Wideband Mechanical Excitation by a Microcorona-Driven Vibrating Element

We have designed, fabricated, and tested a microcorona driven (MCD) vibrating element. The vibrating element consists of a mass plate at the end of a cantilever. The proof mass is selectively driven by either one or two microcorona ionizers. During the dc negative corona discharge, the build-up of negative space charge electrostatically repelled the cathodes on the mass plate against the mechanical elastic force of the spring, damping force, and electrostatic force. This resulted in the wideband mechanical self-excitation of the MCD vibrating element. Using laser Doppler vibrometry (LDV), two resonance frequencies of out-of-plane modes were measured experimentally at peak values of 896 and 1312 Hz, and it was consistent with the ANSYS finite element modal analysis results at ~823 and 1323 Hz, respectively. The transition from Trichel pulse mode to diffuse glow mode resulted in a discontinuity in the experimental plot of proof mass velocity versus applied voltage. The MCD vibrating element consumed a maximum power of ~100 mW and had a maximum resultant driving force of ~0.45 μN in the first observed driving mode. The maximum out-of-plane oscillation amplitude measured was to be ~2 μm.