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

• Final Report Year: 2012

Final Report Abstract

The present collaborative project is of interdisciplinary nature involving full cycle of design, development and characterization of high frequency material and devices and integration of the material into the devices. Today use of hand held electronic devices is massively growing and driving the trend of miniaturization thus necessitating size reduction and performance enhancement of passive components such as inductors, capacitors which are crucial for high frequency circuits. The operating frequencies of such devices are also steadily increasing typically to GHz range. Novel high frequency magnetic polymer based nanocomposites were prepared by sputtering from metal and polymer. Additionally SiO2 based nanocomposites were also explored. The materials exhibit ferromagnetic resonance frequency well above 1 GHz and promising permeability and quality combined with high electrical resistivity which is essential for prevention of losses due to eddy currents. The experimental work was complimented by extensive modelling. The process proved to be compatible with microelectronics processing which is most important for integration into devices. Both polymer and ceramic based nanocomposites were successfully integrated in to toroidal microinductor. During this project a novel approach for the determination of unknown parameters of soft magnetic materials like Ms, Hk and α was developed and applied to magnetic nanocomposites. Apart from toroidal microinductor more complex component like 3D Thin Film 50:200Ω Guanella-Baluns using optimized 100 Ω transmission line were designed. Using Ansoft HFSS field simulator various balun parameters like coil width, coil height and coiling angel were varied and optimized with the aim of maximizing the bandwidth. Guanella balun with 10 turns having no magnetic core were successfully fabricated.

Publications

• Functional Materials for Microwave Applications. Conference Proceedings GeMic (2008) pp. 205-208
  F. Hettstedt, H. Greve, U. Schürmann, V. Zaporojtchenko, R. Knöchel, F. Faupel, E. Quandt
  
• Functional Polymer Nanocomposites. Polymer & Polymer Composites 16 (8) (2008) pp. 471-482
  F. Faupel, V. Zaporojtchenko, T. Strunskus, H. Greve, U. Schürmann, H. Takele, C. Hanisch, V.S.K Chakravadhanula, N. Ni, A. Gerber, E. Quandt, R. Podschun
  
• Permeameter For The Characterization of Magnetic Thin Films Up To 15 GHz. Proceedings of the 38th European Microwave Conference. (2008), pp. 797-800
  F. Hettstedt, U. Schürmann, R. Knöchel, E. Quandt
  
• Double Coil Permeameter for the Characterization of Magnetic Materials. Conference Proceedings GeMic (2009)
  F. Hettstedt, U. Schürmann, R. Knöchel, E. Quandt
  
• Fabrication of Toroidal Microinductors for RF Applications. IEEE Transactions on Magnetics. 45 (2009) pp. 4770 - 4772
  U. Schürmann, A. Gerber, A. Kulkarni, F. Hettstedt, V. Zaporojtchenko, R. Knöchel, F. Faupel, E. Quandt
  
• Metal-Polymer Nanocomposites for Functional Applications. Advanced Engineering Materials 12 (2010) pp. 1177-1190
  F. Faupel, V. Zaporojtchenko, T. Strunskus, M. Elbahri
  
• Toroid Microinductors Using Segmented Magnetic Cores. Conference Proceedings IMS. (2010) pp. 1348–1351
  F. Hettstedt, U. Schürmann, R. Knöchel, E. Quandt