Merger of polarization and spatial diversity by moving a pair of orthogonally polarized dipoles

Abstract

Size and cost considerations of handheld terminals limit the use of antenna array for combating multipath fading in these applications. Recently, a synthetic array based on moving a single antenna was proposed for handheld terminals. This technique however fails to provide enough diversity gain when the channel is spatially correlated. A combination technique based on merging polarization and spatial diversity and motions of a crossed dipole is proposed here. The diversity performance of the crossed dipole synthetic array (XSA) is then compared to that of a single dipole synthetic array. A closed form expression is also derived for calculating the cumulative distribution function of summation of correlated central chi-squared random variables with four degrees of freedom which arises in the XSA performance analysis. Finally, the proposed technique is put into test through an extensive set of measurements.