Nanoelectronics Center of Excellence, School of Electrical and Computer Engineering, University of Tehran, Tehran, Iran Maryam Gharaei Jomehei
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, analysis and design of RFID systems and low power high speed data converters.
received the B.Sc. and M.Sc. degrees in electrical engineering from Sharif University of Technology, Tehran, Iran, in 1996 and 1999, respectively, and the Ph.D. degree from the University of British Columbia, Vancouver, BC, Canada, in 2008. He was engaged in research and design engineering at Sharif University of Technology. He also worked in industry for a couple of years. In September 2009, He joined the Department of Electrical and Computer Engineering at University of Tehran, Iran, where he is currently an Assistant Professor. His research interests are analog, mixed-signal, and RF integrated circuits design, and his current research projects include circuit design for wireless transceivers, high-speed serial links, high-speed analog-to-digital converters, and on-chip dc–dc power converters.
received M.S. degree in the field of Electrical Engineering from University of Tehran, Tehran, Iran in 1980 and her Ph.D. in the field of Electrical Engineering from the University of Birmingham, U. K. in 1997. She joined the Department of Electrical and Computer Engineering at University of Tehran, Iran, where she is currently an Associate Professor and involved in various courses and labs such as analog/digital electronics, SOI and quantum computing and VLSI. Her current research interests include analog and mixed signal circuits, SOI devices, quantum computing design and implementation. She is also author or coauthor for plenty of journal and conferences papers in various filed of electronics and hardware engineering. 1 Introduction
Today’s RFID systems have attracted more and more attentions of industries and academic centers for their low cost and extensive applications. It has motivated their efforts to improve RFID technology especially UHF RFID tags . One of the major goals of these efforts is the improvement of the operating range, which is...