Reconfigurable MEMS latching-type capacitors for high power applications

Abstract

This paper reports the design and characterization of two reconfigurable MEMS discrete capacitor banks for high power and low frequency applications. The first design is a 3-bit capacitor bank built using three parallel-connected series-switched comb-drive capacitors with appropriately scaled values. The second design is a compact discretized comb-drive varactor that can be operated as 2-bit or 3-bit capacitor bank depending on the number of latched states. Both devices are demonstrated using the METALMUMP process where 20 µm-thick plated nickel is the only structural and metal layer. The MEMS switches use thermal actuation with chevron actuator design. This allows for large displacements at relatively low actuation voltages. Using mechanical latching for both designs, the switch reconfiguration energy is minimized. The relatively very high mechanical stiffness inherent to both thermal actuator designs provides an excellent immunity to self-actuation at high RF power levels. The proposed MEMS switches are capable of operating under low-pressure conditions (e.g. in a package), without degradation of their thermo-mechanical performance.

RF MEMS electrostatically actuated tunable capacitors and their applications: a review

“…The MEMS capacitors are tuned by deflecting thin gold metal layers on dielectric layer, thus increases the capacitance 3 times to the initial capacitance, from 25 fF to 75 fF. Several high power tunable capacitor banks are reported in [87][88][89]. These high power capacitors are essential for impedance tuning of high power transmitters at the base station of mobile industries and satellite communications.…”

An efficient electro‐thermo‐mechanical model for the analysis of V‐shaped thermal actuator connected with driven structures

“…Similarly, mechanical test platforms for various materials are built by taking advantage of V‐shaped actuators 4,6‐8 . RF MEMS switches driven by V‐shaped thermal actuator were designed in Reference 9 and these designs showed the capability to work at high RF power levels. In Reference 10, V‐shaped actuator was used to tune the resonant frequency.…”