Due to the range-angle-dependent beampattern, frequency diverse array (FDA), either in the form of linear array or planar array, has been extensively investigated in recent years. However, the conformal FDA is seldom studied. In this article, a general conformal FDA framework is first developed. Specifically, a hemi-spherical FDA is exploited to illustrate the unique advantage of conformal FDA in terms of the 3-D localization ability. Furthermore, to deal with the intrinsic defect of time-variant range–angle-coupled beampattern of the FDA, an optimized static nonlinear frequency offset (OSNFO) is proposed. The OSNFO not only decouples the conformal FDA beampattern in the range–angle dimension, but also copes with its inherent time-variant problem, resulting in a quasi-time-invariant 3-D focusing beampattern. Numerous simulation results have been provided to demonstrate the superiority and the effectiveness of the OSNFO-conformal FDA.

中文翻译：

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共形频分阵列的准时不变三维聚焦波束图合成

由于依赖于距离角的波束模式，近年来广泛研究了线性阵列或平面阵列形式的频率分集阵列 (FDA)。然而，很少研究适形FDA。在本文中，首先开发了一个通用的共形 FDA 框架。具体而言，利用半球形 FDA 来说明保形 FDA 在 3-D 定位能力方面的独特优势。此外，为了解决 FDA 的时变距离-角度耦合波束图的固有缺陷，提出了一种优化的静态非线性频率偏移（OSNFO）。OSNFO 不仅在距离-角度维度上解耦了共形 FDA 波束图，而且还解决了其固有的时变问题，从而产生了准时不变的 3-D 聚焦波束图。