Transmit Beampattern Synthesis for Frequency Diverse Array With Particle Swarm Frequency Offset Optimization

Different from the conventional phased array radar, a frequency diverse array (FDA) applies additional frequency shift across the array elements, yielding a range-angle-dependent transmit beampattern that provides a huge potential opportunity for target estimation and range-dependent clutter and interference suppression. Generally, the conventional FDA employs a linear small frequency increment, forming a time-varying "S"-shape range-angle beampattern, which is range-angle coupled. In this article, a range-angle transmit beampattern synthesis method for FDA based on frequency offset optimization is proposed. Particle swarm optimization (PSO) is adopted in the FDA element frequency increment design to achieve a dot-shaped transmit beampattern. Meanwhile, matched weights are designed for time-modulation compensation. Numerical simulation results demonstrate that the proposed approach achieves better time-invariant performance over other FDA frameworks.