Abstract
An iterative method based on the concept of a wave using a fast Fourier transformation on the waveguide environment (modal fast Fourier transformation: MFFT) for the investigation of a coplanar spiral inductor is presented. This method is used to calculate S-parameters of shielded microwave components including air bridges. The general formulation and the implementation procedure of the method are described. The application of the theory is verified by a comparison of experimental data.