UHF-RFID tag antenna using diamond structure and rectangular loop

This paper proposes the UHF RFID tag antenna design for operation of the frequency band 920-925 MHz corresponding to the standard of UHF RFID in Thailand. The tag antenna fabrication from the thin FR4 substrate (ε_r = 4.3) with the thickness of substrate of 0.25 mm. The pattern of the tag antenna is omni-directional one. The tag antenna design is used rectangular loop matching technique for matching between the tag antennas with IC chip with the impedance of 21.29-j191.7 Ω at the frequency of 922.5 MHz that is the center frequency. The meander line structure can be decrease the size of tag antenna to compact size.