Enhance data encryption for chipless RFID tags with reference resonators

Abstract

This paper proposes a new frequency data encoding method, applicable to chipless RFID tags, allowing for N resonant elements, each of which has a fundamental resonant frequency and M shifted resonance frequencies around  can encode a much larger amount of data than the amount of data encoded by the OOK method. . To do this, the authors have also researched and solved thoroughly to design of passive structures which can resonate at predetermined desired frequencies with errors within allowable limits by applying the Particle Swarm Optimization algorithm (PSO) to find the optimal parameter . This result has overcome one of the biggest limitations of chipless RFID tags which is data encoding capacity while not increasing the size or complicating the structure of the tag.