Profile

Jméno: 
Miloslav Čapek
Místnost: 
B2-634
Telefon: 
(+420)777 899 512
E-mail: 
miloslav.capek(at)fel.cvut.cz
Další informace: 
ORCID: 0000-0002-7442-889X,     ResearcherID: H-6674-2014,     ResearchGate

Degrees

 

 

Research interests

My scientific interests mainly cover electromagnetics and small antenna theory. These two areas are mutually interconnected and nowadays often accompanied by utilization and further advancement of numerous computational methods and techniques. The original motivation of my work can be summarized to a relatively simple question: “What antenna is the best one for a given application?” To address this question completely, the complete  understanding of physical phenomena underlying the radiation mechanism is needed.

The theoretical findings as well as practical implementations can be used not only in small antenna design, but also in emerging technologies like nano- and optical antennas, reflect arrays or superbackscaterring arrays. Selected topics actually solved within our group are listed below:

  • (Electrically small) antennas (Source concept: modal and structural decomposition of small radiating bodies and their optimization, feeding synthesis, optimal antennas),
    The Source Concept represents a promising framework providing a unified theory of the evaluation, decomposition and manipulation of electromagnetic currents in ways as yet imagined. It is a mixture of powerful techniques, both analytical and numerical, together with the idea that an electromagnetic current can be substituted into any expression relevant to small antenna design. Although the Source Concept turned out to be instructive for small antennas, it is thoroughly applicable for radiators of any electrical size and shape. The Source Concept deals with two pivotal questions:
    • Which geometrical shape of the radiator and which material distribution are optimal in terms of a selected trade-off between crucial parameters? ˆ
    • Where the radiator should be fed for optimal performance and how should the matching circuit be designed?
     
    Figure: Source Concept presents promising framework for small antennas design.

     
  • Electromagnetic theory (Stored electromagnetic energy, Q factor),

    A consistent definition of stored electromagnetic energy for non-stationary fields is one of the last fundamental and still unsolved problems of classical electrodynamics. One of the key issues is the potentially infinite total energy within a time-harmonic steady state. The definition of the stored energy is encumbered with an ill-defined separation of the total energy into radiated energy and stored energy, where it is assumed that the bearer of the infinity is the radiation. The main concern lies in the investigation of the radiation mechanism and subtraction of the energy associated with radiation.

    Figure: Sketch of novel method for evaluation of stored energy in time domain.
     
  • Characteristic modes theory,
    The theory of characteristic modes became very popular in recent years as it constitutes a general approach to study arbitrarily shaped antennas and scatterers without prior knowledge of the feeding. In its original form, the characteristic decomposition assumes perfectly electric conducting bodies in vacuum. An investigated radiator is then transformed into the impedance operator represented by a matrix of finite extend. Generalized eigenvalue problem is then established based on the real and the imaginary part of the impedance operator. Resulting basis of characteristic currents has very special properties that will be recalled during the lecture. Since no feeding in considered, all attention is focused only on the geometry and its effects on radiation properties. In order to feed the selected set of modes, the position, amplitude and phase of the feeding need to be determined ex post.
    Figure: One of the first five characteristic modes (randomly selected) of randomly generated polygon (daily updated and powered by AToM :) ).
     
  • MATLAB (mainly development of the AToM package)

     

    The last five years have allowed the capabilities of the Source Concept to be recognized and software tools associated with its implementation have begun to appear. To support this common effort and to accelerate the development of the in-house tool TCMapp, a new project, founded by the Technology Agency of the Czech Republic, started in July 2014. An important part of the project is called the Antenna Toolbox for Matlab (AToM). The AToM package aggregates all present scientific know-how of the Source Concept and it will remain in the ownership of Czech Technical University and Brno university of technology. The AToM is written entirely in Matlab, so the user will enjoy its semi-open architecture and friendly operation through GUI or direct access to low level functions. Main simulation core is based on Method of moments, both for 3D wire and planar structures. Together with modal decomposition (Characteristic modes), the source concept, feeding synthesis and powerful optimization (FOPS optimizer), it will present unique tool for syntesis of antennas.

     
  • Single-criteria and multi-criteria (heuristic) optimization,

    Many ingenious techniques have recently been adopted to approach the antenna synthesis as closely as possible. Single- and multi-objective optimization algorithms have proved themselves to be essential tools, in particular the convex optimization and heuristic optimization techniques which can be advantageously combined with the physical machinery introduced above.

    Figure: Multicriteria optimization of the directivity and the quality factor of 4 dipoles separated by distances s and h.The Pareto fronts significantly depends on limits of s and h.
     
  • Fractal geometry (and related small antennas).

