Fuzzy Entropy for Frequency Diverse Array Beampattern Synthesis

Abstract

Frequency diverse array (FDA) can generate a range-angle-dependent beampattern due to the introduction of the tiny frequency offsets across array elements. However, the range-angle-coupled beampattern is detrimental to the estimation of the target parameter, and even the normal function of the FDA. In fact, the main purpose of the FDA beampattern synthesis is to achieve beampattern decoupling, mainlobe attenuation avoidance, and sidelobe suppression. Furthermore, these conditions can be summarized as the chaotic degree modulation of the beampattern. In this communication, the 2-D fuzzy entropy is first employed in the FDA beampattern synthesis. The proposed FDA can generate a dot-shaped beampattern with high fuzzy entropy in the near-target field and low fuzzy entropy in the far-target field. In addition, by introducing time-variant weights, the time modulation is suppressed in the fuzzy entropy-based FDA (FEBFDA). The results of the numerical simulation demonstrate the superiority of the proposed beampattern synthesis method.