An Electrically Small, 16.7 m Range, ISO18000-6C UHF RFID Tag for Industrial Radiation Sources

We present an electrically small, long range passive ultra high frequency (UHF) radio frequency identification (RFID) tag suitable for mounting on the cylindrical metal enclosure of an industrial radiation source. The RFID tag antenna consists of a C-shaped loop over a ground plane coupled to the metal cylinder. The tag is 41 mm in diameter and 6.48 mm thick. From simulation, the tag antenna is found to have an input impedance of 16+j229 at 912.5 MHz. This antenna is designed to match an ISO18000-6C UHF RFID chip having a read sensitivity of -18 dBm. The simulated realized gain of the proposed antenna is -0.3 dBi. Read range measurements are presented for different orientations and angular positions in three different scenarios. When mounted to the metal cylinder and read by an RFID reader with an EIRP of +40.5 dBm, the measured maximum read range of the proposed tag is 16.7 m in its most favorable orientation.