Automatic Cross-Polar Discrimination Optimization System for Ku-band VSAT Antennas

This paper proposes a novel system for the optimization of the cross-polar discrimination (XPD) value of a Ku-band VSAT antenna. Firstly, the model of the signals received at the co- and cross-polar HUB output ports is derived. Based on this, the XPD optimization procedure is described, relying on the power measurement of specific signals received on the two ports. As the signal on the cross-polar output is received with a very low signal-to-noise ratio, its demodulation and power measurement are enabled by transmitting a highly spread spectrum signal. Also, the successive interference cancellation technique typical of the enhanced-spread spectrum access (E-SSA) protocol is here exploited to retrieve the useful signal on the cross-polar port. Finally, simulation results validate the proposed approach and preliminary on-field measurements show the operability of the system.