We report on the design, fabrication, and measurement of anovel MEMS (MicroElectroMechanical System) tunablecapacitor with angular vertical comb-drive (AVC) actuators. TheAVC allows continuous rotation and therefore large tuning ratiowithout pull-in. The device fabrication process is relativelysimple, consisting of a single deep reactive ion etching stepfollowed by release and out-of-plane assembly of the angularcombs. We also report a new 3-D self-assembly process usingreflowed Dow Chemical’s BCB (Cyclotene) hinges, which aremore robust than conventional photoresist hinges. The use ofglass substrate has greatly reduced parasitic capacitances. Atuning ratio of 4.2 has been achieved with 10-μm-thick devicelayer. Our theoretical simulation shows that larger tuning ratiocan be achieved with thicker device layers and furtheroptimization of the design.
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