Micromechanical active amplifiers using the mechanical resonance modulated by variable stiffness springs

We present micromechanical active amplifiers using carrier motion in the mechanical resonance, thereby performing the amplification of displacement, force, and energy. The carrier motion is modulated by variable stiffness springs whose stiffness change is proportional to input motion. We design, fabricate, and test two types of the amplifiers A and B, including two different variable stiffness springs A and B, which are designed to increase output stiffness variation and output-to-input stiffness ratio, respectively. The displacement gain of amplifier A is 5.62, which is 2.15 times larger than that of the amplifier B. The force gain of the amplifier B is 10.0, which is 1.26 times larger than that of the amplifier A. We experimentally verify that the present devices are able to amplify both displacement and force simultaneously, showing potential applications of high-sensitive sensing and high-force/long-range actuation.