Termination-Dependent Diversity Performance of Coupled Antennas: Network Theory Analysis

Abstract

A new analysis of mutually coupled diversity antenna systems is presented that includes the effects of coupling on the radiation pattern and received power. This analysis, based upon the network scattering parameters, makes use of the singular value decomposition to both specify the characteristics of and analyze terminated antenna networks. The approach facilitates a simplified proof of the multiport conjugate matching condition as well as development of expressions for diversity performance as a function of various impedance terminations. Application of the analysis to coupled dipole antennas characterized using full-wave electromagnetic analysis leads to a comprehensive examination of the diversity performance obtainable for such antennas under different termination conditions. The results from this paper reveal that for closely spaced antennas, the termination can play a noticeable role in determining the diversity gain offered by coupled antennas.

A mutual coupling model for massive MIMO applied to the 3GPP 3D channel model

“…When mutual coupling is included, correlation decreases faster with antenna separation even when no matching is included. Considering the coupled and matched case, the matching network is chosen to achieve a multiport conjugate match and ideal decorrelation, see [10], [12]. This solution is also provided in the appendix.…”

“…In contrast to previous work, we extend the coupling model by a matching network as a method for partly compensating mutual coupling effects. We consider a multiport conjugate match designed for optimal decorrelation [10], [12]. To show the effects of mutual coupling in a massive MIMO system, the coupling model is applied to the 3GPP 3D channel model [13] that does not consider antenna coupling by itself.…”

“…The matching network is designed to be lossless and reciprocal, therefore, S H M S M = E and S T M = S M where (·) H denotes the conjugate transpose. To achieve a multiport conjugate match [10], [12] the matching network is defined by…”

“…According to [10], [12] these quantities are chosen as D = iE, U 11 = E and V 11 = U 11 for perfect decorrelation.…”

On Some Optimal Mimo Antenna Coefficients in Multipath Channels

“…However, the joint characterization of transmit and receive antenna systems has only recently been treated in a rigorous manner [9,10]. In [11] the main focus has been on the characterization of mutual coupling of closely placed antenna elements.…”