Integrated microsystem with humidity, temperature and light sensors for monitoring the preservation conditions of food

This paper presents an integrated microsystem for tracing food information and monitoring its preservation conditions. The system embeds humidity, temperature, and light intensity sensors with the respective interface circuits and also an A/D converter. The target application of the microsystem is a smart label, which will include an RFID transponder for collecting energy and transmitting data, as well as a micro-battery for energy storage. The proposed microsystem, designed in a 0.18μm CMOS technology, achieves better than 0.5°C and 6W/m² accuracy regarding temperature and light intensity respectively, while consuming less than 90μA with 1.8V supply. On-chip capacitor dielectric permittivity, based on Sylgarl 184 polymer, has been optimized for best relative humidity response at ambient temperature for the given microsystem.