Electrostatic fringing-field actuation for pull-in free RF-MEMS analogue tunable resonators

J. Small, University of California Davis
W. Irshad, Birck Nanotechnology Center, Purdue University
Adam Fruehling, Birck Nanotechnology Center, Purdue University
A. Garg, Birck Nanotechnology Center, Purdue University
X. Liu, University of California Davis
Dimitrios Peroulis, Birck Nanotechnology Center, Purdue University

Abstract

This paper presents the design, fabrication and measurement of the first pull-in free tunable evanescent-mode microwave resonator based on arrays of electrostatically actuated fringing-field RF-MEMS tuners. Electrostatic fringing-field actuation (EFFA) is the key on achieving a wide tunable frequency range that is not limited by the conventional pull-in instability. Furthermore, total lack of dielectric layers and no overlap between the pull-down electrode and movable beams significantly enhance the robustness of our proposed tuning mechanism by making it devoid of dielectric charging and stiction and amenable to high-yield manufacturing. The proposed electrostatic fringing-field tuners are demonstrated in a highly loaded evanescent-mode cavity-based resonator. The measured unloaded quality factor is 280-515 from 12.5 to 15.5 GHz. In addition, a 10x improvement in switching time is demonstrated for the first time for EFFA tuners in a tunable microwave component by employing dc-dynamic biasing waveforms. With dynamic biasing, the measured up-to-down and down-to-up switching times of the resonator are 190 and 148 mu s, respectively. On the other hand, conventional step biasing results in switching times of 5.2 and 8 ms for up-to-down and down-to-up states, respectively.

Discipline(s)

Nanoscience and Nanotechnology