Generalised selection combining diversity performance of multi-element antenna systems via a stochastic electromagnetic-circuit methodology

A stochastic electromagnetic-circuit methodology for evaluating the generalised selection combining (GSC) diversity performance of coupled and arbitrarily terminated multi-element antenna (MEA) systems when operating in Rayleigh fading environments is proposed. The methodology is based on the effective length matrix, which connects the incident electric fields to the received voltage and current vectors, and on the newly introduced stochastic generation of realistic propagation environments by means of the angular power density functions and the cross polarisation power ratio of the incoming plane waves. The generated statistical ensemble of voltage and current vectors is then used to determine the receive GSC diversity performance metrics, that is mean effective gain (MEG), envelope correlation coefficient (ρ_e) and effective diversity gain (EDG). Two compact MEA configurations comprising two and four printed inverted F antennas (IFA) operating in a uniform propagation scenario at the 5.2 GHz band are investigated under various GSC schemes, which include the selection (SC) and the maximal ratio (MRC) as special cases. The simulated values of MEG, _e and EDG under the MRC scheme are in excellent agreement to those obtained from well-established closed-form methodologies.