A Multifrequency Passive Sensing Tag With On-Chip Temperature Sensor and Off-Chip Sensor Interface Using EPC HF and UHF RFID Technology Hannes Reinisch, Student Member , IEEE , Martin Wiess flecker, Student Member , IEEE , Stefan Gruber, Student Member , IEEE, Hartwig Unterassinger , Student Member , IEEE, Günter Hofer, Michael Klamminger

Abstract

State-of-the-art passive RFID tags are limited in terms of functionality and operating range due to the limited power that can be converted from the electromagnetic field. This is why state-of-the-art wir eless sensor systems are mostly battery-based if a high operating range is required. The proposed ultralow-power on-chip sensor u nit and off-chip sensor interface which provides enough energy to supply various sensors with a power consumption up to the milliwatt range make it possible to remotely power the proposed RFID tag and use it as wireless sensor node. Equipping sensor nodes with RFID functionality not only enables identi fication and logistic applications but also an easy integration of the sensing tag into existing RFID systems. Exploiting the different char a c t e r i s t i c so fH Fa n dU H FR F I D systems, namely the large operating range in UHF and the high available power in HF, increases the flexibility and applicability of wireless sensor nodes. This paper presents a remotely powered multifrequency sensing tag according to the EPC HF and EPC Class 1 Gen 2 UHF standard developed in a 0.13- m low-cost CMOS process. Input powers of 10.3 or 7.9 dBm at a fre- quency of 900 MHz are necessary to operate the sensing tag with activated on-chip sensor unit or off-chip sensor interface, respectively.