WR-28功率基准系统中等效源反射系数校准研究

在WR-28功率基准系统中,等效源反射系数是确定量热计有效效率、分析不确定度与进行基准功率量值传递的重要参数,其只与接入量热计的定向耦合器有关,而与信号源无关。介绍了传统三端口测试法、直接校准法和最新提出的Shimaoka K法3种三端口器件等效源反射系数的测试方法。在频段26.5~40 GHz,运用Shimaoka K法对三端口器件（定向耦合器）进行等效源反射系数测量,并与其他两种方法实验结果比较,验证了Shimaoka K法的可行性与准确性,同时通过实验比较,由于Shimaoka K法具有的综合优势,使其成为WR-28功率基准中等效源反射系数的最佳测试方法,并以Shimaoka K法为例,对等效源反射系数不确定度进行了评定。

Research on Calibration of the Equivalent Source Reflection Coefficient in WR-28 Power Standard System

The equivalent source reflection coefficient is an important parameter to determine the effective efficiency of the calorimeter and analyze the uncertainties and transfer power standard in WR-28 power in the reference system. And it is irrespective of the signal generator in this power system,only depends on the directional coupler connected with the calorimeter.Three measurement methods: traditional three ports method,the direct calibration method and Shimaoka K method are introduced.The experiments are first operated with Shimaoka K method in 26.5~40 GHz,to measure the equivalent source reflection coefficient of the directional coupler.The best method is determined by analyzing and comparing the results obtained from the three methods.The experiment results show that Shimaoka K method is not only feasible,but also the best choice in WR-28 power standard system due to its comprehensive advantages.The uncertainty of equivalent source reflection measurement is also evaluated by the Shimaoka K method.