Kaj Nummila

Applicability of Metallic Nanoparticle Inks in RFID Applications

Radio frequency identification (RFID) antennas for HF and UHF frequencies are ink-jet printed using commercially available silver nanoparticle ink. Quality factors of 5.3 and 9.4 are obtained for coil antennas targeted for 13.56 MHz when the printing and sintering process is repeated two and three times, respectively. The measured maximum effective aperture of the printed UHF antenna is only some decibels lower than that of an equivalent etched copper antenna and the maximum reading distance with 0.5 W (ERP) transmitted power is 3 m for continuous reading. These results suggest that obtaining a low enough series resistance for printed coils is challenging while printed RFID antennas for UHF do not set as strict requirements on conductivity. With a perfectly optimized structure, a UHF tag antenna printed in just one layer of ink can be practically equal in performance with the traditional etched copper and aluminum tags.

Monitoring environmental performance of the forestry supply chain using RFID

It is estimated that wood raw material worth of approximately @?5billion is wasted annually in Europe. The major reason for this is that the raw material is not used in the most efficient way as information needed regarding the wood raw material is not available throughout the supply chain. An automatic traceability system makes it possible to utilise raw material information efficiently throughout the forestry-wood production chain and to maximize the raw material yield, and to optimise and to monitor the environmental impact, by linking the relevant information to the traced objects. This paper describes novel RFID technology and traceability solutions that have been developed for the wood products industry. RFID-marking connects the physical objects with their database counterparts thus allowing automatic tracing of the objects. The architecture is needed to the dynamic and decentralised nature of the wood industry. The developed novel RFID based technology allows tracing of individual logs from the tree felling to the sawing of the logs at the saw mill. By combining the traceability and process information systems, new methods are enabled for analysing the performance of the supply chain. As an example, the environmental performance of a product can be traced and analysed even on an individual level. This means that not only the performance from the own production of a manufacturer will be accessible, but also the upstream processes that constitute the product value chain and the life cycle performance for the product leaving the manufacturer.

High Frequency and Ultrahigh Frequency Radio Frequency Identification Passive Sensor Transponders for Humidity and Temperature Measurement Within Building Structures

This paper presents the development of passive high frequency (HF) and ultrahigh frequency (UHF) radio frequency identification (RFID) sensor transponders for humidity and temperature monitoring. The transponders use RFID integrated circuits with a digital interface for communicating with a ultralow-power microprocessor. The microprocessor handles the measurement, either by charging sensor and reference capacitors, or by commanding a digital sensor. The read ranges of the sensor nodes are 5 cm and up to 40 cm at HF and UHF, respectively. The sensor nodes are demonstrated in concrete casts, where the HF node provides better than 5%RH-repeatability of the moisture measurements from sensor node to another. At UHF the repeatability is about 15%RH.

UHF RFID based tracking of logs in the forest industry

This paper describes a prototype of a UHF RFID based log marking and tracking system developed for the challenging four-season outdoor conditions in Scandinavia. The RFID system comprises of novel pulping compatible EPC Class 1 Generation 2 transponders, and of robust readers with novel performance boosting features. A wedge-shaped transponder is inserted into the log end with a special tool so that it is protected and held firmly in place by wood during the transportation and processing of timber. A robust EPC-compliant RFID reader featuring an adaptive RF front end was developed for use in a harvesting machine. Readability tests at saw mills with test logs using specially adapted commercial UHF readers show nearly a 100% readability for the transponders inside fresh moist logs.