Wireless Power Transfer

Micro-scale wireless charging device as an implantable neuromodulator or a wireless actuator

In 1914, Nikola Tesla was awarded a patent that described wireless power transfer (Apparatus for wireless transmission of electrical energy, US Patent 1,119,732). Over a century later, the promise of wireless power transfer is yet to be widely realized. This is in spite of numerous potential applications, ranging from remote operation of consumer electronics, implanted biomedical devices and sensors, and actuation of devices for which hard-wired power sources are neither desirable nor practical. In particular, biomedical devices implanted in the body or the brain require small footprint power receiving elements for wireless charging, which can be accomplished by micromechanical resonators. We have demonstrated successful actuation of micron-sized silicon-based piezoelectric resonators at power levels of nanowatts and distances of about three feet.

Featured

Wireless Micromachines

An antenna design that taps into electric fields across air gaps makes low-power, wireless biomedical implants more feasible. Micromechanical resonators are tiny, silicon-based cantilevers that, due to their sensitivity to high-frequency AC fields, are being targeted as the receiving elements in wireless power designs.

Micromechanical Resonator Driven by Radiation Pressure Force

Radiation pressure exerted by light on any surface is the pressure generated by the momentum of impinging photons. The associated force – fundamentally, a quantum mechanical aspect of light – is usually too small to be useful, except in large-scale problems in astronomy and astrodynamics.

Wireless Actuation of Bulk Acoustic Modes (BAW) in Micromechanical Resonators

We report wireless actuation of a Lamb wave micromechanical resonator from a distance of over 1 m with an efficiency of over 15%.

Wireless transfer of power by a 35-GHz metamaterial split-ring resonator rectenna

Wireless transfer of power via high frequency microwave radiation using a miniature split ring resonator rectenna is reported. The near-field behavior of the rectenna is investigated with microwave radiation in the frequency range between 20-40 GHz with a maximum power level of 17 dBm.

Micromechanical microphone using sideband modulation of nonlinear resonators

The first microphone was invented and patented by Emile Berliner in the late nineteenth century. Since then, microphone diaphragm sizes have shrunken to as- tounding sizes and continue to shrink.

Optical wireless information transfer with nonlinear micromechanical resonators.

Wireless transfer of information is the basis of modern communication. It includes cellular, WiFi, Bluetooth, and GPS systems, all of which use electromagnetic radio waves with frequencies ranging from typically 100 MHz to a few GHz.