One focus area for our research is related to the hardware for cellular electronics, including the radio front end, the digital base band, as well as the mixed-signal area. Circuits are designed in the latest CMOS technologies, fabricated in well-established foundries worldwide and characterized in detail at our measurement labs. Our interest natrually covers the established frequencies up to 3.5 GHz, but we also consider design and applications at the higher frequencies, including 60 GHz and above. One particular aspect is related to the system design where we not only consider the individual components, but rather the complete system. The area of research is performed in close collaboration with our industrial partners.
We develop devices and circuits in emerging technologies. III-V MOSFETs are implemented in the form of nanowires where cylindrical gates are used to improve the electrostatic control and improved materials properties are used to increase the drive current. We consider the RF-properties of the devices and fabricate small-scale radio circuits. Tunneling devices are used to implement mm-wave wavelet generators forming short RF-bursts. These are used for short-range communication applications. The research includes efforts in materials science with detailed studies of the materials properties.
In some applications like pace-makers and other medical implants low power consumption is of utmost importance, since the battery must both be small and last a long time. We therefore perform research pushing the boundaries of circuit power consumption. For high integration we use CMOS technology and reduce the power consumption through circuit design techniques. For example we operate the MOS transistors in the subthreshold region. Our major effort in the area is currently to design an ultra low power radio. The full system is designed, including antennas, high frequency circuits, analog to digital converters, digital baseband, analog decoding, and radio algorithms. Power reduction is addressed in all different parts as well as on system level.
Information Retrieval Systems
In this area KnowLib conduct research in the design, building, use and interoperability of information systems, like semantic-based topic-specific search engines, specifically in the web environment. Focused Web-crawling is an integral component of topic-specific search engines, capable of generating topic-specific databases of Web-pages. We study techniques for automated subject classification like thesauri based string matching as well as machine learning methods (eg SVM). Knowledge discovery and knowledge organization systems are also explored in the digital library context.