Exploitation of Elliptical Polarization for Improved Orthogonal Static Links

Orthogonal static or fixed links with polarization multiplexing can be formed by using dual-polarized antennas with a low cross-coupling from one polarization to the other. This is limited by the level of achievable polarization purity of two orthogonal dual-polarized antennas. Any practical antenna is inherently elliptically polarized (EP), resulting in either circular or linear polarization (LP) impurity. This article exploits such impurity where simple semi-directional EP antennas are designed to have minimal cross-coupling. The results show that a dual polar static link can reach the capacity limit using EP, which is not reached with LP. Channel measurements in both free-space and indoor environments were carried out from 2.2 to 2.4 GHz using a derived cross-polar ratio to quantify the impact of multipath scattering on static links.