级联滤波模块驻波比的规律探讨

Discussion on VSWR law of cascaded filtering module

级联滤波器模块在短波通信中起到至关重要的作用,而驻波比是其重要的性能指标。以带通滤波器和低噪声放大器组成的级联滤波模块为例,分析了级联网络中影响驻波比的因素,重点研究了低噪声放大器的S参量与整体驻波比的关系。通过矩阵变换推导得出公式,进而从三个方面分析出定性的规律表达式,对实践工作有积极的指导意义。

Cascade filtering module plays an important role in short-wave communication, and VSWR is a key performance index. Taking a cascade filtering module composed of band-pass filter and low noise amplifier （LNA） as an example, the main factor that impacts the VSWR in the cascade network is analyzed, and the relationship of S parameter and VSWR of low noise amplifieris studied. The formula is derived through the methods of matrix transformation. The qualitative regular expression was obtained by the analysis of three aspects.