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 and is wireless, self-powered, and long-lasting. The 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 one-tenth of the wavelength of the operational frequency. Ultrasound-based wireless devices, in addition to their low data rate, have massive loss in the skull and need an intermediate electromagnetic transceiver under the skull. Furthermore, almost all state-of-the-art wireless devices use micro-electrodes for neuronal recording, which are not reliable in long-term monitoring applications because of the 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 (<200 μm diameter) and can perform multiple tasks. First, can harvest electromagnetic energy to power the NanoNeuroRFID system. Their limit of the detection for RF magnetic fields is 40 pT; second, they can sense quasi-static neuronal magnetic fields as small as 200 pT without direct contact to the tissue, allowing a long lifetime and reliable neural recording; and third, they can communicate with an external transceiver, and their operational frequency could be 10 to 100 s of MHz, where tissue loss is small.