传输线反向辐射对标准噪声源定标的影响

The Influence of Backward Radiation on Evaluating the Standard Noise Source

分析了传输线反向辐射对微波标准噪声源定标的影响。根据经典的定标方程导出了相应的扩展定标方程。计算了匹配负载在不同反射系数下传输线反向辐射对定标结果的影响量。结果表明如果匹配负载的反射系数在0到0.03之间,传输线反向辐射对定标值的影响小于1‰,实际应用中当匹配负载的反射系数大于0.03,可以通过扩展定标方程得到更为精确的定标结果。

The influence of the backward radiation of the transmission line on the evaluation of the microwavestandard noise source is analyzed. infuence quantity of the backward An extension formula is deduced based on the classical evaluation formula. The radiation versus the reflection of the matched load is calculated base on the extension formula. The results show that the influence quantity is within 1%o if the reflectivity of the matched load is on the range of 0 to 0. 03. The accurate evaluation results can be gotten by using the extension formula when the refectivity of the matched load is large than 0.03.