Summary
International Symposium on Antennas and Propagation
2009
Session Number:3B3
Session:
Number:3B3-1
Reading Technique for Use with 2.45-GHz-Band Small RFID Tags
Peng Wang, Hiroyuki Koga, Shigeki Obote, Kenichi Kagoshima,
pp.867-870
Publication Date:2009/10/21
Online ISSN:2188-5079
Summary:
The 2.45-GHz-band small passive radio-frequency identification (RFID) tag [1] is only several millimeters in size, and is ideal for use with very small objects to which dipole tags cannot be attached. However, the small RFID tag available in today’s market has poor impedance-matching characteristic and radiation efficiency, and cannot provide enough power to an integrated circuit (IC) chip by itself. To solve this problem, two techniques have been proposed for reading the tag. One uses a reader antenna consisting of parallel transmission lines [2]. The other uses an inductive coupling feed structure [3], [4]. In a previous work, we investigated placing a half-wavelength metallic wire beside the small RFID tag [4]. This paper extends that work by reporting development of an adapter that uses a square half-wavelength meander-line (ML) conductor, placed in the vicinity of the tag. Simulations and experiments confirm the effectiveness of this technique. The conductor improves the impedance-matching characteristic and radiation efficiency of the tag and its square shape relaxes requirements on alignment.