1146 IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 43, NO. 5, MAY 2008 A Universal UHF RFID Reader IC in 0.18-μm CMOS Technology Pradeep Basappa Khannur, Senior Member, IEEE, Xuesong Chen, Dan Lei Yan, Dan Shen, Bin Zhao, M. Kumarasamy Raja, Ye Wu, Rendra Sindunata, Wooi Gan Yeoh, Member, IEEE, and Rajinder Singh, Member, IEEE Abstract—A highly integrated UHF RFID reader IC in 0.18- m CMOS process covering the entire 860 MHz to 960 MHz RFID band supporting the EPCglobal™ Class-1 Generation-2 and ISO-18000-6A/B/C standards is presented. The IC features a transmitter with an output of 10 dBm and a receiver with sensitivity of 96 dBm in listen-before-talk mode (LBT) and 85 dBm in talk-mode. Direct-conversion architecture is used for the receiver for a high level of integration and low power con- sumption. On-chip dual-loop synthesizer generates high-purity LO signal with frequency resolution of 50 kHz and phase noise of 101 dBc/Hz at 100 kHz offset over the entire 860 to 960 MHz band. The IC integrates 10-bit DACs, pulse-shaping filters, an IQ modulator and a power amplifier in the transmit chain and a low-noise amplifier (LNA), an IQ downconverter, channel-select filters, variable-gain amplifiers and 10-bit ADCs in the receive chain. On-chip ASK demodulator provides demodulated I and Q raw data outputs. The chip has a die area of 6 mm 6 mm. It operates over a wide range of voltage and temperature, from 1.6 V to 2.0 V and from 25 C to 75 C and consumes 540 mW from a 1.8 V supply at 25 C. Index Terms—Backscatter modulation, CMOS, passive transponder, reader, RFID, RFIDinterrogator, UHF. I. INTRODUCTION R ADIO-FREQUENCY identification (RFID) is probably the best choice for automatic identification, which calls for non-line-of-sight, wireless, contactless, high data rate, mul- tiple tag identification, lowest operating cost, long read range, operation in dirt/damp environment and re-programmability of the tag. At present the cost of the RFID system, especially that of tag, is the main concern for replacing barcode systems. Once the cost of a tag approaches that of a barcode, RFID may re- place barcode in most of the barcode applications and will also lead to emergence of newer applications. A few promising appli- cations of RFID are supply chain management, access control, airport baggage handling, auto registration, non-stop toll collec- tion, theme parks, etc. The read/write range performance of a RFID system depends mainly on the choice of frequency, radiated power from the reader, sensitivity of tag, tag’s modulation efficiency, data rate, Manuscript received September 14, 2007; revised February 8, 2008. The authors are with the Institute of Microelectronics, A*STAR, Singapore Science Park II, Singapore, 117685 (e-mail: pradeep@ime.a-star.edu.sg, khannur@ieee.org; chenxs@ime.a-star.edu.sg; yandl@ime.a-star.edu.sg; mars_shen9385_cn@sina.com; zhaobin@ime.a-star.edu.sg; raja@ime.a-star. edu.sg; maggie.wuyeus@gmail.com; rendra@ime.a-star.edu.sg; wooigan@ ime.a-star.edu.sg; rajinder@auxineon.com). Digital Object Identifier 10.1109/JSSC.2008.920355 reader receiver sensitivity in the presence of self-jammer signal and location of the tag [1]. Near-field inductive-loop passive RFID systems, which operate at the low-frequency (LF) of ei- ther 125 or 134 kHz or high frequency (HF) of 13.56 MHz, are limited to a read-range of approximately 1 m. Ultra-high fre- quency (UHF) RFID systems operate in the Industrial–Scien- tific–Medical (ISM) bands between 860 and 960 MHz. They have much longer read range of 3 m to 10 m for a passive tag. EPCglobal™ Class-1 Generation-2 [2] and ISO 18000-6C [3] are the important governing UHF (860 MHz to 960 MHz) RFID standards, which define the air interfaces, being widely adapted by the industry. The regulations, ETSI EN 302 208–1 [4] in Eu- rope and FCC Title 47, Part 15 [5] in United States of America, define limitations on spurious emissions. These universal air in- terface standards and regulations along with the advancement in tag technology are helping the widespread adoption of UHF RFID systems. A. Components of a UHF RFID System A UHF RFID system consists of reader(s), tag(s) and a computer (optional) as shown in Fig. 1. The reader(s) sends information to one or more tags by modulating an RF carrier using double-sideband amplitude-shift-keying (DSB-ASK), single-sideband amplitude-shift-keying (SSB-ASK) or phase-reversal amplitude-shift-keying (PR-ASK) modulation at a bit rate ranging from 26.7 to 128 kbps [2], [3]. Modulation is achieved using a pulse-interval-encoding (PIE) format. Here, data is passed to the tag by pulsing carrier wave at differing time intervals to indicate a 0 or 1. The tag receives both the information and the operating energy from the reader’s RF signal. If the tag lies within the reader’s range, an alternating RF voltage is induced on the tag antenna which is rectified to provide a direct current (DC) supply voltage for the tag’s operation. The tag responds by modulating the impedance placed on the antenna terminals. In doing so, it backscatters an information signal to the reader. The reader demodulates and decodes the tag’s data. B. Problem of Self-Jammer at the Reader Receiver Input A passive UHF RFID system is a half duplex system [1]. The biggest differentiator of an RFID transceiver is the require- ment to handle large transmitter leakage during tag reception [6] which calls for the design of a wide dynamic range receiver with a very high input 1-dB compression point. Other option is to use some sort of self-jammer cancellation technique, which can be realized either on-chip [7] or off-chip. Reader IC pre- sented in this paper requires external self-jammer cancellation 0018-9200/$25.00 © 2008 IEEE