@inproceedings{c7b499eb000d4e54b9a776ad8a8bb847,
title = "A passive circulator for RFID application with high isolation using a directional coupler",
abstract = "In this paper, a newly invented circulator for T/R switch of UHF radio-frequency identification (RFID) application is proposed to overcome TX-to-RX leakage problem. A microstrip coupled-line directional coupler is used for this passive circulator and the isolation characteristic is drastically improved not by complex method such as compensating phase velocity, but by considering both directional coupler itself and imperfect input impedance of the employed antenna. The measurement result of the proposed circulator using modified microstrip coupled-line directional coupler with employed antenna shows excellent TX-to-RX leakage suppression in the 860 MHz - 960 MHz, more than 45 dB enhancement at the center frequency compared to the conventional coupler. Experimental verification using RFID system is also performed to prove the validity of the proposed circulator.",
keywords = "Coupled line directional coupler, High isolation, RFID, TX-to-RX leakage",
author = "Kim, {Wan Kyu} and Lee, {Moon Que} and Kim, {Jin Hyun} and Lim, {Hyung Sun} and Yu, {Jong Won} and Jang, {Byung Jun} and Park, {Jun Seok}",
year = "2006",
doi = "10.1109/EUMC.2006.281252",
language = "English",
isbn = "2960055160",
series = "Proceedings of the 36th European Microwave Conference, EuMC 2006",
publisher = "IEEE Computer Society",
pages = "196--199",
booktitle = "Proceedings of the 36th European Microwave Conference, EuMC 2006",
address = "United States",
note = "36th European Microwave Conference, EuMC 2006 ; Conference date: 10-09-2006 Through 12-09-2006",
}