High-Q micromechanical resonators and filters for ultra high frequency applications

Abstract

Recent progresses in Radio Frequency Micro Electro Mechanical Sensors (RF MEMS) area have shown promising results to replace the off-chip High-Q macroscopic mechanical components that are widely used in the communication technology. Vibrating micromechanical silicon resonators have already shown quality factors (Q) over 10,000 at radio frequencies. Micromechanical filters and oscillators have been fabricated based on the high-Q micro-resonator blocks. Their fabrication processes are compatible with CMOS technology. Therefore, producing fully monolithic transceivers can be possible by fabricating the micromechanical components on the integrated circuits. In this work, we examine the general characteristics of micromechanical resonators and propose a novel low loss resonator type and a promising filter prototype. High frequency micromechanical components suffer from the anchor loss which limit the quality factor of these devices. We have developed a novel technique to reduce the anchor loss in extensional mode resonators. Fabrication processes of the suggested structures are relatively easy with respect to the current high-Q equivalents. The anchor loss reduction technique does not introduce extra complexities to be implemented in the existing structures.