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Adaptive TRX isolation scheme by using TX leakage canceller at variable frequency
Author(s) -
Jung JinWoo,
Roh HyoungHwan,
Kwak HoGil,
Sub Jeong Myoung,
Park JunSeok
Publication year - 2008
Publication title -
microwave and optical technology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 76
eISSN - 1098-2760
pISSN - 0895-2477
DOI - 10.1002/mop.23592
Subject(s) - attenuator (electronics) , circulator , leakage (economics) , ultra high frequency , microcontroller , electrical engineering , microwave , engineering , electronic engineering , telecommunications , physics , attenuation , optics , economics , macroeconomics
This article presents a TX leakage cancellation scheme for UHF RFID readers. A prototype is implemented on a UHF RFID reader board, which includes a circulator, directional coupler, microcontrol unit (MCU)‐controlled variable attenuator, and phase shifter. The difference between a conventional TX leakage canceller and this new one is that, reflected signals caused by mismatches between the front‐end and the antenna are included; in addition, high isolation is supplemented at variable frequencies. About 10% of the frequency range is recovered by the best suited parameter values that provide a predetermined process of MCU; and thus, peak isolation characteristics are constantly guaranteed at each center frequency by phase‐shifted signal generation that follows references stored in MCU. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2043–2045, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23592