An NFC (near-field communication) based wireless power transfer system design with miniaturized receiver coil for optogenetic implants

Optogenetics is the control and monitoring of genetically modified neurons that are responsive to light. It has opened the door for neuroscience research by providing a means to understand the neural circuit dysfunctions such as mood disorders, addiction, and Parkinson's disease. With the growing demand for biomedical implants, the need for a wireless power transfer (WPT) module is also increasing. An essential part of optogenetic implants is the power source of the device. A wireless optogenetic implant requires enough voltage and current to power an LED to stimulate the neurons. In this paper, a WPT module with a transmitter and a compact receiver module are presented. The receiver module contains a miniaturized 6 × 6 mm2 receiver antenna, a Schottky diode, and a mini-LED. The proposed WPT scheme utilizes near-field communication and inductive power transmission at 7.15 MHz frequency. Simulation results using High Frequency Structure Simulator (HFSS) show that the receiver antenna achieves up to a −15.37 dB return loss (Sii) at the resonating frequency. The fabricated WPT system transfers 500 mVpp to the receiver module at 5 mm distance for an input power of 0 dBm. The received power is rectified to provide an average 200 mV DC to turn on a mini-LED. The preliminary simulation and measurement results of the proposed WPT module show a better prospect for future optogenetics based applications.