Frequency Diverse Array Beampattern Synthesis With Sinc- and Weighted-Sinc-Function-Based Frequency Offsets

Frequency diverse array (FDA) has received much attention due to its capability of forming range-angle-dependent beampatterns. However, the standard FDA can only provide S-shaped beampatterns, leading to weakening the signal-to-interference-plus-noise ratio (SINR). Several window-based FDAs have been proposed to remove the coupling. However, the performance of these FDAs is limited by the use of conventional window functions, hindering further improvements. In this article, the "window-shaped" Sinc function (Sinc-FDA) is innovatively exploited into the frequency offset form to decouple the beampattern rather than using traditional window functions. Moreover, the sidelobe performance of existing window-based FDAs degrades in higher frequency offset bandwidth and wider observation area and is limited by the sidelobes near the main lobe. A weighted function is introduced to further flexibly suppress sidelobes, which forms a new weighted Sinc-FDA (W-Sinc-FDA). Simulation results compared with other optimization algorithm and function-based FDAs further demonstrate the effectiveness of the proposed Sinc-FDA and W-Sinc-FDA.