Understanding Equivalent Circuit Models

This section explains the topology of the RLGC circuit models produced by Q3D Extractor. It uses a combination of quasi-static field solvers to model interconnect structures. An electrostatic solver is used for capacitance (C), and a magneto-quasi-static solver for inductance (L) and resistance (R). The RLGC matrices are then combined into a circuit model to represent the overall behavior of the structure. Usually this quasi-static model is a good approximation to the structure's full-wave response up to a frequency corresponding to about ¼ wavelength.

When the dimensions of the RLGC matrices become large, these circuit models become very lengthy, making it difficult for users to untangle the basic topology of the equivalent circuits. While this is inevitable, it's also unfortunate, because the topologies are simple.