Wideband and material-insensitive RFID tag antenna design utilizing double-tuning technique
- Resource Type
- Conference
- Authors
- Xi, Jingtian; Ye, Terry T.
- Source
- 2011 IEEE International Symposium on Antennas and Propagation (APSURSI) Antennas and Propagation (APSURSI), 2011 IEEE International Symposium on. :545-548 Jul, 2011
- Subject
- Fields, Waves and Electromagnetics
Components, Circuits, Devices and Systems
Signal Processing and Analysis
Antennas
Bandwidth
Antenna measurements
Radiofrequency identification
Frequency measurement
Impedance
Mathematical model
UHF RFID
tag
wideband
material-insensitive
double-tuning
- Language
- ISSN
- 1522-3965
1947-1491
Wideband RFID tag antennas are highly desired for global applications. Moreover, the wideband feature makes tags less sensitive to the external detuning. This paper presents a circuit-based bandwidth-enhancement theory by applying the double-tuning technique to tag antennas. Conditions of the optimum double-tuning and the maximum bandwidth out of double-tuning are derived. Closed-form equations are provided to facilitate the bandwidth optimization and predication. Similarities and differences between the optimum double-tuned matching network and the equal-ripple two-stage bandpass filter have been discussed. In particular, a simplified design approach of double-tuned tag antennas is developed by examining the antenna impedance. An exemplary double-tuned tag antenna delivers a 10-dB bandwidth of 860∼958 MHz on paper, and exhibits the material-insensitive feature to accommodate dielectrics of low-to-medium permittivity.