Novel micromachined approaches to MMICs using low-parasitic, high-performance transmission media and environments

A new micromachined technology suitable for three-dimensional planar circuit configurations has been presented. At higher frequencies, problems associated with the substrates make conventional approaches unfeasible, and membrane supported circuit components offer the only planar alternative to costly waveguide-based approaches. Micromachined transmission lines and circuits have been shown to perform very well in frequency bands all the way up to W-band (110 GHz). Circuits commonly used in CPW implementations are shown to have superior performance when realized with membrane supported transmission lines like the microshield line. The microshield line has a relative effective dielectric constant of 1.07 through 100 GHz and, as a result, it exhibits zero dispersion and zero substrate loss. The micromachined CPW has the lowest attenuation yet demonstrated for planar transmission lines. Filters and resonant stubs have been measured up to 250 GHz and have demonstrated an unparalleled electrical performance.