DUAL-BAND UHF RFID TAG ANTENNA USING TWO ECCENTRIC CIRCULAR RINGS

A low profile dual-band passive Ultra High Frequency Radio Frequency Identification (UHF RFID) tag antenna designed to operate at two RFID bands allocated for use in Europe (865–868 MHz) and Japan (950–956 MHz) is proposed. The antenna has two eccentric circular rings of different radii to provide dual band response. An arc-shaped strip with Impinj Monza-4 IC chip is used to feed the two rings simultaneously by microstrip-line coupling-feed technique. The proposed design is simulated using Ansoft HFSS, and the prototype is fabricated. The return losses at 866 MHz and 952 MHz are measured to be −12.25 dB and −12.99 dB, respectively, which are in good agreement with the simulated results. The proposed antenna exhibits a 10 dB bandwidth of 9 MHz from 862 to 870 MHz and an 8 MHz 10 dB bandwidth from 949 to 956 MHz covering the UHF RFID bands in Europe and Japan. The maximum read ranges are measured to be around 3m in the 865–868 MHz band and 2.6 m in the 950–956 MHz band.