LPI/LPD Communications Using Antenna Arrays with Rapid Side Lobe Time Modulation

We present a method for realizing low probability of intercept/detect (LPI/LPD) secure communications. The proposed method relies on the rapid side-lobe time modulation (SLTM) achieved by a linear antenna array providing fast beam forming and shaping. Leveraging the SLTM, the signal transmitted in the side-lobe directions is scrambled while the signal in the main lobe direction is not significantly changed. We also design a 1-bit reconfigurable patch antenna, embedded with two high-speed PIN diode switches, as the array element. By pseudorandomly and alternatively controlling the array elements at high speed, the signal radiated from the SLTM array is unchanged in the main lobe direction but is completely distorted along the side-lobe directions.