ABSTRACT This paper, considering the tilt effect, presents a hemispherical antenna structure modeled by an improved conformal antenna array with the maximum angular coverage of the elevation axis to increase the Direction-of-Arrival (DOA) estimation accuracy. For this purpose, a multiface conformal structure with 3 different tilts and 13 directive circular patch antennas is designed in the Full Wave Simulation Software (HFSS). By optimizing the angles α and β as two key parameters in this design, nine different structures are constructed and their impacts on the DOA performance are carefully studied. The Cramer–Rao Lower Bound (CRLB), Multiple Signal Classification (MUSIC), and Root Mean Square Error (RMSE) algorithms are utilized to evaluate all constructed structures and chose the most improved structure for DOA estimation. At the end, it is shown that the proposed hemispherical antenna structure has a better performance than previous conformal designs for DOA applications and spatial resource positioning in which the maximum elevation angle coverage by the antenna is highly required. It is noted that the tilt optimization method proposed in this paper can lead to design a near optimal conformal antenna array structure for DOA estimation for a wide elevation angle coverage which can be considered for next works.

中文翻译：

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通过倾斜校正合成共形天线阵列辐射方向图以提高到达方向估计精度

摘要 本文考虑到倾斜效应，提出了一种由改进的共形天线阵列建模的半球天线结构，该天线阵列具有仰角轴的最大角度覆盖范围，以提高到达方向 (DOA) 估计精度。为此，在全波仿真软件 (HFSS) 中设计了具有 3 个不同倾角和 13 个定向圆形贴片天线的多面共形结构。通过优化角度 α 和 β 作为该设计中的两个关键参数，构建了九种不同的结构，并仔细研究了它们对 DOA 性能的影响。Cramer-Rao 下界 (CRLB)、多信号分类 (MUSIC) 和均方根误差 (RMSE) 算法用于评估所有构造的结构并选择最改进的结构进行 DOA 估计。在最后，结果表明，对于 DOA 应用和空间资源定位（其中高度要求天线的最大仰角覆盖范围），所提出的半球天线结构比以前的共形设计具有更好的性能。值得注意的是，本文提出的倾斜优化方法可以设计出一个接近最优的共形天线阵列结构，用于广仰角覆盖的 DOA 估计，可以考虑用于下一步工作。