High-Reliability RF-MEMS Switched Capacitors With Digital and Analog Tuning Characteristics

This paper presents an RF microelectromechanical system switched-capacitor suitable for tunable filters and reconfigurable networks. The switched-capacitor results in a digital capacitance ratio of 5 and an analog capacitance ratio of 5-9. The analog tuning of the down-state capacitance is enhanced by a positive vertical stress gradient in the the beam, making it ideal for applications that require precision tuning. A thick electroplated beam (4-4.5 μm) results in Q greater than 100 at C-X-band frequencies, switching times of 30-50 μs, and power handling of 0.6-1.1 W. The design also minimizes charging in the dielectric, resulting in excellent reliability performance even under hot-switched and high-power (1 W) conditions.