Micromachining technologies for miniaturized communication devices

An overview of the key micromachining technologies that enable communications applications for MEMS is presented with a focus on frequency-selective devices. In particular, micromechanical filters are briefly reviewed and key technologies needed to extend their frequencies into the high VHF and UHF ranges are anticipated. Series resistance in interconnect or structural materials is shown to be a common concern for virtually all RF MEMS components, from mechanical vibrating beams, to high-Q inductors and tunable capacitors, to switches and antennas. Environmental parasites—such as feedthrough capacitance, eddy currents, and molecular contaminants—are identified as major performance limiters for RF MEMS. Strategies for eliminating them via combinations of monolithic integration and encapsulation packaging are described.