A Compact EBG for High Isolation Between Two Very Closeby Wire-Antennas for RFID Tags

In this paper, we show a new scheme to tackle the problems of high electromagnetic-coupling, poor impedance-matching and degraded radiation-characteristics of two UHF-band RFID tag antennas, when they are very close. Using an inverted H-shaped EBG as a novel and compact structure, we insert it between the two antennas and prevent the unwanted interference and match the input impedance of both of the tag antennas. Also, the antenna gain of the two tags is -1.23 dBi which is larger than that of ordinary UHF-band tag antennas.