Magnetic nanocomposites for rf applications in mobile communication

• Applicants: Professor Dr. Franz Faupel; Professor Dr.-Ing. Reinhard Knöchel; Professor Dr.-Ing. Eckhard Quandt
• Subject Area: Synthesis and Properties of Functional Materials
• Term: from 2006 to 2010
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 23262784

This project aims at the development of new high frequency magnetic materials and their use and evaluation in novel high frequency components used mainly in mobile communication electronics. The ongoing demand for miniaturization in mobile electronic devices as well as steadily increasing frequencies of electronic circuits into the GHz range have stimulated the research on high frequency magnetic components. It is well known that a highly permeable material can increase the inductance of an inductor, ideally by a factor of the relative permeability of the material. thus a substantial increase in inductance and hence in the quality factor can be obtained if no extra losses are produced by the magnetic material. The current approaches suffer either from low permeabilities, high conductivity leading to eddy current losses, low ferromagnetic resonance frequencies or from difficulties to align the hard axis in complex geometries necessary for high performance electronic components. Following the route suggested in a recent theoretical paper our approach is based on magnetic nanoparticles in a polymer matrix. If this approach is successful it will allow us to effectively suppress eddy currents, to achieve a perpendicular anisotropy in soft magnetic thin film materials and to obtain very high cut-off frequencies with reasonable high frequency permeabilities.The project includes the preparation of these magnetic materials by vapor phase co- or tandem deposition by the group of Franz Faupel (University of Kiel), who has a long-standig expertise in metal-polymer interfaces and composites. The magnetic as well as high resolution transmission electron microscopy characterization is performed by the group of Eckhard Quandt (Caesar, Bonn), who is an expert in high frequency materials and their incorporation in electronic components. To demonstrate the benefits of these new materials the group of Reinhard Knöchel (University of Kiel), a specialist on high frequency and microwave engineering, will design different electronic components such as inductors an BALUNs which will be fabricated using caesar¿s cleanroom facilities. Their high frequency properties will be characterized by Reinhard Knöchel¿s group which will compare them to own modeling results and to the data achieved with classical state-of-the-art thin film materials.

• DFG Programme: Research Grants