DocumentCode :
1764894
Title :
Adaptive TX Leakage Canceler for the UHF RFID Reader Front End Using a Direct Leaky Coupling Method
Author :
Min-Su Kim ; Sung-Chan Jung ; Jonghyuk Jeong ; Hyungchul Kim ; Mincheol Seo ; Junghyun Ham ; Cheon-seok Park ; Youngoo Yang
Author_Institution :
Samsung Electron. Co. Ltd., Yongin, South Korea
Volume :
61
Issue :
4
fYear :
2014
fDate :
41730
Firstpage :
2081
Lastpage :
2087
Abstract :
This paper presents a new adaptive leakage canceler based on a direct leaky coupling method for an RF front-end circuit of an ultrahigh-frequency radio-frequency identication (UHF RFID) reader. For better receiver sensitivity, the leakage signal from a transmitter (TX) to a receiver (RX) should be suppressed. Compared with conventional methods, the proposed TX leakage canceler has a much simpler circuit configuration due to the direct leaky coupling circuit (LCC) and the phase shifter on the RX path. The LCC includes a variable resistor, a variable capacitor, and an inductor, which allow us to control the magnitude and the phase of the coupled TX signal. The phase shifter that is located on the RX path even before the low-noise amplifier controls the phase of the TX leakage signal. For the worldwide RFID bands that spans from 840 to 960 MHz, the canceler must be adaptively controlled by using a microcontroller and control circuits. For the experimental verification, an RF front-end circuit with the proposed adaptive TX leakage canceler was designed and implemented for the UHF RFID reader. The implemented RF front-end block occupies only 54 ×54 mm2, except for the control block. From 840 to 960 MHz, the adaptively controlled RF front-end circuit exhibited significant cancelation characteristics for the TX-RX leakage signals. This results in more than twice longer reading distances for the commercial RFID tags compared with the cases without the adaptive canceler.
Keywords :
RLC circuits; UHF devices; low noise amplifiers; microcontrollers; phase shifters; radiofrequency identification; receivers; transmitters; LCC; RF front-end circuit; RX path; TX leakage canceler; TX-RX leakage signals; UHF RFID reader; adaptive leakage canceler; control circuits; direct leaky coupling circuit; direct leaky coupling method; frequency 840 MHz to 960 MHz; low-noise amplifier; microcontroller; phase shifter; ultrahigh-frequency radio-frequency identication reader; Direct leaky coupling method; TX leakage; leakage canceler; radio-frequency identification (RFID) reader; transmitter (TX);
fLanguage :
English
Journal_Title :
Industrial Electronics, IEEE Transactions on
Publisher :
ieee
ISSN :
0278-0046
Type :
jour
DOI :
10.1109/TIE.2013.2267932
Filename :
6530622
Link To Document :
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