Secure directional modulation using frequency diverse array antenna

Inspired by the frequency diverse array (FDA) producing range and angle dependent beampattern due to the employment of frequency increments across the array elements, this paper proposes a direction-dependent communications using 2-bit phase control across a two-element FDA antenna. The produced directional pattern projects the phase modulation signal as a constellation, which offers physical-layer security for wireless communications. This is because the transmitted symbols can be purposely distorted in other positions, but they could be successfully decoded at the intended range and angle position. The effectiveness of the proposed method is verified by numerical results.