Title :
An Electrically Small Spherical UHF RFID Tag Antenna With Quasi-Isotropic Patterns for Wireless Sensor Networks
Author :
Ryu, Hong-Kyun ; Jung, Gichul ; Ju, Dea-Keun ; Lim, Sungkyun ; Woo, Jong-Myung
Author_Institution :
Dept. of Radio Sci. & Eng., Chungnam Nat. Univ., Daejeon, South Korea
fDate :
7/2/1905 12:00:00 AM
Abstract :
An electrically small spherical UHF (911.25 MHz) radio frequency identification (RFID) tag antenna is proposed. A dipole-typed RFID tag antenna is wound into a spherical shape to achieve small size and quasi-isotropic pattern. The overall diameter of the antenna is 25 mm (0.076??), and the resulting electrical size is a kr of 0.24. A short stub is employed for good conjugate impedance matching with a RFID chip (Zchip = 14 - j145 ??). The designed antenna has a -10-dB bandwidth of 7 MHz (0.77%) and the maximum readable distance of 132 cm at 5.2 W EIRP.
Keywords :
UHF antennas; antenna radiation patterns; dipole antennas; impedance matching; radiofrequency identification; wireless sensor networks; UHF RFID tag antenna; bandwidth 7 MHz; dipole-typed RFID tag antenna; impedance matching; quasi-isotropic patterns; radio frequency identification tag antenna; size 132 cm; size 25 mm; wireless sensor networks; Electrically small antennas; quasi-isotropic patterns; radio frequency identification (RFID) tag antennas;
Journal_Title :
Antennas and Wireless Propagation Letters, IEEE
DOI :
10.1109/LAWP.2010.2043046
