LPI Beamforming Based on 4-D Antenna Arrays With Pseudorandom Time Modulation

Traditional low probability of interception (LPI) design methods are mainly focused on the LPI waveform design. As a matter of fact, array design can also improve the LPI performance and is compatible with waveform design. A novel beamforming approach based on 4-D antenna arrays with pseudorandom time modulation is proposed for the effective improvement of LPI performance. The time sequences of 4-D arrays are designed as pseudorandom parameters and each element is modulated with a pseudorandom time sequence in order to hide the waveform parameters in undesired directions. A parameter estimation method including the time–frequency analysis is introduced for evaluating the performance of LPI. The numerical simulation results show that the LPI performance can be significantly improved in undesired directions by pseudorandomly modulating each element. Selected experimental verifications are performed and good agreement with the numerical results is obtained, thus validating the effectiveness of the proposed approach.