A new approach for the design of low velocity coupling for ring shape anchored contour mode disk resonators

The design of RF MEMS filters is a very important research area in the RF MEMS resonator field especially for UHF frequencies. Having very high Q and compatibility with the state-of-the-art CMOS technology, RF MEMS resonators could construct channel select filters in RF transceivers front-end and surmount the need for IF stages by direct conversion. But, there is a problem for coupling of high stiff contour mode disk resonators, because there is no nodal region at the perimeter of this kind of resonators for establishing the low velocity coupling without applying asymmetry on the resonance performance of the resonators. This paper introduces a pioneering technique for low velocity coupling of these resonators without any asymmetry. Analytical design approach and FEM analysis are provided in this paper and our discussions are verified by various simulations. The resulting filter could be designed to obtain 0.004 % of bandwidth with reasonable sizes which is completely enough for channel selection in low GSM standard.