Maryam Gharaei Jomehei1 , Samad Sheikhaei1 and Behjat Forouzandeh1
(1)
Nanoelectronics Center of Excellence, School of Electrical and Computer Engineering, University of Tehran, Tehran, Iran
Maryam Gharaei Jomehei
Email: m.gharaie@ut.ac.ir
Received: 8 August 2012Revised: 22 January 2013Accepted: 24 January 2013Published online: 8 February 2013
Abstract
In order to reduce the power consumption of RFID tags and increase the reading range of RFID systems, this paper proposes an ASK demodulator that uses a new approach to reduce the threshold voltage of diode connected MOS transistors as an obstacle in the design of the envelope detector. Also, an ultra low power comparator is used for further power reduction. This circuit has been simulated in a 0.18 μm CMOS technology to satisfy EPC Class 1 Generation 2 standard protocol emphasizing on the reduction of power consumption. The proposed circuit can correctly demodulate the minimum input RF signal amplitude of 180 mV for modulation depths of 55–100 % with 40–160 kb/s data rates. A total power consumption of less than 290 nW is achieved at a 1.2 V power supply. Effects of the input signal additive white noise as well as the process and temperature variations on the signal demodulation is also investigated in this paper.
Keywords
ASK demodulatorDynamic comparatorModulation indexRadio frequency identificationUltra low powerWhite noise
Maryam Gharaei Jomehei received her B.Sc. degree in Electrical Engineering from Ferdowsi University of Mashhad, Mashhad, Iran in 2009. Since September 2010, she has been an M.Sc. student and a research assistant in Advanced Data Communications Circuits and Systems Laboratory at School of Electrical and Computer Engineering of University of Tehran, Iran. Her research interests are analog and mixed-mode integrated circuit design with an emphasis on biomedical applications,