Effect of Polarization on RF Signal Transmission over Two-Ray Channel

This paper presents a practical two-ray model which accurately characterize the receiver power compared to conventional two-ray model for wireless communication and power transfer applications. The proposed model considers the impact of polarization orientations of line of sight (LOS) and non-line of sight (NLOS) components, and complex permittivity of the reflecting surface. On observing the received power for various different environmental settings (different source and receiver heights, transmission distance and reflector permittivity), it becomes apparent that the best suited polarization for maximum power reception alters between horizontal and vertical polarization in a single transmitter system. We show that when heights of transmitter and receiver and transmission distance are nearly same then vertical polarization provides relatively stable power. However, in arbitrary settings, for short range communication horizontal polarization is capable of delivering large power. We demonstrate that the over large communication distances, all polarization angles perform nearly identically. Additionally, we show theoretically that reflection may not only change orientation angle but may also alter the state of polarization of NLOS component.