Electromagnetic simulation was found to show promise as a method to measure the properties of a thin film with an interdigital capacitor (IDC) constructed on it. Given a film permittivity as measured by the split-cavity resonator technique, IDC simulations were adjusted until the simulated results approached those measured from the physical sample. The difference between the measured and simulated capacitance was reduced to about 5% over the frequency range of interest. With the knowledge of the effects of different simulation parameters, the properties of the simulated film can be adjusted until the simulation results match the measured results, and the properties of the measured film can be inferred to match the design parameters of the simulated film. The method is a general technique that may be applied to microwave dielectric characterization of thin films, thick films and bulk ceramics, and it is particularly useful for submicron films with high permittivity.