    Once discovered, the fractal geometry have been immediately recognized as a fascinating branch of mathematics with many potential applications across the engineering science. This is the case of electromagnetic field theory as well. For instance, the fractal shapes are promising candidates for electrically small antennas. However, many issues needs to be solved and deeper theoretical understanding must be achieved together with discovery of new (ideally) lossless materials.

    Figure: Initial triangle and three affine transformations that together form an Iterated Function System (IFS) of Sierpinski fractal triangle.
 
- for available topics of final projects (individual projects, graduate theses, doctoral dissertations), see HERE
 

Selected recent presentations

(Note: presentations denoted by symbol + contain movable TikZ content - it is neccessary to download the presentation and open it in Adobe Reader to see the movies.)

 

 

Teaching

 
  • SS2016/2017: A0B17MTB (--)
  • SS2015/2016: A0B17MTB (1.060), 3 par.
  • WS2015/2016: A0B17MTB (1.028), 3 par.
  • SS2014/2015: A0B17MTB (1.050), 3 par.
  • WS2014/2015: A0B17MTB (1.139), 2 par.
  • SS2013/2014: A0B17MTB (1.053), 4 par.
  • WS2013/2014: A1B17EMP (1.111)
  • WS2012/2013: A1B17EMP (1.042)
  • SS2011/2012: A2B99MAA ()
  • WS2011/2012: A1B17EMP (1.067), Matlab course (-)
  • SS2010/2011: A2B99MAA (1.240), A2M17AEK (-)
  • WS2010/2011: A1B17EMP (1.095)
  • SS2009/2010: A2B17EPV (1.190), A2B99MAA (1.670)
 
MATLAB course (A0B17MTB)
 

Students

Current students:

  1. Ing. Michal Mašek, Ph.D. thesis (Co-supervisor): Charakteristické mody malých zářičů a jejich interakce s elektricky velkými vodivými objekty
  2. Ing. Vít Losenický, Ph.D. thesis (Supervisor): Theory of characteristic modes and its use for analysis and synthesis of small radiating structures

List of all students, who successfully defended their theses. Following information are provided: kind of work, name of work, year of defence, proposed classification/ oponent's classification, name of oponent // final classification, awards etc.

Former students:

  1. Bc. Jan Vlk, Diploma thesis, Návrh a realizace elektricky malé antény (Design of Electrically Small Antenna),
    2012, A / A, prof. Raida (Brno University of Technology) // A
    IEEE-MTT prize for excellent Diploma thesis
  2. Ing. Pavel Koška, Diploma thesis, Hybrid Nelder-Mead a rojové optimalizace (Hybrid Nelder-Mead - Particle Swarm Optimization),
    2014, A / A, prof. Raida (Brno University of Technology) // A
    Dean's prize for excellent Diploma thesis
  3. Bc. Vojtěch Závada, Diploma thesis, Numerická analýza vyzařovací úlohy elektricky zmenšené smyčky (Energetic Functional of U-notched Loop Antenna),
    2014, B / A, prof. Raida (Brno University of Technology) // A
    Dean's prize for excellent Diploma thesis
  4. Bc. Vít Losenický, Diploma thesis: Characteristic mode decomposition of a spherical shell
    2016, A / A, prof. Raida (Brno University of Technology) // A
    1st place at Poster student conference, session "C - Communication", Dean's prize for excellent Diploma thesis
  5. Bc. Ondřej Krátký, Diploma Thesis (Co-supervisor, Supervisor - doc. Jelínek): Polarizability of electrically small perfectly conducting scatterers
    2016, A (doc. Jelínek, supervisor) // A, Dr. Hudlička
    (Czech metrology institute) // A
    IEEE MTT Czech chapter's award, 3rd place (2016)
  6. Martin Štrambach, Bachelor Thesis: Triangulation of planar objects and its implementation into the AToM package
    2017, A / A, prof. Schenk (Università della Svizzera Italiana) // A

For available topics of final projects, see HERE.

Interships

  • Lund University, 6-months stay, September 2016 - February 2017
  • Lund University, 2-weeks intership, November 2015
  • KU Leuven, 2-weeks intership, August-September 2015
  • KU Leuven, 1-month intership, August-September 2014
  • KU Leuven, 3-weeks intership, September 2013
  • KU Leuven, 1-week intership, January 2013

Research projects

Publications

(Disclaimer: please, be always careful when copying following references without awareness of this profile's owner - the references probably contain some typos that can be transferred into your documents or profiles.)

