Miniaturized Wireless Power Transfer Module Design for Brain Optoelectronic Implant

Optogenetics is a clinical methodology that stimulates genetically modified neurons in the brain using Lasers or μLEDs. The most challenging part of designing an optoelectronic implant is to deliver continuous power to the μLED. To overcome this challenge, a wireless power transfer module is designed and presented in this paper. A miniaturized 10.5 mm×10.5 mm receiver coil has been designed and fabricated using the FR4 substrate and Cu trace as a prototype. Inductive power transmission with magnetic coupling has been utilized to transfer power to the implant at a frequency of 7.2 MHz. The measurement data of the resonant coil shows a return loss (S
₁₁
) of -9.08 dB, a received power of -15.48 dBm in the air and -18.58 dBm in the muscle media at 5 mm distance with 0 dBm input power. With the design of the proper matching network, the achieved efficiency can be further improved.