High-Q Slow-Wave Coplanar Transmission Lines on 0.35 μm CMOS Process

In this letter, experimental results and trends for shielded coplanar waveguide transmission lines (S-CPW) implemented in a 0.35 mu m CMOS technology are provided. Because of the introduction of floating strips below the CPW transmission line, high effective dielectric permittivity and quality factor are obtained. Three different geometries of S-CPW transmission lines are characterized. For the best geometry, the measured effective dielectric permittivity reaches 48, leading to a very high slow-wave factor and high miniaturization. In addition, measurements demonstrate a quality factor ranging from 20 to 40 between 10 and 40 GHz, demonstrating state-of-the-art results for transmission lines realized in a low-cost CMOS standard technology.