Reducing anchor loss in micromechanical resonators using phononic crystal strips

In micromechanical resonators, energy loss via the anchors into the substrates may lead to a low quality factor. To eliminate the ill effect of anchor loss, in this paper a phononic band-gap structure is employed. We demonstrate a design of phononic-crystal (PnC) strips used to support extensional wine-glass mode ring resonators to increase the quality factors. PnC strips are introduced here to stop elastic wave propagation by the band-gap or deaf-band effects. Numerical analyses of resonant characteristics of the ring resonators and the dispersion relations, eigenmodes, and transmission properties of the PnC strips are presented. With the proposed resonator architecture, the finite-element simulations show that the leaky power is effectively reduced and the stored energy inside the resonators is enhanced simultaneously as the operating frequencies of the resonators are within the band gap or deaf bands. Realization of a high quality-factor micromechanical ring resonator with minimized support loss is expected.