| In this thesis research, I have developed and used numerical techniques to study and model the propagation characteristics of coplanar waveguides (CPWs) over a broad frequency range, from about 10 GHz to nearly 1 THz. This research is important as CPWs gain broader applications in integrated circuits (ICs), both as interconnects and as passive circuit-elements. My research is also timely because experimentally measured waveguide properties have become available in recent years that allow comparison with theoretical studies.;Two types of CPWs were investigated. The first type uses wide ground lines (WG) and closely approximates an ideal waveguide, which contains semi-infinite substrate thickness and ground-plane widths and has been analytically studied using conformal mapping. These WG CPWs are thus important as a testing venue where our numerically modeled waveguide characteristics are compared with both experiments and closed-form analysis.;The second type of CPWs uses narrow ground lines (NG) and is the practical choice in IC applications that have severe "real estate limitation," i.e. where minimal chip area can be assigned to passive circuit components such as interconnects. These waveguides have, until this work, only been qualitatively studied. In this thesis, their properties will be thoroughly investigated and modeled.;In one particular group of waveguides, made on a GaAs substrate, my work is compared with experiments for both the WG and NG waveguides. The close comparison lends strong support to the validity of my approach. The modeling is then extended to the practically important waveguides made on a silicon substrate. I will detail how parameters such as waveguide ground-plane widths and lateral line dimensions change the high-frequency characteristics and how they can be designed to improve circuit performance. Finally, some directions for future studies are discussed. |
