Magnetoeletric Backscatter Communication for Millimeter-Sized Wireless Biomedical Implants

Magnetoelectric power transfer has shown remarkable promise for the development of wireless millimetric bioelectronic implants with its low tissue absorption, high efficiency, and low misalignment sensitivity. Utilizing the same physical mechanism for power and communication is critical for implant miniaturization. For the first time, we designed and demonstrated near-zero power magnetoelectric backscatter from mm-sized implants by exploiting the converse magnetostriction effects. The prototype system consists of an 8.2-mm3 wireless implant integrating an application-specific integrated circuit (ASIC) that achieves frequency-shift-keying backscattering via capacitive load modulation and a custom transceiver demodulating data through frequency-to-digital conversion. The magnetoelectric backscatter archives > 1 kbps data rate at the 335-kHz carrier frequency, with a communication distance greater than 2 cm and a bit error rate (BER) less than 1E-3.