Frequency-Dependent Substrate Characterization via an Iterative Pole Search Algorithm

The characterization of frequency-dependent material properties is an important issue in nowadays high-speed interconnect design. This letter presents a practical method to determine the complex permittivity of a substrate material, by combining measurements with simulations. A rational permittivity model is determined by searching for its poles and residues using an iterative optimization method. Its accuracy is verified by comparing coplanar waveguide measurements with simulations based on the new material model.