Antenna Array for Wireless Power Transfer to Deep-Brain Implants

Implantable medical devices, enabled by continually reducing the size of integrated circuits, offer therapeutic solutions to many intreatable disorders. Yet, the large battery size and short lifetime remain a major challenge. In this work, we present a microwave transmitting array (4×4) operating at 2.1 GHz that focuses propagating fields inside the brain tissue. This mode of transmission enables reaching deep in the brain. Analytical derivation of the efficiency is used to conjugate-match the phase of TX elements. A high power transfer efficiency of 0.91% is achieved when a 2×2 mm
²
implanted power receiver is located 5 cm away from the TX array.