Comparison of diversity gain performance of single element dual-feed PIFAs with assorted MIMO antennas

Planar Inverted F Antennas (PIFAs) are commonly used in portable applications due to their attractive features. There exists a huge demand to use these PIFAs as MIMO or diversity antennas to allow for an increase in data rates or signal quality and to combat the shallow fading minima that exist in a multipath propagation environment with a non line of sight path. Recently, two new single element dual feed PIFAs have been developed at Liverpool; but are mainly investigated theoretically and numerically with limited experimental results. This paper presents a further study of these antennas; in particular, the diversity gain is measured using a large reverberation chamber, and the results are compared to some other MIMO/diversity antennas reported in literature. Furthermore, the trade-off between the miniaturisation and diversity gain is also investigated. It is also shown that a 24% increase in diversity gain can be achieved using cross-polarised feeding as compared to a co-polarised fed configuration.