Athena - RFID Tag Metrics

Abstract

In this thesis we have developed a Metric which is a numerical value representing the readability and performance characteristic of an RFID tagged object. The metric value ranges from 0 -100 and is given a unit of Athena, where a higher number specifies a better performing tag. The major parameters on which the metric value depends are frequency at which RFID system is working, transmitted power by the reader, and the received signal strength from the tag. All the parameters used for the Metric evaluation are well within the FCC regulations for passive UHF RFID system. Choosing the best performing tag for the give application is utmost important task to be followed before starting any RFID application. It is difficult because of the number of commercially available tags today. The methodology developed to calculate the metric may be performed with off-the-shelf readers and tags in a basic environment. The resulting metrics correlate strongly to the readability of the tagged objects in practice. As there are very many factors affecting the readability of the tag, ranging from frequency, power to the object which is to be tagged, it is very important to test the tags and analyze the results to gain an insight into the impact these factors on the tags performance. The metric is a numerical value which compares the general readability of the tags combining the effects of all the above mentioned parameters. The experiments to design the metric were carried out using two RFID reader systems and used many different kinds of tags and products of general use. A comparison of different experiments shows the readability differences not only between different products but also between the two different readers used. Along with the lab environment (close to the practical environment) the tests were also carried in anechoic chamber to know the ideal condition performance of RFID tags.