Digitally-specified micromechanical displacement amplifiers

Abstract

A micromechanical displacement amplifier comprising two asymmetric resonator array composites coupled by a quarter-wavelength beam has been demonstrated that permits specification of gain factor by mere (digital) selection of an appropriate ratio of the number of resonators in an input array to that in an output array. Like the method of [1], this displacement gain circuit is a key enabler for resoswitch-based mechanical power amplifiers and power converters, because it can prevent unwanted drive electrode-to-resonator impact in such circuits. This design, however, differs from that of [1] in that 1) it can be applied to radial-contour mode disks that can achieve much higher frequency than the wine-glass disks of [1]; 2) it preserves the frequency and Q of its constituent resonators (whereas the method of [1] changed the frequency and lowered the Q); and 3) its digital method for gain specification is much more straightforward, accurate, and repeatable.

A metal micromechanical resonant switch for on-chip power applications

“…Defensive design to prevent pull-in should be possible in future renditions of this device. For example, instead of creating different disk-to-electrode gaps at input and output, the displacement amplifier designs described in [7] and [8] employing mechanical stiffness engineering to generate larger displacements at the output disk than the input, can prevent input impacting in a more repeatable and effective way. Furthermore, removing electrode overhangs via the etch-back process introduced in [15] increases the dc pull-in voltage, thereby helping to stabilize the device during switching.…”

“…This sputtering step is surprisingly conformal over the sides of the disks, but fortuitously, not completely isotropic. In particular, proper orientation of the wafer in the sputtering chamber permitted deposition of different thicknesses along the different axes of the disk, allowing this process to realize the unequal input and switch axis electrode-to-resonator gaps needed for proper switch operation [7] [8]. After the gap-defining deposition, anchors for the electrodes are patterned and etched into the total TiW layer, and electrodes surrounding the disk are electroplated through a 2 nd photoresist mold to yield Fig.…”

Electro-mechanically induced GHz rate optical frequency modulation in silicon

“…The modulator presented in [21] is extended to an array of mechanically coupled ring resonators for large electrostatic driving force. We also use a mechanical lever system [22] to realize displacement amplification. An array composite of rings on the input electrostatic side feeds via an acoustic quarter-wavelength coupling beam into a single output opto-mechanical ring resonator, as illustrated in Figure 2.a.…”

Partial Gap Transduced MEMS Optoacoustic Oscillator Beyond Gigahertz

“…This paper explores and demonstrates two innovations to the coupled-ring resonator based opto-acoustic oscillator (OAO) design to target higher frequencies. The first innovation is to use a micro-mechanical displacement amplifier [18] to achieve larger optical modulation. The second innovation is to use partial air gap capacitive transduction to enhance the electromechanical transduction efficiency at higher frequencies.…”