偏馈抛物面天线方向图外场测试分析

Outfield test analysis of offset-fed parabolic reflector antenna

基于口径场法,提出了地基偏馈抛物面天线方向图的数值计算模型,分别给出了自由空间和镜面多径反射情况下的偏馈抛物面天线方向图,分析了测试距离对水平和垂直方向图的波瓣分布和增益的影响;同时分别仿真了固定测试距离情况下,偏馈抛物面天线镜面反射方向图随仰角和高度的变化规律。外场测试结果验证了仿真模型的正确性。该仿真模型能解释不同测试条件下,天线外场方向图的波瓣分布特点,对天线外场测试设计、性能评估和测试误差分析有一定的指导意义。

Based on the aperture field method, the numerical antenna pattern simulation model is presented for ground based offset fed parabolic reflector. On the conditions of free space and mirror reflecting, the offset fed parabolic reflector antenna patterns are calculated respectively. The influences on beam lobe and gain of different test distances＇ are analyzed for horizontal and vertical antenna patterns. Then the laws of antenna mirror reflecting patterns changing with elevation angle and altitude are simulated for the fixed test distance. The simulation model presen- ted is testified by outfield test results. The simulation model can explain the beam lobe distributed characteristic of outfield antenna pattern at different test conditions, and may be used to direct the outfield antenna test design, performance evaluation and measurement error analysis.