Antenna Diversity Performance in Mitigating the Effects of Portable Radiotelephone Orientation and Multipath Propagation

Antenna diversity can mitigate signal impairments caused by random angular orientation and multipath radio propagation when using portable radiotelephones. Cumulative distributions of signal-to-noise ratio (
S/N
) were determined for antenna diversity using realistic orientation and multipath propagation models. In a random orientation and multipath propagation environment with -6 dB average crosspolarization coupling, two-branch selection diversity with two perpendicular antennas yields an
S/N
distribution with the same slope as two-branch selection diversity in the fixed-oriented mobile radio environment. The distribution for random orientation is about 4.5 dB worse, however, than the mobile radio distribution.