In this work we explored an alternative approach to mechanical oscillator design: the dual-mass oscillator. A two-degree-of-freedom system forced at antiresonance can attain larger vibration amplitudes at a given drive voltge with parallel-plate actuation than with comb drive actuation. Amplitudes of 0.85 μm in air at atmospheric pressure were observed with supply voltage under 5V. Amplitudes at resonance and antiresonance were measured. The parallel plate structure exhibited instability at low drive voltages because of the nonlinear drive. Structures with stiffer springs will solve this problem. An expression for the electrostatic force vs. displacement was developed using finite element methods. When this expression was used in simulations, the absorber mass steady-state amplitude closely matched measurements. Finite element analysis was done on the dual-mass oscillator. The natural frequencies of the out-of-plane modes were close to the in-plane modes and could potentially cause problems, depending on the magnitude of the out-of-plane force.

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