High-Q micromechanical oscillators and filters for communications

With Q´s in the tens to hundreds of thousands, micromachined vibrating resonators are proposed as IC-compatible tanks for use in the low phase noise oscillators and highly selective filters of communications systems. To date, LF oscillators have been fully integrated using merged CMOS+microstructure technologies, and bandpass filters consisting of coupled resonators have been demonstrated in the HF range. The performance of fabricated two- and three-resonator filters with center frequencies ranging from 300 kHz to 10 MHz and filter Q´s from 100 to 2400 are reported. Evidence suggests that the ultimate frequency range of this high-Q tank technology depends upon material limitations, as well as design constraints-in particular, to the degree of electromechanical coupling achievable in micro-scale resonators