Frequency Diverse Array Antennas with Random Logarithmically Increasing Frequency Offset

Due to its range-angle-dependent transmit beampattern, frequency diverse array (FDA) provides potential applications for physical layer secure communication. However, a standard FDA using linearly increasing frequency increments will generate range and angle-coupled S-shaped beampattern; i.e., eavesdropper which locate at other angle-range pairs can also effectively receive the confidential message.. This paper proposes a focused beampattern synthesis by employing random logarithmic frequency increments. Simulation results show the random logarithmic frequency array can form a point beam with more concentrated energy, lower sidelobe energy, and higher resolution in range and angle dimensions without increasing the system bandwidth.