

Research: Acoustics, electromagnetics, waveguide filters and components
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Research interest (updated 2005)
I have taken a Ph.D. in hydroacustics, and have worked on electromagnetical
problems at Nera for five years between 2001 and 2006. I am currently
again doing research related to hydroacoustical problems.
My research interests include
- Simulation tools for acustical and electromagnetical structures - with
special emphasis on the Finite Element Method
- Design of waveguide filters and components
- Design of antenna components
- Piezoelectric transducers, including radiation problems
I am especially interested in methods to speed up and automate design processes
by effective use of simulation tools and helper applications.
Publications and Presentations (updated 2005)
Thesis
1996 | M.Sc. Thesis | FEM of piezoelectric disks / Endelig element modellering av piezoelektriske skiver, Norwegian, (HTML/Postscript) [Link] |
2000 | Ph.D. Thesis | Finite Element Modeling of Ultrasonic Piezoelectric Transducers. Influence of geometry and material parameters on vibration, response functions and radiated field [Additional info] [Link] |
Papers
2001 | Acta Acustica | Resonance Frequency Spectra with Convergence Tests of Piezoceramic Disks using the Finite Element Method, J. Kocbach, P. Lunde and M. Vestrheim, 2001. [Link] |
Presentations
1997 | Ustaoset 1997 | Presentation held at 20th Scandinavian Symposium on Physical Acoustics, Ustaoset, 1997. "FEM-ANALYSIS OF PIEZOELECTRIC DISKS - METHOD AND TESTING". This link points to the abstract. [Link] |
1998 | Ustaoset 1998 | Presentation held at 21th Scandinavian Symposium on Physical Acoustics, Ustaoset, 1998. "Piezoceramic disks with a front layer - Comparisons of FEM with experimental data." This link points to the abstract and slides. [Link] |
1999 | Matlab Seminar 1999 | J. Kocbach and M. Kaltenbacher, "ONACS - Object oriented Numerical Analysis of Coupled Systems using MATLAB," in Seminarunterlagen S53, Matlab-Seminar (ARGESIM, c/o EDV-Zentrum TU Wien, Wiedner HStr. 8-10, A-1040 Wien, 1999 [Link] |
1999 | 1999 IEEE Ultrasonics Symposium | J. Kocbach, P. Lunde and M. Vestrheim, "FE Simulations of Piezoceramic Disks with a Front Layer of Varying Thickness," Proc. of 1999 IEEE International Ultrasonics Symposium, 1999. [Link] |
2000 | Ustaoset 2000 | Presentation held at 23rd Scandinavian Symposium on Physical Acoustics, Ustaoset, 2000. " FE Modeling of Piezoceramic Disks including Radiation into a Fluid Medium". This link points to the abstract and slides. [Link] |
2002 | 2002 IEEE MTT-S International Microwave Symposium | Design Procedure for Waveguide Filters with Cross-Couplings, Jan Kocbach and Kjetil Folgerø, Nera ASA, Nera Research, N-5020 Bergen [Link] |
2002 | 2002 IEEE MTT-S International Microwave Symposium | The use of CAD tools in filter design for telecommunication applications (part of Workshop), J. Kocbach & K. Folgerø, Nera ASA, Nera Research, N-5020 Bergen, NORWAY. [Link] |
2003 | 33rd European Microwave Conference 2003 | Yield-driven Design of Direct-coupled Waveguide Filters with Minimum Use of Full Wave EM Solvers, K. Folgerø & J. Kocbach, Nera ASA, Nera Research, N-5020 Bergen, NORWAY. [Available on request] |
2004 | PIERS 2004 Progress In Electromagnetic Research Symposium | Tunable dielectric resonator filters for radio link applications, J. Kocbach, K. Folgerø (NERA Research, Norway), T. Kjøde, M. Jansson (NERA Networks, Norway) [Available on request] |
2004 | CNES International Workshop on Microwave Filters | A Low-cost Polymer Waveguide Filter for DVB-RCS Satellite Terminals, Wheatley E., Folgerø K., Kocbach J., Pettersen T., Kopperud A, [Available on request] |
2005 | Ansoft Converge 2005 | Use of HFSS as integral part of efficient design environment for waveguide components, J. Kocbach, K. Folgerø [Link] |
Reports
1999 | ONACS report | J. Kocbach, "ONACS - Object oriented Numerical Analysis of Coupled Systems using MATLAB," Technical report, Institute of Measurement Technology, Johannes Kepler University Linz, Austria, 1999, 21 p. [Link] |
1999 | FEMP report | J. Kocbach, P. Lunde and M. Vestrheim, "FEMP - Finite Element Modeling of Piezoelectric Structures. Theory and Verification for Piezoceramic Disks," Scientific/Technical report no. 1999-07, Department of Physics, University of Bergen, Bergen, Norway, 1999, 100 p. [Link] |
2001- | Several internal NERA-reports. | No abstracts/titles/articles given.
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Demonstrations
1999 | Mode shapes of PZT-5A disks | Frequency spectrum of PZT-5A disks with varying diameter/thickness ratio. Click on the figure to see how the mode shapes vary with diameter/thickness ratio. Made in conjuntion with the article "Resonance Frequency Spectra with Convergence Tests of Piezoceramic Disks using the Finite Element Method" submitted to Acustica. [Link] |
1999 | Mode shapes of BaTiO3 disks | Frequency spectrum of BaTiO3 disks with varying diameter/thickness ratio. Click on the figure to see how the mode shapes vary with diameter/thickness ratio. Made in conjuntion with the article "Resonance Frequency Spectra with Convergence Tests of Piezoceramic Disks using the Finite Element Method" submitted to Acustica. [Link] |
1999 | Mode shapes of PbTiO3 disks | Frequency spectrum of PbTiO3 disks with varying diameter/thickness ratio. Click on the figure to see how the mode shapes vary with diameter/thickness ratio. Made in conjuntion with the article "Resonance Frequency Spectra with Convergence Tests of Piezoceramic Disks using the Finite Element Method" submitted to Acustica. [Link] |
1999 | PZT5A disk with front layer | Eigenmodes of a PZT-5A disk with a cork front layer with varying thickness vibrating in vacuum. Made for the IEEE 1999 Ultrasonics Symposium. [Link] |
2000 | Movie of radiated sound field | Movie of sound field radiated from a PZT-5A disk with diameter/thickness ratio of 5 for some selected modes. Made for the Ustaoset-2000 meeting. See abstract/slides for further explanations. [Link] |
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