Wideband adaptive isolator for UHF RFID reader

Authors :: Ilkka Marttila
Kaj Nummila
Pekka Pursula
Source :: Pursula, P, Marttila, I & Nummila, K 2009, ' Wideband adaptive isolator for UHF RFID reader ', Electronics Letters, vol. 45, no. 12, pp. 636-637 . https://doi.org/10.1049/el.2009.0512
Publication Year :: 2009
Publisher :: Institution of Engineering and Technology IET, 2009.
Abstract: A wideband adaptive isolator for a UHF RFID reader with a minimum component count is introduced. The operation of the device is based on a reflection from a variable load, which is connected to a port of a hybrid coupler. The other ports are connected to the receiver (RX), transmitter (TX) and antenna ports of the reader. The isolator provides an isolation of 50 dB from TX to RX at the 800 MHz-1 GHz band, covering the worldwide UHF RFID bands. The adaptive system ensures high isolation up to an antenna return loss of 6 dB, or reflection coefficient of 0.5. The measured loss in the TX-to-antenna and antenna-to-RX paths is 4 dB.