天线平面近场测量的研究(一)

<正> 一、问题的提出为节省星上射频功率、减少对邻国的干扰,考虑到我国版图的具体情况,广播卫星采用多馈源抛物面天线的成形波束设计。有关该天线辐射和复盖性能分析参见。我国广播卫星电视传送频段拟用Ku波段(12/14GHZ),数值计算表明反射面天线口径一般都超过一米。多馈源抛物面成形波束的设计基础是利用偏焦馈源的二次波束偏斜。恰当设计馈源数目和它们在焦平面上位置及相对激励系数,就可得到按预定空间分布的各子波束。这些子波束

STUDY OF PLANAR NEAR-FIELD MEASUREMENTS OF ANTENNAS

This paper first describes a necessity of far-field constructed from near-field measurements for the future satellite's antennas. The first part of this paper discusses a plan-polar near-field technique. By means of the Lorentz reciprocity theorem and The Jacobi-Bessel series expansion the transform formulas from near-field to far-field have been developed. Once the phase and amplitude distributions are sampled by a scanning probe in a plane-polar configuration, the measured data may be transformed into the far radiataed field using the above formulas. Finally, an automated planar near-field measurement system program-controlled by a microcomputer is presented.In the second part of this paper we have summarized some recent results in NBS on upper-Bound errors in far-field antenna paramefers determined from planar near field measurements. Some important formulas and relationships are presented. They may be used for evaluating the maximum errors of far-field paramefers produced by planar nearsfield measurements.They also can provide useful guidelines for design of near-field measurement technique.