Design and Fabrication of an Annular High Frequency Resonator

We present a new high frequency resonator using a high order mode shape of an annular structure. The basic concept of an annular high frequency resonator (AHFR) is presented and the AHFR is fabricated by using a standard surface micromachining technology. Using theoretical analysis, the resonant frequency of the AHFR was expressed in a simple form. On this basis, a theoretical formula for the AHFR has been developed in terms of the structure’s geometry and material properties. The outer diameters of the 3.5μm-thick polysilicon AHFR with resonant frequencies of 100MHz, 500MHz and 1GHz are 192μm, 96μm and 61μm, respectively. This results in areas sufficient large to readily sense the filtered signal. Fundamental characteristics of the mode shape and resonant frequency of the AHFR have been discussed.