Theory of Secure Antenna Polarization Modulation

Secure Antenna Polarization Modulation, or SAPM, is a method for increasing system security at the physical layer via spatial signal distortion. In this work, we derive its theoretical performance limits and compare these to simulations using an additive white Gaussian noise (AWGN) channel model. We evaluate SAPM in the context of security-related characteristics, like information beamwidths and secrecy rates, benchmarking its performance to other secure techniques like directional modulation. The results indicate that SAPM generally performs better, with more significant margin in lower noise floor environments and when using higher orders of modulation.