Flexible battery-free wireless electronic system for food monitoring

Conventional battery powered and rigid wireless electronic systems are needed to be improved for adapting to the actual food quality and safety monitoring. This paper aims to propose and develop a flexible battery-free wireless electronic system (FBES) for food monitoring by the laser direct scribing on commercial polyethylene terephthalate/polyimide/copper (PET/PI/Cu) film. The FBES could acquire the temperature, weighing and pH sensor data, and transmit to the wireless reader by radio frequency identification/near field communication (RFID/NFC) with 13.56 MHz. The FBES could harvest the RF energy from the wireless reader and battery-free power for the food sensors and sensor acquisition module. The surface microscope image of the flexible Cu circuit demonstrated that the laser direct scribing could be easily applied to fabricate the flexible electronic system with low complex process and low cost. The food temperature, moisture loss rate (MLR) and pH monitoring applications have been evaluated. The application evaluation results demonstrated that the proposed FBES has a potential application for many kinds of food monitoring by harvesting the RF energy with continuous or on-demand. It could improve transparency and guarantee the quality and safety of food.