Autofocus wireless power transfer to implantable devices in freely moving animals
A power transmitter is provided that can include a microwave cavity resonant at a desired operating frequency, a hexagonal mesh top to leak evanescent fields out of the cavity, and a plurality of orthogonal monopole feeds with 90 degrees phase differences creating circularly polarized waves. The power transmitter can be configured to transmit energy to a wireless device implanted in an animal passing through the evanescent fields. Implantable devices are also described which can receive wireless energy from the power transmitter and stimulate the animals (e.g., optogenetic or electrical stimulation).
1. A light delivery system, comprising:
a resonant cavity chamber configured to generate electromagnetic energy, the resonant cavity chamber comprising a surface lattice of subwavelength apertures upon which an animal can be placed; and
a wirelessly powered implantable device adapted to be implanted in the animal, the implantable device comprising:
a circuit board;
a power receiving coil coupled to the circuit board and adapted to receive electromagnetic energy from the resonant cavity;
a rectifier coupled to the circuit board and the power receiving coil and adapted to convert the electromagnetic energy received in the power receiving coil into a DC current;
a micro-LED coupled to the circuit board and adapted to provide optogenetic stimulation to the animal.
2. The light delivery system of claim 1 , wherein the implantable device is configured to be implanted on or adjacent to the animal's brain.
3. The light delivery system of claim 1 , wherein the implantable device is configured to be implanted on or adjacent to the animal's spinal cord.
4. The light delivery system of claim 1 , wherein the implantable device is configured to be implanted on or adjacent to nerve endings of one or more of the animal's limbs.
5. The light delivery system of claim 1 , further comprising a conductive extension coupling the micro-LED to the circuit board.
6. The light delivery system of claim 1 , wherein the implantable device has a volume ranging between 10 to 25 mm 3 .
7. The light delivery system of claim 1 , wherein the implantable device has a mass ranging from 20 to 50 mg.
8. The system of claim 1 further comprising a plurality of monopole feeds disposed in the resonant cavity chamber.
9. The system of claim 8 , wherein the a plurality of orthogonal monopole feeds are arranged with 90 degrees phase differences so as to create circularly polarized waves.