Analysis of slow-wave phenomena in coplanar waveguide on a semiconductor substrate

A method of analyzing the coplanar waveguides on insulator-semiconductor substrates to satisfactory accuracy is presented. A standard MIS coplanar line has its insulator removed and replaced by a Schottky contact along the center strip and ohmic contacts at the ground planes, and the structure is modeled with a waveguide geometry and analyzed using a mode-matching technique. The electric and magnetic vector potentials are defined, the field expressions found, and the potentials expanded in terms of proper eigenfunctions. Convergence of the solution was tested using several lossless models, and no more than two eigenfunctions were necessary in one region to obtain accurate values of propagation constants with less than one percent error. More eigenfunctions were needed in other regions. MIS structure tests showed somewhat slower convergence.