Embedded thin film model in finite difference time domain method

A thin film model is embedded into the finite difference time domain (FDTD) method to solve the multi-scale problem effectively in the existence of thin carbon fiber composite (CFC) panels in the computational electromagnetics. In this model, the thin film works as a section of transmission line and can be replaced by its admittance matrix in the frequency domain. The digital filter theory and inverse Z transform are used to transform the frequency domain admittance matrix into its time domain form, which could be incorporated into the FDTD method. The embedded model has the advantages of saving computational resources due to the fact that it does not discretize the thin film and relatively large mesh size can be used in the surroundings. In this paper, the embedded model is used to analyze the reflection and transmission performance of a single-layered CFC panel. The results are compared with those from analytical solutions, which validates its accuracy, convergence and effectiveness. In the end, the embedded model is applied to analyze the effects of the electrical parameters of the CFC panel on its shielding performance.