Electrically Small Multimodal 3D Beamforming MIMO Antenna for PHY-Layer Security

Abstract

This work proposes an electrically small 3D beamforming antenna for PHYsical Layer (PHY-layer) security. The antenna comprises two layers of stacked patch structures and is a five-mode five-port MIMO system operating around 1.85 GHz with electrical size $ka=0.98$ and radiation efficiency of up to $55\%$. By studying the properties of the excited modes, phase and amplitude control allow for unidirectional beam scanning towards any direction around the elevation and azimuth planes. PHY-layer security is investigated using the directional modulation (DM) technique, which transmits unscrambled baseband constellation symbols to a pre-specified secure direction while simultaneously spatially distorting the same constellations in all other directions. Bit Error Rate (BER) calculations reveal very low values of $2\times 10^{-5}$ for the desired direction of the legitimate receiver, with BER$<10^{-2}$ beamwidths of $55^{\circ }$ and $58^{\circ }$ for the azimuth and elevation planes, respectively.

Conference paper