A fast numerical modeling approach based on network characteristic mode analysis (CMA) is presented and investigated for analyzing electrical layouts in miniature RF filters, such as surface acoustic wave filters. In this approach, a generalized eigenvalue decomposition is performed on the Z-parameters of an electrical layout at one or two sampling frequencies that can be computed and extracted with any numerical full-wave method. The obtained eigenvalues are used to extract modal resistance, inductance, and capacitance matrices for each eigenmode. The frequency dependence of the modal resistance matrix can be assumed a priori or determined automatically, and the modal inductance and capacitance matrices are assumed frequency independent. These modal matrices are then used to approximate the Z-parameters at any other frequencies to provide the response of the electrical layout, which can then be combined with the frequency responses of other components, such as resonators, to yield the electrical response of an entire RF filter. Compared with the previously developed analytic extension of eigenvalues, this fast CMA-based method is less affected by the frequency variation of eigenmodes since the frequency dependences of the eigenmodes are implicitly canceled out in its formulation. The accuracy of this approach is evaluated by comparing with results from full-wave analyses. For RF circuits whose electrical sizes are small and whose frequency range of interest is relatively small, the proposed CMA-based fast frequency sweep approach is found to be sufficiently accurate and highly practical for engineering applications.

中文翻译：

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使用网络特性模式分析加速射频电路的数值建模

提出并研究了一种基于网络特性模式分析 (CMA) 的快速数值建模方法，用于分析微型 RF 滤波器（如表面声波滤波器）中的电气布局。在这种方法中，在一个或两个采样频率下对电气布局的Z参数执行广义特征值分解，可以使用任何数值全波方法计算和提取这些频率。获得的特征值用于提取每个特征模式的模态电阻、电感和电容矩阵。模态电阻矩阵的频率相关性可以假定为先验或自动确定，并且模态电感和电容矩阵假定为与频率无关。然后使用这些模态矩阵来近似Z- 任何其他频率下的参数以提供电气布局的响应，然后可以将其与其他组件（例如谐振器）的频率响应组合，以产生整个 RF 滤波器的电气响应。与先前开发的特征值解析扩展相比，这种基于 CMA 的快速方法受特征模态频率变化的影响较小，因为特征模态的频率依赖性在其公式中被隐式抵消。通过与全波分析的结果进行比较来评估这种方法的准确性。对于电气尺寸较小且感兴趣的频率范围相对较小的 RF 电路，发现所提出的基于 CMA 的快速扫频方法对于工程应用而言足够准确且具有高度实用性。