Feasibility of backscatter communication using LoRAWAN signals for deep implanted devices and wearable applications

Identifier:  imarina:9138864

Handle: https://hdl.handle.net/20.500.11797/imarina9138864

Authors:  Lazaro, M; Lazaro, A; Villarino, R

Abstract:
© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This paper presents a method for low data rate transmission for devices implanted in the body using backscattered Long Range (LoRa) signals. The method uses an antenna loaded with a switch that changes between two load impedances at the rate of a modulating oscillator. Consequently, the LoRa signal transmitted by a LoRa node is reflected in the adjacent channels and can be detected with a LoRa gateway tuned to the shifted channels. A prototype developed to operate at Medical Implant Communication Service (MICS) and the Industrial Scientific and Medical (ISM) 433 MHz band is presented. The prototype uses a commercial ceramic antenna with a matched network tuned to the frequency band with high radiation efficiency. The effect of the coating material covering the antenna was studied. Simulated and experimental results using a phantom show that it is feasible to read data from deep implanted devices placed a few meters from the body because of the high sensitivity of commercial LoRa receivers.