Metamaterial isolator for RFID based biomedical repeater system

This paper presents the design of a subwavelength electromagnetic band gap (EBG) isolator for a biomedical repeater device. The repeater device is meant to amplify the attenuated RF signal sent from reader antenna and retransmits it to a miniature implant sensor. The EBG isolator working at UHF RFID frequency of 900 MHz occupies an area of 3.1 cm × 2 cm. It increases isolation between orthogonal loops of the repeater device to more than 25 dB allowing for more than 20 dB gain for the amplifier.