IEICE Electronics Express
Online ISSN : 1349-2543
ISSN-L : 1349-2543
LETTER
Lumped directional coupler with a varactor tuned reflector for RFID applications
Moon-Que Lee
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2009 Volume 6 Issue 2 Pages 129-134

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Abstract

In this paper, a lumped directional coupler with a tunable reflector is proposed for an UHF passive RFID front-end system in which the sensitivity is limited by the isolation between transmitter and receiver. The proposed directional coupler can tunably eliminate TX-to-RX leakage caused by both the imperfect isolation of a directional coupler and the mismatch of antenna impedance which may be changed due to near-field environment. The measured result shows excellent TX-to-RX isolation above 70dB at 910MHz and 55dB over Korean UHF-RFID band.

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© 2009 by The Institute of Electronics, Information and Communication Engineers
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