Joint Optimization of Sparse FDAs for Time Invariant Transmit Beampattern Synthesis

Beampattern synthesis of frequency diverse arrays (FDAs) has recently raised increased attention attributed to their range-dependent beampattern. The transmit beampattern of uniform FDA appears S-shaped, which implies coupling in the range-angle domain and thus causing unwanted energy leakage into the area of non-interest. In this work, we propose a joint optimization of sparse FDAs to synthesize a decoupled transmit beampattern from the perspective of spatial-frequency virtual array. Specifically, both spatial and spectral configuration of FDAs are optimized via joint antenna-frequency selection. In order to solve the resultant NP-hard combinatorial optimization problem, we propose an iterative reweighting strategy to transform the original problem into a convex optimization. Further, we proceed to synthesize a time-invariant decoupled beampattern by designing a time-varying unit frequency step. Comparative simulations are provided to manifest the superior performance of the proposed FDA in the metric of normalized peak sidelobe level (NPSLL) of transmit beampatterns.

Automated summary

In this paper, a joint optimization method for sparse FDAs is proposed to synthesize a decoupled transmit beampattern from the perspective of spatial-frequency virtual array. By optimizing the antenna and frequency selection, the NP-hard combinatorial optimization problem is solved, and a time-invariant decoupled beampattern is synthesized by designing a time-varying unit frequency step.