Change search
ReferencesLink to record
Permanent link

Direct link
Low-power humidity sensor for RFID applications
Show others and affiliations
2008 (English)In: 4M2008 Conference, Cardiff, UK, 2008Conference paper (Refereed)
Abstract [en]

Wireless sensors incorporated in RFID systems are important in several industrial, consumer and logisticsapplications. By extending RFID tags to sensing applications, the products become smarter. Application areas forthese smart tags include; health care (verification of the environmental conditions during transport or in storage of e.g.diapers, bandages, etc.), food monitoring (food quality during transport, storage and sales) and construction industry(e.g. building material).In this paper, a small, very low power and low cost humidity sensor tailor made for passive RFID applications ispresented. The sensor consists of a glass chip substrate with a sub-micron interdigitated gold electrode structurecovered with a humidity sensitive polyimide layer. The humidity absorbed by the sensing layer is measuredcapacitively. Finite element modeling and analytic calculations were used to determine the design of the interdigitatedelectrodes and the optimal thickness of the polyimide layer. A read-out electronics circuit was designed and used toevaluate the sensor. Sensors were fabricated and calibrations have been made to verify their function. The sensorresponse was close to linear from below 20 to above 90 %RH and its response time was proven to be at least as shortas that of the climate chamber, namely 0.1 %RH/s. The concept can easily be adapted to measure a range of otherparameters such as temperature or the presence of certain substances.

Place, publisher, year, edition, pages
Keyword [en]
humidity sensor, passive RFID tag, e-beam lithography, nanoimprint lithography (NIL)
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
URN: urn:nbn:se:kth:diva-91789OAI: diva2:784932
4M2008 Conference, Cardiff, UK

QC 20150429

Available from: 2015-01-31 Created: 2012-03-20 Last updated: 2015-04-29Bibliographically approved

Open Access in DiVA

No full text

Other links


Search in DiVA

By author/editor
Haasl, Sjoerd
Electrical Engineering, Electronic Engineering, Information Engineering

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 12 hits
ReferencesLink to record
Permanent link

Direct link