Batteries Not Included: A Mat-Based Wireless Power Transfer System for Implantable Medical Devices As a Moving Target

Implantable devices have become increasingly popular in modern medicine. These devices have a wide range of applications, such as health monitoring, disease prevention, delivery of a therapeutic regimen, and biomimetic prosthesis. For example, electrical stimulation of nerve tissue and recording of neural electrical activity are the basis of emerging prostheses and treatments for spinal cord injury, stroke, sensory deficits, and neurological disorders [1]-[5]. Being able to record neural activity from awake animals with observable behavior has greatly advanced our understanding of the neural mechanisms that mediate behavior. Conventional microelectrode recording techniques typically require a percutaneous connector, which is associated with infection risks. Generally, in order to obtain stable recordings, animals must be trained to accept some degree of restraint (e.g., head fixation). Not only is the mobility of the animal subject limited, but the results obtained under such restricted conditions may not reflect the full repertoire of brain activity that occurs during natural behaviors [2]. This issue can be addressed with implantable electronics to record neural activity and wirelessly transmit this data through the skin to an external device. A wireless technique is then required to transmit both data and power, connecting the external system and the implanted devices.