Microstrip circuits on micromachined silicon

Fully monolithic integration of a millimeter wave system on silicon requires low loss passive circuitry. Transmission line elements are needed to interconnect active devices and to realize distributed passive components. Using bulk micromachining and high resistivity silicon on insulator (SOI) wafers, well defined thin silicon membranes can be manufactured. This allows the use of microstrip circuits on silicon substrates at frequencies beyond 100 GHz. Full wave simulation results accompanied by measurements are presented for coplanar to microstrip transitions, microstrip lines and two simple test circuits.