Research: Acoustics, electromagnetics, waveguide filters and components

Research interest

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

Thesis

1996M.Sc. ThesisFEM of piezoelectric disks / Endelig element modellering av piezoelektriske skiver, Norwegian, (HTML/Postscript)
[Link]
2000Ph.D. ThesisFinite Element Modeling of Ultrasonic Piezoelectric Transducers. Influence of geometry and material parameters on vibration, response functions and radiated field [Additional info]
[Link]

Papers

2001Acta AcusticaResonance Frequency Spectra with Convergence Tests of Piezoceramic Disks using the Finite Element Method, J. Kocbach, P. Lunde and M. Vestrheim, 2001.
[Link]

Presentations

1997Ustaoset 1997Presentation 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]
1998Ustaoset 1998Presentation 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]
1999Matlab Seminar 1999J. 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]
19991999 IEEE Ultrasonics SymposiumJ. 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]
2000Ustaoset 2000Presentation 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]
20022002 IEEE MTT-S International Microwave SymposiumDesign Procedure for Waveguide Filters with Cross-Couplings, Jan Kocbach and Kjetil Folgerø, Nera ASA, Nera Research, N-5020 Bergen
[Link]
20022002 IEEE MTT-S International Microwave SymposiumThe 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]
200333rd European Microwave Conference 2003Yield-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]
2004CNES International Workshop on Microwave FiltersA Low-cost Polymer Waveguide Filter for DVB-RCS Satellite Terminals, Wheatley E., Folgerø K., Kocbach J., Pettersen T., Kopperud A,
[Available on request]
2005Ansoft Converge 2005Use of HFSS as integral part of efficient design environment for waveguide components, J. Kocbach, K. Folgerø
[Link]

Reports

1999ONACS reportJ. 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]
1999FEMP reportJ. 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.

Demonstrations

1999Mode shapes of PZT-5A disksFrequency 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]
1999Mode shapes of BaTiO3 disksFrequency 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]
1999Mode shapes of PbTiO3 disksFrequency 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]
1999PZT5A disk with front layerEigenmodes of a PZT-5A disk with a cork front layer with varying thickness vibrating in vacuum. Made for the IEEE 1999 Ultrasonics Symposium.
[Link]
2000Movie of radiated sound fieldMovie 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]

Blogg About me Research Orienteering Photography Travel Nice places Contact me