Title :
Vector backscattered signal analysis of piggyback modulation for passive UHF RFID Tags
Author :
Chen, Huan-Yang ; Bhadkamkar, Atul ; Chou, Tzu-Han ; Van der Weide, Daniel W.
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of Wisconsin, Madison, WI, USA
Abstract :
We describe a “piggyback modulation” technique to integrate sensing functions with existing standard passive UHF RFID tags through electromagnetic coupling. Instead of focusing on the scalar backscattered power that is proportional to the radar cross section (RCS), we present vector analysis and measurement for backscattered signals with piggyback modulation. Measuring both amplitude and phase of the backscattered wave makes advanced demodulations possible. Quasi-4-QAM demodulation is proposed to reduce the interferences between two independent data streams and improve the bit error rate. The measurement setup, experimental results, and demodulation analysis for the conventional ASK and quasi-4-QAM are presented.
Keywords :
amplitude shift keying; electromagnetic coupling; error statistics; quadrature amplitude modulation; radar cross-sections; radiofrequency identification; ASK; RCS; bit error rate; electromagnetic coupling; passive UHF RFID tags; piggyback modulation technique; quasi-4-QAM demodulation; radar cross section; vector backscattered signal analysis; Amplitude shift keying; Application specific integrated circuits; Bit error rate; Couplings; Demodulation; Radiofrequency identification; ASK; UHF RFID; backscattering; piggyback modulation; quasi-4-QAM; sensor; vector signal analysis;
Conference_Titel :
Microwave Symposium Digest (MTT), 2011 IEEE MTT-S International
Conference_Location :
Baltimore, MD
Print_ISBN :
978-1-61284-754-2
Electronic_ISBN :
0149-645X
DOI :
10.1109/MWSYM.2011.5972884
