Development of released micromachined structures for millimeterwave device applications: preliminary results

The exploding interest in miniaturized subsystems for mobile and satellite communications applications has revealed a dire need for higher levels of integration, performance, and cost-effectiveness from millimeter-wave components. Monolithic microwave integrated circuit (MMIC) technology has enabled tremendous strides in efforts to miniaturize analog communications circuits and deliver advanced performance at the higher, less-crowded millimeter-wave frequency regime. Similarly, microelectromechanical systems (MEMS) technologies have realized their own successes in the likes of accelerometers for air-bag deployment systems and miniaturized motors. The strengths of MMICs and MEMS, two areas whose applications have largely developed independently, can now be synthesized to yield the types of components that will deliver the high performance, space efficiency, and low cost demanded by the current communications technology needs. This paper reports preliminary progress in the development of released surface-micromachined structures suitable for use in such millimeter-wave device applications. Several experimental structures are described, with a brief overview of the fabrication process used and the eventual millimeter-wave circuit context for the structures.