Efficient capacitive transduction of high-frequency micromechanical resonators by intrinsic cancellation of parasitic feedthrough capacitances

Parasitic feedthrough capacitances represent a generic issue for capacitively transduced microelectromechanical resonators. Those parasitic capacitances degrade the output signal’s magnitude and phase by increasing the feedthrough signal and attenuating the resonance peak because of the resulting antiresonance peak. Whereas classical capacitive actuation/detection schemes only partially circumvent this issue, this work presents a specific, balanced, set-up that intrinsically cancels the effects of feedthrough capacitances. The resonator can recover its intrinsic purely RLC behavior thanks to this method which preferentially applies to given bulk modes, such as Lame for plates and elliptic for disks. It has been experimentally tested on 100 MHz plates and disks.