Characterisation of electromagnetically coupled superquadric loop antennas for mobile communications applications

Abstract

Analysis of two mutually coupled loop antennas with arbitrary relative orientation and position and possibly different geometries is presented. The antennas are represented by generalised superquadric curves, which include circular, elliptical, and rectangular loop geometries, and they may be located either in a homogeneous region or next to an infinite ground plane. A Galerkin-type moment method with piecewise sinusoidal subsectional basis and weighting functions is used. Special consideration is given to implement the solution using curved wire segments instead of the commonly employed linear segments to improve computational efficiency. This very general computational tool is used to investigate the behaviour of coupled loops in configurations suitable for personal communications applications. A discussion of the use of antenna diversity to increase the received signal-to-noise ratio for communications equipment used in a multipath fading environment is also presented. Computational examples show that antenna diversity can provide significant improvements even for closely spaced loop antennas used in mobile communications applications.