A Reconfigurable Carrier Leakage Canceler for UHF RFID Reader Front-Ends

This paper presents a new reconfigurable carrier leakage canceler for UHF RFID readers, using a directional coupler and an impedance tuning circuit to improve the sensitivity of the receiver. The impedance tuning circuit, which consists of electrically tunable passive components, can be adaptively tuned to have an optimum reflection coefficient for carrier leakage cancellation. In order to secure the good carrier leakage cancellation performance over the wide operating frequency band, PIN and varactor diodes are used as a variable resistor and a capacitor, respectively, for the impedance tuning circuit. The implemented reconfigurable carrier leakage canceler exhibits more than 65 dB of carrier leakage cancellation over a wide frequency band of 100 MHz, from 860 to 960 MHz when the control voltages of the PIN and varactor diodes are adjusted. As a result, a 15 dB improvement of receiver sensitivity, and 30% improvement of the recognition range have been achieved, respectively, using commercial RFID tags.

[1]  Hyoung-Hwan Roh,et al.  Adaptive TRX isolation scheme by using TX leakage canceller at variable frequency , 2008 .

[2]  P. Pursula,et al.  UHF RFID Reader With Reflected Power Canceller , 2009, IEEE Microwave and Wireless Components Letters.

[3]  Moon-Que Lee,et al.  RFID Reader Front-End Having Robust Tx Leakage Canceller for Load Variation , 2009, IEEE Transactions on Microwave Theory and Techniques.

[4]  Leena Ukkonen,et al.  Passive UHF RFID in Paper Industry: Challenges, Benefits and the Application Environment , 2009, IEEE Transactions on Automation Science and Engineering.

[5]  J. Grajal,et al.  A detailed study and implementation of an RPC for LFM-CW radar , 2006, 2006 European Microwave Conference.

[6]  Bomson Lee,et al.  A Long-Range UHF-Band Passive RFID Tag IC Based on High- $Q$ Design Approach , 2009, IEEE Transactions on Industrial Electronics.

[7]  Xiao-Wei Shi,et al.  A new directional coupler for UHF RFID reader , 2008 .

[8]  A. Sadeghfam,et al.  Electrically Tunable Bandpass Filter with Integrated Carrier Suppression for UHF RFID Systems , 2008, 2008 38th European Microwave Conference.

[9]  P. Nikitin,et al.  Sensitivity and Impedance Measurements of UHF RFID Chips , 2009, IEEE Transactions on Microwave Theory and Techniques.

[10]  Minsu Jeong,et al.  A UHF Mobile RFID Reader IC with Self-Leakage Canceller , 2007, 2007 IEEE Radio Frequency Integrated Circuits (RFIC) Symposium.

[11]  Roc Berenguer,et al.  Full Passive UHF Tag With a Temperature Sensor Suitable for Human Body Temperature Monitoring , 2010, IEEE Transactions on Circuits and Systems II: Express Briefs.

[12]  Jong-Won Yu,et al.  Balanced circulator structure with enhanced isolation characteristics , 2008 .

[13]  Moon-Que Lee.  Lumped directional coupler with a varactor tuned reflector for RFID applications , 2009, IEICE Electron. Express.

[14]  Jenshan Lin,et al.  Range correlation and I/Q performance benefits in single-chip silicon Doppler radars for noncontact cardiopulmonary monitoring , 2004, IEEE Transactions on Microwave Theory and Techniques.

[15]  Wan-Kyu Kim,et al.  A high isolated coupled-line passive circulator for UHF RFID reader , 2008 .