Analysis, design and implementation of semi-passive Gen2 tag

Abstract

An EPC <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">global</sub> Gen2 compatible semi-passive (or be called battery-assisted passive) tag is proposed. The transmission link is studied to optimize power distribution in a backscatter RFID system. For long read range consideration, design targets for low power tag are given. The tag chip is implemented in SMIC 0.18 mum standard CMOS technology. A high efficiency AC-DC charge pump serves as a rectifier. A low power wake-up circuit detects the input energy level and controls a button cell battery to supply the chip. The equivalent tag power is 230 nW by measurement.