Near-field radio holography has been successfully applied to the slant-axis terahertz antenna, which features a unique rotational-mechanism. Corrections of residual path length errors and parallax effect caused by the noncoincidence of the aperture center and rotational center of the antenna are analyzed in detail for high precision near-field holographic measurement conducted at very short distances. Particular discussions are also provided about nonuniform sampling and polarization mismatch errors resulted from the beam rotation of the slant-axis mount system. Precise surface measurement and alignment have been demonstrated on a 1.2 m diameter slant-axis antenna, designed as the scaled model of the 5 m Dome A Terahertz Telescope. Experimental results with a root mean square of measurement repeatability better than 2.0 μm has been obtained.

中文翻译：

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斜轴太赫兹天线的近场无线电全息术

近场无线电全息技术已成功应用于斜轴太赫兹天线，该天线具有独特的旋转机制。详细分析了天线孔径中心与旋转中心不重合导致的残余路径长度误差和视差效应的校正，以实现在极短距离下进行的高精度近场全息测量。还特别讨论了由斜轴安装系统的光束旋转导致的非均匀采样和偏振失配误差。已在直径为 1.2 m 的斜轴天线上演示了精确的表面测量和校准，该天线设计为 5 m 圆顶 A 太赫兹望远镜的缩放模型。已获得测量重复性均方根优于 2.0 μm 的实验结果。