Wireless Power Transfer by Self-biased Magnetoelectric Laminate for Biomedical Implants

Magnetoelectric (ME) wireless power transfer (WPT) is becoming an important topic in the field of biomedical implants. Implantable ME WPT receivers have potential safety, size, and convenience advantages over alternative methods (i.e. inductive, far-field RF, and acoustic). However, for optimal performance, ME devices need some method to apply a DC bias magnetic field. To overcome the DC bias problem, this paper investigates self-biased ME laminates using the magnetization grading approach. We experimentally characterize the voltage and power performance of multi-layer self-biased ME laminates as a function of pre-magnetizing field. We demonstrate devices made of Metglas, Ni, and PZT of 0.05 cm3 in size that can generate ~250 μW from an applied 130 μT AC field with no DC field bias. This size, power, and AC magnetic field combination makes these laminates attractive for powering biomedical implants.