Directional Modulation Technique for Phased Arrays

TLDR

The paper presents a directional modulation technique that uses a phased array to generate modulation signals. The method achieves directional modulation by phase‑shifting each array element to shape the amplitude and phase of symbols toward a target direction, allowing independent data streams in multiple directions and enabling calculation‑based phase settings rather than extensive simulations. The technique provides directional security by distorting signals in unintended directions, and its effectiveness is demonstrated through mathematical analysis and experimental results.

Abstract

A directional modulation (DM) technique using a phased array to produce the modulation is presented. By phase shifting each element correctly, the desired amplitude and phase of each symbol in a digital modulation scheme can be produced in a given direction with data rates determined by the switching speed of the phase shifters. Because this signal is direction-dependent, the technique offers security, as the signal can be purposely distorted in other directions. DM also enables an array to send independent data in multiple directions. When using an array with driven elements, the phase shifts can be determined from simple calculations rather than time-consuming simulations or measurements. Mathematical analysis and experimental results are presented.