Quasi-Analog Multi-Step Tuning of Laterally-Moving Capacitive Elements Integrated in 3D MEMS Transmission Lines
2011 (English)Conference paper (Refereed)
This paper reports on multi-position RF MEMS digitally tuneable capacitor concept resulting in quasi-analog tuning with large tuning range. The capacitors are integrated inside a coplanar transmission line whose tuning is achieved by moving the sidewalls of the 3D micromachined transmission line, with the actuators being completely embedded and shielded inside the ground layer. Devices with symmetrical two and three-stage actuators have been fabricated in an SOI RF MEMS process. A tuning range of Cmax/Cmin=2.41 with a total of 7 discrete tuning steps from 44 to 106 fF was achieved for the three-stage tuneable capacitors. Devices with actuator designs of different mechanical stiffness, resulting in actuation voltages of 16 to 73 V, were fabricated and evaluated. Therobustness of the actuator to high-power signals has been investigated by a nonlinear electromechanical model, which shows that self actuation occurs for high-stiffness designs (73 N/m) not below 50 dBm, and even very low-stiffness devices (9.5 N/m) do not self-actuate below 40 dBm.
Place, publisher, year, edition, pages
the European Microwave Association , 2011.
RF MEMS, tuneable capacitors, 3D micromachined transmission line
Other Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:kth:diva-47443OAI: oai:DiVA.org:kth-47443DiVA: diva2:455333
12th International Symposium on RF MEMS and RF Microsystems, Athens, June 27-29, 2011
QC 201111102011-11-102011-11-092011-11-10Bibliographically approved