端口复阻抗对滤波器特性影响分析

Influence of Port Complex Impedance on the Filter Performance

在传统的滤波器综合理论中,端口阻抗都假设为一个实阻抗.由于端口加载效应影响,实际的端口阻抗为一个复阻抗.端口复阻抗改变了滤波器的传输与反射相位特性,进而改变了滤波器的耦合矩阵元素.本文推导了端口复阻抗与实阻抗对应的耦合矩阵变换公式,并通过电路软件进行建模仿真,仿真结果与理论吻合良好,验证了理论的正确性.

In the traditional filter synthesis theory, the port impedance is assumed to be a real impedance. Due to the influence of the port loading effect, the actual port impedance is a complex impedance. Port complex imped-ance changes the transmission and reflection phase characteristics of the filter and then changes the coupling matrix elements of the filter. 1n this paper, the coupling matrix transformation formula is derived and the simulation results are in good agreement with the theory which verifies the correctness of the theory.