Passive integration and RF MEMS: a toolkit for adaptive LC circuits

RF MEMS variable capacitors have been realized in an industrialized thin-film process for manufacturing high-quality inductors and capacitors on high-ohmic silicon. The fixed as well as the moveable electrode consists of aluminium, the native aluminium oxide is used as a dielectric. A tuning ratio of 1.35 and a switching ratio up to 29 have been measured. At RF frequencies they show low ohmic losses, which make them very suitable for use in high-quality adaptive LC networks. The feasibility of the application of switched capacitors for load switching in GSM power amplifiers has been demonstrated through simulations based on experimentally derived components and systems parameters.