RIGOROUS ANALYSIS OF MODE PROPAGATION AND FIELD SCATTERING IN SILICON-BASED COPLANAR MIS SLOW-WAVE STRUCTURES WITH ABRUPT TRANSITIONS TO TRANSMISSION-LINES ON NORMAL SUBSTRATE

This paper presents a rigorous field theoretical analysis of slow wave mode propagation in coplanar waveguide (CPW) metal-insulator-semicond uctor (MIS) transmission lines with a laterally confined doping profil e, Two types of transmission line structures are investigated - hulk s ilicon and semiconductor-on-insulator (SOI), In both cases a Gaussian profile of the doping depth is assumed, It was found that an optimum l ateral width of the doping region exists for which both structures exh ibit a much better slow wave factor at lower losses than traditional t hin-film MIS transmission lines, The abrupt transition between MIS, CP W, and CPW on a normal insulating substrate was investigated as well. It was found that the reflection coefficient increases significantly w ith frequency and when the lateral width of the doping region is exten ded over the whole cross section of the CPW, The investigation was car ried out using the frequency-domain transmission line modeling (TLM) ( FDTLM) method.