Exploring Passive RFID Tag Use For Sensory Technology

Monday, April 26, 2021

In his research paper, “RTSense: RFID based Temperature Sensing,” WNCG alumnus Dr. Swadhin Pradhan and Prof. Lili Qiu explore how passive RFID tags could address the problem of battery-dependent sensory devices. 

Passive RFID tags are made up of two components: an antenna and an integrated circuit chip (the actual tag). The circuit chips have no energy of their own—they don’t have a battery and are also not connected to an outlet. They operate purely by absorbing radio frequency energy transmitted from RFID antennas. The radio frequency wave from the antenna energizes the tag. Then, it sends back information encoded in its memory back to the antenna. These aspects of passive RFID tags make them perfect for sensory appliances. 

Pradhan and Qiu designed an analytical model, RTSENSE, that observes the change in electrical resistance in a passive tag caused by temperature change. RTSENSE consists of 2 stages, calibration and estimation. The calibration is a quick but essential step performed during installation that does not need to be repeated even when tag orientation or distance changes. During this step, the reader continuously reads the tag-pair and records all responses. This stage aims to figure out the effect temperature has on this system. With this information, the system is able to effectively estimate temperature in the estimation stage. Temperature is measured by recording the phase difference during 10 seconds. This average is then put in a regression model that estimates temperature. 

Read the full article, including a link to the research paper, via the Department of Computer Science.