Ultra-compact dual-band smart NEMS magnetoelectric antennas for simultaneous wireless energy harvesting and magnetic field sensing

TLDR

Demand for ultra‑compact wireless implantable medical devices is high, yet existing micro‑coil technologies suffer from low power‑transfer efficiency, SAR compliance issues, and require direct electrode–tissue contact for differential voltage or current recording. The study presents an ultra‑compact dual‑band smart NEMS magnetoelectric antenna designed to simultaneously harvest wireless energy and sense ultra‑small magnetic fields. The antenna, measuring 250 × 174 µm², employs a magnetoelectric transduction mechanism to enable dual‑band operation for energy harvesting and magnetic field detection. The antenna achieves 1–2 orders of magnitude higher wireless power‑transfer efficiency than existing micro‑coils, meets SAR limits, and offers 300–500 pT magnetic‑field detectivity sufficient for recording neural magnetic fields.

Abstract

Abstract Ultra-compact wireless implantable medical devices are in great demand for healthcare applications, in particular for neural recording and stimulation. Current implantable technologies based on miniaturized micro-coils suffer from low wireless power transfer efficiency (PTE) and are not always compliant with the specific absorption rate imposed by the Federal Communications Commission. Moreover, current implantable devices are reliant on differential recording of voltage or current across space and require direct contact between electrode and tissue. Here, we show an ultra-compact dual-band smart nanoelectromechanical systems magnetoelectric (ME) antenna with a size of 250 × 174 µm 2 that can efficiently perform wireless energy harvesting and sense ultra-small magnetic fields. The proposed ME antenna has a wireless PTE 1–2 orders of magnitude higher than any other reported miniaturized micro-coil, allowing the wireless IMDs to be compliant with the SAR limit. Furthermore, the antenna’s magnetic field detectivity of 300–500 pT allows the IMDs to record neural magnetic fields.