微带线无源互调的传输矩阵理论方法

Transfer matrix theory for Passive Intermodulation of microstrip lines

摘要:

均匀微带线是微带电路的基本结构，建立微带线PIM解析模型具有重要意义。本文基于受控源等效，在微带线的集总电路等效模型中，将微带线中的分布式寄生非线性PIM源建模为二次受控电流源或电压源，从而得到微带线PIM电压和电流关系的传输矩阵表达式，建立了寄生非线性机制的微带线PIM解析计算模型；并通过对比不同长度的镀镍微带线与不同浓度掺磷工艺镀镍微带线的传输互调与反射互调规律，验证本文提出的PIM传输矩阵方法的合理性。通过该模型提取了镍镀层在0.71 GHz时的三阶相对磁导率非线性系数为1×10^-10 m²/A²。本文方法为进一步建立其他复杂结构微带电路PIM模型提供了新思路。

Abstract:

The uniform microstrip line is the basic structure of the microstrip circuit, and it is of great significance to establish the Passive Intermodulation(PIM) analytical model of the microstrip line. Based on the controlled source equivalence, in the lumped circuit equivalent model of the microstrip line, the distributed parasitic nonlinear PIM source in the microstrip line is modeled as a second controlled current source or voltage source, to obtain the matrix expression of the relationship between the voltage and current in the stripline PIM. The analytical calculation model of the uniform microstrip line PIM with the parasitic nonlinear mechanism is finally established. The experimental verification is carried out by comparing the transmission intermodulation and reflection intermodulation laws of nickel-plated microstrip lines with different lengths and nickel-plated microstrip lines with different concentrations of phosphorus doping. The third-order relative permeability nonlinear coefficient of nickel coatings is extracted to be 1×10^-10 m2/A2 at 0.71 GHz. The proposed method based on controlled source equivalence provides a new idea for further establishing PIM models of other microstrip circuits.