Transmit Beamforming Based on 4-D Antenna Arrays for Low Probability of Intercept Systems

This article has developed a new approach to combine transmit beamforming techniques and 4-D antenna array theory for simultaneously improving the detection and low probability of intercept (LPI) capabilities of radar. This new approach enjoys most of the advantages of multiple-input multiple-output (MIMO) and phased arrays, providing excellent detection and LPI capabilities. The essence of the proposed approach is to utilize a 4-D variable to extend the detection dimension and increase the signal uncertainty. Specifically, the flexible choices of a time-modulation scheme can greatly improve the detection and LPI capabilities of radar. The substantial improvements achieved by the proposed method compared with basic MIMO and phased-MIMO arrays are demonstrated by simulations through analyzing the corresponding beampatterns. In addition, a basic experiment with reference to transmit beampatterns of 4-D antenna arrays is presented to validate the effectiveness of the proposed method.