RF-MEMS Tunable Capacitor With 3 V Operation Using Folded Beam Piezoelectric Bimorph Actuator

Tunable capacitors with high tuning range and high Q-factors are indispensable for realizing reconfigurable radio-frequency (RF) circuits for multiband/multimode next-generation mobile wireless communication terminals. A novel RF microelectromechanical systems tunable capacitor having a piezoelectric bimorph actuator has been developed using a complementary metal-oxide-semiconductor compatible surface micromachining process. Folded beam piezoelectric actuators were introduced to cancel curling of the actuator beam due to residual stress. The continuous wide tuning ratio of three was realized at an operation voltage of less than 3 V for the first time