An approach for Synchronous Reading of Near-Field Chipless-RFID Tags

Abstract

In this contribution, we propose a new approach for near-field chipless-RFID systems with sequential bit reading where the bits are read synchronously. The tags are implemented as a chain of rectangular metallic patches etched or printed on a dielectric substrate at predefined and equidistant positions. Tag encoding is achieved through the size of the patches, where each patch corresponds to a bit of information. For tag reading, two resonators are used; one of them is able to detect the presence of rectangular patch (regardless of its size); the other one distinguishes between the large and the small patches. Thus, the former is used to determine the read time of the second one, and hence acts as a clock for synchronous reading. Both resonators are single loop complementary split ring resonators (CSRR) etched one inside the other in the ground plane of a microstrip line, with the slits etched at the same angular position (in order to avoid inter-resonator coupling). This working principle is validated in this paper.