Miniaturized Elliptical Slot Based Chipless RFID Tag for Moisture Sensing

Abstract

This paper presents a compact 10-bit chipless radio frequency identification (RFID) sensor tag. The proposed structure has overall size of 22.8 mm×16 mm and possesses the capability of identification of data as well as moisture sensing of the tagged objects. The resonating structure comprises of elliptically shaped slots in a nested loop manner, investigated for three substrates that are Rogers RT/duroid®/5880, Taconic (TLX-0) and Rogers RT/duroid ®/5870. The prototype is fabricated by using Rogers RT/duroid®/5880, and moisture sensing is realized by deploying heat-resistant sheet of Kapton®HN (DuPontTM) on the smallest slot considered as sensing slot over the aspired frequency spectrum of 3.5 GHz-15.5 GHz. The proposed tag is quite suitable for cost effective applications and can be deployed on the conformal surfaces for identification and sensing purposes.