This letter reports a surface micromachined, complementary-metal-oxide-semiconductor compatible tunable capacitor utilizing a simply supported bridge structure, unlike traditional microelectromechanical-system bridges that use fully clamped boundary condition at the anchors. Through the implementation of a simply supported bridge driven by two 100-μm-long ZnO-actuated cantilevers, a compact tunable capacitor has been fabricated on silicon without any warping and shown to be capable of a 1400% continuous tuning from 0.13 to 1.82 pF. [ABSTRACT FROM AUTHOR]