A 116.4 mg Wireless Ultra-Lightweight Microstimulator for Cyborg Bees

Abstract

Cyborg insects are considered to be viable substitutes for micro air vehicles (MAVs) with the wireless electric microstimulator. The design of a wireless stimulator with lightweight, small-size, and low-power that can be comfortably carried by insects in free motion has proved critically challenging. Here, a novel wireless microstimulator with an ultra-lightweight of 116.4 mg and a compact size of 121.8 mm${}^{\rm 3}$ is reported. It combines semiactive radio frequency identification (RFID) technology and millimeter-scale miniaturized antenna with heterogeneous integration process, thus meeting the stringent requirements of cyborg bees. The semiactive RFID technique uses radio-frequency energy harvesting to supply the power of wireless communication and then greatly reduce the energy requirement of the battery. To satisfy the radio-frequency energy harvesting requirement and realize conjugate matching of semiactive RFID chip and antenna at the same time, a millimeter-scale miniaturized antenna with compact spiral-structure is designed. A high-flexible heterogeneous integration process that combines the MCU die, antenna, and RFID chip together in the same ultra-thin substrate is proposed to solve the integration density limitation problem of the microsystem. Compared with the lightest reported microstimulator of cyborg insects, the weight reduced by almost 60%. The behavior control experiments are established to verify the control functionalities of this wireless stimulator. Experimental results demonstrate that the proposed wireless ultra-lightweight microstimulator is capable of outputting stimulus waveforms into the bee's brain, and controlling the crawling deflection of cyborg bees.