► FlexARTwo – Flexible Active Radar Backscatter Tag in Organic Electronics


Professor Dr.-Ing. Frank Ellinger

Technische Universität Dresden
Institut für Grundlagen der Elektrotechnik und Elektronik
Professur für Schaltungstechnik und Netzwerktheorie

Professor Dr. Karl Leo

Technische Universität Dresden
Institut für Angewandte Physik
Lehrstuhl für Optoelektronik

Professor Dr.-Ing. Martin Vossiek

Friedrich-Alexander-Universität Erlangen-Nürnberg
Department Elektrotechnik-Elektronik-Informationstechnik
Lehrstuhl für Hochfrequenztechnik

Project Summary

FlexART aims at demonstrating the first organic switched injection-locked oscillator (SILO) based active wireless localization tags. The project combines the complementary competences of the groups of Prof. Leo (IAPP with focus on organic materials, semiconductors and device fabrication), Prof. Ellinger (CCN with core competences regarding the characterization, modelling and design of devices and ICs), and Prof. Vossiek (LHFT with expertise in wireless system and radar design).The flexible wireless tags, together with the transmission of radar waves, can be used for the localization of objects up to a 15 m radius. The localization tags can be applied for medical sensors, object tracking in crowded areas and logistics. The tags will have the size of a credit card, will contain novel organic transistors (PBTs), will allow low cost mass fabrication, and will be operated at a few MHz enabling a very good robustness against obstacles in the radar detection path. The SILO topology pioneered by Prof. Vossiek will be employed. Since this system is based on positive feedback, the involved amplifier needs a gain of only slightly above unity to allow a very high sensitivity and the detection of signals down to -60 dBm. The CCN will employ and enhance its long-standing experience in the SILO research to optimize the active IC for the tag. Robust circuit design techniques to mitigate the device variations during bending will be researched. Area-optimized antennas will be designed by LHFT. The complete tag will be fabricated by IAPP on a flexible organic substrate.Based on the deep understanding of organic semiconductors and advanced doping techniques, the IAPP has recently demonstrated a novel kind of organic vertical transistor, which is referred to as permeable base transistor (PBT). The characteristics of the organic PBT resemble those of a bipolar junction transistor and promise very good high-frequency capabilities, better than those of the conventional field-effect based organic transistors. In this project, the semiconductor dopings and geometries of the organic PBTs will be optimized for high-frequencies and thus for the use in the active wireless tags. The evolved PBTs will be characterized and modelled by CCN. A design kit including active and passive devices will be developed to provide an efficient platform for research, circuit design, and system design for the organic tags. FlexART will demonstrate a complete positioning system based on the flexible localization tags. For this purpose, LHFT will develop the required base stations performing techniques for positioning. Algorithms will be researched by LHFT to get maximum positioning accuracy. Effects of bending and imperfection of the organic technologies will be taken into account.The FlexART consortium is very motivated to co-operate with the other projects in the SPP and can offer lectures covering topics from organic materials up to full RF systems to the young researchers.