A high-directivity combined self-beam/null-steering array for secure point-to-point communications

A high-directivity combined self-beam/null-steering array for secure point-to-point binary phase-shift keying communications is introduced. The system provides high directivity and reduced probability of interception using just two antenna elements. Using quadrature phase-shift keying modulators allows for compact single-layer fabrication. The 2.4-GHz prototype is tested at interrogation angles of 0[degrees], -10[degrees], and +20[degrees], and demonstrates high signal-to-interference ratio directivity, completely disabling interception [+ or -]20[degrees] from the direction of the interrogator. The system should find various applications where secure communications are required. Index Terms--Digital communication, microwave receivers, phase conjugation, phased arrays, transponders. Digital Object Identifier 10.1109/TMTT.2007.895405