日像仪观测太阳射电信号左右旋圆偏振的方法

摘要

使用Microwave Office软件,仿真分析MUSER-I (0.4～2 GHz)和MUSER-II(2 ～15 GHz)3 dB定向耦合器.电桥采用多节耦合器实现,且每节耦合器的长度为中心频率波长的1/4,对电桥进行分析并制作实物,实测结果表明,MUSER-I的3 dB定向耦合器的输出幅度在(-3±0.2)dB,输出端口相位差在91.9°～89°之间;MUSER-II的3 dB定向耦合器的电压驻波比在全频带范围内小于1.31,输出端口相位差在96.05°～85°之间.通过日像仪系统接收太阳左旋和右旋圆偏振射电信号,并计算信号的圆偏振度,得到观测圆偏振度与太阳信号本身圆偏振度之间的误差和太阳信号本身偏振度的关系.当太阳信号本身极化度为10％时,误差最大为9.4％.%The 3 dB couplers of MUSER-I and MUSER-II are simulated using Microwave office software.Because of the ultra wide frequency band,multiple single couplers are used to synthesis one symmetrical coupler.The amplitude of MUSER-I 3 dB hybrid is (-3 ± 0.2) dB,and the phase difference of this port is between 91.9° and 89°.For MUSER-II 3 dB hybrid,the voltage standing wave ratio is less than 1.31 and the phase difference is between 96.05° and 85°.This radioheliograph receives left and right circularly polarized radio signals.The difference between the polarization degree of the Sun and the observed polarization degree is also measured,and the error is 9.4％ when the original polarization degree is 10％.