Numerical Multimode Thru-Line (TL) Calibration Technique for Substrate Integrated Waveguide Circuits

In this work, the conventional numerical thru-line (TL) calibration technique is generalized to extract the network parameters of a discontinuity in a frequency range in which higher order modes can propagate. The generalization is achieved by a new matrix formulation based on an efficient decomposition of the involved matrices into submatrices. First, a full-wave solver is used to determine the scattering parameters of a discontinuity with respect to reference plane on a standard waveguide such as the rectangular waveguide. Then, by applying the proposed multimode TL calibration, the generalized scattering parameters of the discontinuity are obtained with respect to the reference planes chosen on the connecting guide e.g., substrate integrated waveguide. As will be shown, the method greatly saves computation time in an analysis of cascaded discontinuities.