Numerical multimode calibration technique for extraction of complex propagation constants of substrate integrated waveguide

Integrated planar technique has always been considered as a reliable candidate for low-cost mass production of millimeter-wave circuits and systems. In this paper, a numerical multimode calibration procedure is proposed and developed with a commercial software package on the basis of a full-ware finite element method (FEM) for the accurate extraction of complex propagation constants of substrate integrated waveguide (SIW). This SIW structures is a part of the substrate integrated circuits (SICs) family, which can largely preserve the advantages of normal rectangular waveguide. Two different lengths of the SIW are numerically simulated under multimode excitation. By means of the proposed technique, the complex propagation constant of each SIW mode can accurately be extracted. Experiments have verified the effectiveness of the proposed technique.