Broadband Circuit Model for Electromagnetic-Interference Analysis in Metallic Enclosures

The electrical behavior of a cavity with arbitrary shape, lossy walls, and lossy filling material, which is excited by electrically small current probes, is represented by a novel broadband Foster-type circuit based on the eigenmodes of the cavity. This model is inherently stable in the time domain and allows the inclusion of arbitrary nonlinear loads with a commercial circuit simulator. The convergence of the circuit model is accelerated by the extraction of quasi-static inductances and capacitances. The presented model is validated in the frequency and time domain by elaborate full-wave simulations. An application example is presented concerning a basic computer-casing setup.