Abstract：Some research is made for the uncertainty of normalized antenna radiation pattern (only amplitude) from NIM precise spherical near-field (SNF) antenna measurement facility (400 MHz to 110 GHz). There are 18 uncertainty items from probe, mounting, data sampling and radio-frequency system are introduced in brief, based on "self-comparison approach". A detail "perturbation method" is proposed to evaluate the scattering from the anechoic chamber based on the ray-tracing method; it is known that sometimes it is impossible to move the spherical system in the anechoic chamber to evaluate the scattering from the absorber. The evaluation results show that for NIM’s SNF facility, when the side lobe up to -40 dB, the repeatability is less than 0.1 dB (26GHz), and the expanded uncertainty for a normalized radiation pattern (amplitude) is 2.7 dB when ignoring the cross-polarization of the probe. Finally, the uncertainty characteristics of a SNF facility is summarized.
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2017, Vol. 38 
