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 µm2 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.

9 10 -Abstract 11 Ultra-compact wireless implantable medical devices (IMDs) are in great demand for healthcare 12 applications, in particular for neural recording and stimulation. Current implantable technologies 13 based on miniaturized micro-coils suffer from low wireless power transfer efficiency (PTE) and 14 are not always compliant with the specific absorption rate imposed by the Federal Communications 15 Commission, particularly for deep brain implantation where field attenuation and tissue loss are 16 significant. Moreover, current implantable devices are reliant on recordings of voltage or current. 17This has two major weaknesses: 1) the necessary direct contact between electrode and tissue 18 degrades over time due to electrochemical fouling and tissue reactions, and 2) the necessity for 19 differential recordings across space. Here, we report, for the first time, an ultra-compact dual-band 20 smart nanoelectromechanical systems magnetoelectric (ME) antenna with a size of 250×174 µm 2 21 that can efficiently perform wireless energy harvesting and sense ultra-small magnetic fields such 22 designs and different operating frequencies. The ME antenna is based on ME FBAR (thin film 56 bulk acoustic wave resonator) working at 2.5 GHz; while the ME sensor is based on a ME NPR 57 (nano-plate resonator) with interdigitated electrode and an operation frequency of 215MHz. In this 58 paper we present the first ever smart ME antenna with unprecedented characteristics that are ideal 59 for IMDs: (1) ultra-compact antenna for highly efficient wireless power transfer efficiency and 60 data communication at GHz; (2) ultra-sensitive magnetometer capable of sensing picoTesla low-61 frequency fields by using MHz resonance; and (3) simultaneous operation at two different 62

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This article describes the development of a radio frequency (RF) platform for electromagnetically modulated signals that makes use of a software-defined radio (SDR) to receive information from a novel magnetoelectric (ME) antenna capable of sensing low-frequency magnetic fields with ultra-low magnitudes. The platform is employed as part of research and development to utilize miniaturized ME antennas and integrated circuits for neural recording with wireless implantable devices. To prototype the reception of electromagnetically modulated signals from a sensor, a versatile Universal Software Radio Peripheral (USRP) and the GNU Radio toolkit are utilized to enable real-time signal processing under varying operating conditions. Furthermore, it is demonstrated how a radio frequency signal transmitted from the SDR can be captured by the ME antenna for wireless energy harvesting.