NanoNeuroRFID: A Wireless Implantable Device Based on Magnetoelectric Antennas

A major obstacle during the design of brain-computer interfaces is the unavailability of a neural implantable device that is μ-scale in size, wireless, self-powered, and long-lasting. Current state-of-the-art implantable devices suffer from various limitations. Electromagnetic-based wireless devices are big in size because of their large antenna, which must be larger than onetenth of the wavelength of the operational frequency. Ultrasound-based wireless devices, in addition to their low data rate, have a massive loss in the skull and need an intermediate electromagnetic transceiver under the skull. Furthermore, almost all state-ofthe- art wireless devices use micro-electrodes for neuronal recording, which are not reliable in long-term monitoring applications because of direct contact between the tissue and metal electrodes. In this paper, we propose a novel wireless and ultra-compact implantable device termed NanoNeuroRFID. At the core of this device there is a Magnetoelectric (ME) antenna array. ME antennas are smart and ultra-miniaturized (<200μm diameter), and can perform multiple tasks: 1) They can harvest electromagnetic energy to power the NanoNeuroRFID system. Their limit of detection for RF magnetic fields is 40pT. 2) They can sense quasi-static neuronal magnetic fields as small as 200pT without a direct contact to the tissue, allowing a long lifetime and reliable neural recording. 3) They can communicate with an external transceiver, and their operational frequency could be 10s to 100s of MHz where tissue loss is small.