Wireless power link design using silicon-embedded inductors for brain-machine interface

This paper discusses the safety requirements, equivalent circuit model, and design strategy of wireless power transmission to neural implants. The most daunting challenge is the design of the integrated receiving coil on the implantable device whose size must be within the safety and regulation limits while providing sufficient power transfer and efficiency. A novel silicon substrate-embedded 3.6-H spiral inductor has been designed to fit inside a 4.5 mm 4.5 mm implantable IC as the receiving coil. Full-wave EM simulations show that in a practical brain-machine interface setting, wireless power in the range of 1-10 mW can be delivered at 5% efficiency to an implant at 1 cm below the head surface using signals between 2 to 5 MHz. To achieve a high transfer efficiency, the optimal impedance for loading the receiving coil is derived using the equivalent circuit parameters of a realistic 3D model of the entire wireless power link. The large parasitic capacitance of the in-chip inductor is methodically absorbed in the matching network to maximize the efficiency and power transfer. © 2012 IEEE

Wireless Power Transfer For Biomedical Applications

In this research wireless power transfer using near-field inductive coupling is studied and investigated. The focus is on delivering power to implantable biomedical devices. The objective of this research is to optimize the size and performance of the implanted wireless biomedical sensors by: (1) proposing a hybrid multiband communication system for implantable devices that combines wireless communication link and power transfer, and (2) optimizing the wireless power delivery system. Wireless data and power links are necessary for many implanted biomedical devices such as biosensors, neural recording and stimulation devices, and drug delivery and monitoring systems. The contributions from this research work are summarized as follows: 1. Development of a combination of inductive power transfer and antenna system. 2. Design and optimization of novel microstrip antenna that may resonate at different ultra-high frequency bands including 415 MHz, 905 MHz, and 1300MHz. These antennas may be used to transfer power through radiation or send/receive data. 3. Design of high-frequency coil (13.56 MHz) to transfer power and optimization of the parameters for best efficiency. 4. Study of the performance of the hybrid antenna/coil system at various depths inside a body tissue model. 5. Minimizing the coupling effect between the coil and the antenna through addressed by optimizing their dimensions. 6. Study of the effects of lateral and angular misalignment on a hybrid compact system consisting of coil and antenna, as well as design and optimize the coilâs geometry which can provide maximum power efficiency under misalignment conditions. 7. Address the effects of receiver bending of a hybrid power transfer and communication system on the communication link budget and the transmitted power. 8. Study the wireless power transfer safety and security systems