter-antenna electromagnetic mutual coupling, unless properly corrected, would degrade an antenna array's performance in direction finding. In the special case of a uniformly spaced linear array of identical antennas, Azarbar, Dadashzadeh & Bakshi have suggested discarding the antennas' collected data at both ends of the linear array, on the assumption that all middle antennas experience near-identical mutual coupling, as each middle antenna would have many antennas on either side. The antennas whose data will be discarded are called the “auxiliary” antennas. While Azarbar, Dadashzadeh & Bakshi modeled the mutual coupling matrix as Toeplitz and banded, this key assumption is invalidated by simulations using the “method of moments” (as realized in the software “EMCoS Antenna VLab”). Using such more realistic values for the mutual coupling matrix for a uniform linear array (ULA) of identical dipoles, instead of the idealistic assumptions of a Toeplitz banded mutual coupling matrix, the method in Azarbar, Dadashzadeh & Bakshi's paper is found here to perform very poorly.