Seamless Capacitive Body Channel Wireless Power Transmission Toward Freely Moving Multiple Animals in an Animal Cage.

Unstable wireless power transmission toward multiple living animals in an animal cage is one of the significant barriers to performing long-term and real-time neural monitoring in preclinical research. Here, seamless capacitive body channel (SCB) wireless power transmission (WPT) along with power management integrated circuit (PMIC) is designed using a standard 65 nm CMOS process. The SCB WPT enables stable wireless power transmission toward multiple 35 mm×20 mm×2 mm sized receivers (RXs) attached to freely moving animals in a 600 mm×600 mm×120 mm sized animal cage. By utilizing fringe-field capacitance and a body channel for wireless power link between the cage and RXs, the maximum difference in all measured power efficiencies in diverse scenarios is only 6.66 % with a 20 mW load. Even with a 90 RX rotation against the cage, power efficiency marks 17.76 %. Furthermore, an in-vivo experiment conducted with three untethered rats demonstrates the capability of continuous long-term power delivery in practical situations.