Journal papers:

  1. Capek, M., Gustafsson, M., Schab, K.: Minimization of Antenna Quality Factor, IEEE Transactions on Antennas and Propagation, Vol. 65, No. 8, pp. 4115-4123, Aug. 2017.
  2. Capek, M., Losenicky, V., Jelinek, L., Gustafsson M.: Validating the Characteristic Modes Solvers, IEEE Transactions on Antennas and Propagation, Vol. 65, No. 8, pp. 4134--4145, Aug. 2017.
  3. Jelinek, L., Kratky, O., Capek, M.: An Evaluation of Polarizability Tensors of Arbitrarily Shaped Highly Conducting Bodies, IET Microwaves, Antennas and Propagation, Vol. 11, No. 6, pp. 852-858, May 2017.
  4. Capek, M., Hazdra, P., Masek, M., Losenicky, L.: Analytical Representation of Characteristic Modes Decomposition, IEEE Transactions on Antennas and Propagation, Vol. 65, No. 2, pp. 713-720, Feb. 2017.
  5. Jelinek, L., Capek, M.: Optimal Currents on Arbitrarily Shaped Surfaces, IEEE Transactions on Antennas and Propagation, Vol. 65, No. 1, pp. 329-341, Jan. 2017.
  6. Capek, M., Jelinek, L.: Optimal Composition of Modal Currents For Minimal Quality Factor Q, IEEE Transactions on Antennas and Propagation, Vol. 64, No. 12, pp. 5230-5242, Dec. 2016.
  7. Capek, M., Jelinek, L., Vandenbosch, G. A. E.: Stored Electromagnetic Energy and Quality Factor of Radiating Structures, Proceedings of Royal Society A, Vol. 472, No. 2188, pp. 1-16, April 2016.
  8. Hazdra, P., Capek, M., Masek, M., Lonsky, T.: On Antenna Parameters Inferable from Sources, Radioengineering (Feature Article), Vol. 2016, No. 1, pp. 12-17, April 2016.
  9. Capek, M., Jelinek, L.: Comments on “On Stored Energies and Radiation Q”, IEEE Transactions on Antennas and Propagation, Vol. 64, No. 10, pp. 4575-4576, Oct. 2016.
  10. Capek, M., Jelinek, L., Hazdra, P.: On the Functional Relation of Quality Factor and Fractional Bandwidth. IEEE Transactions on Antennas and Propagation, Vol. 63, No. 6, pp. 2787-2790, June 2015.
  11. Jelinek, L., Capek, M., Hazdra, P., Eichler, J.: An Analytical Evaluation of The Quality Factor Qz for Dominant Spherical Modes, IET Microwaves, Antennas and Propagation, Vol. 9, No. 10, pp. 1096-1103, 2015.
  12. Capek, M., Eichler, J., Hazdra, P.: Evaluating of Radiation Efficiency from Characteristic Currents, IET Microwaves, Antennas and Propagation, Vol. 9, No. 1, pp. 10-15, 2015.
  13. Hazdra, P., Capek, M., Eichler, J., Mazanek, M.: The Radiation Q-Factor of a Horizontal λ/2 Dipole Above Ground Plane, IEEE Antennas and Wireless Propagation Letters, Vol. 13, pp. 1073-1075, 2014.
  14. Eichler, J., Hazdra, P., Capek, M.: Aspects of Mesh Generation for Characteristic Mode Analysis. IEEE Antennas and Propagation Magazine, Vol. 56, No. 6, pp. 172-183, June 2014.
  15. Capek, M., Jelinek, L., Hazdra, P., Eichler, J.: The Measurable Q Factor and Observable Energies of Radiating Structures. IEEE Transactions on Antennas and Propagation, Vol. 62, No. 1, pp. 311-318, Jan. 2014.
  16. Hazdra, P., Capek, M., Eichler, J.: Comments to “Reactive Energies, Impedance, and Q Factor of Radiating Structures” by G. Vandenbosch. IEEE Transactions on Antennas and Propagation, Vol. 61, No. 12, pp. 6266-6267, Dec. 2013.
  17. Capek, M., Hamouz, P., Hazdra, P., Eichler, J.: Implementation of the Theory of Characteristic Modes in MATLAB. IEEE Antennas and Propagation Magazine, Vol. 55, No. 2, pp. 176-189, April 2013.
  18. Capek, M., Hazdra, P., Eichler, J.: A Method For the Evaluation of Modal Radiation Q Based on Modal Approach. IEEE Transactions on Antennas and Propagation, Vol. 60, No. 10, pp. 4556-4567, Oct. 2012.
  19. Eichler, J., Hazdra, P., Capek, M., Mazanek, M.: Modal Resonant Frequencies and Radiation Quality Factors of Microstrip Antennas. International Journal of Antennas and Propagation, Vol. 2012, pp. 1-9, 2012.
  20. Eichler, J., Hazdra, P., Capek, M., Korinek, T., Hamouz, P.: Design of a Dual Band Orthogonally Polarized L-probe Fed Fractal Patch Antenna using Modal Methods. IEEE Antennas and Wireless Propagation Letters, Vol. 10, pp. 1389-1392, 2011.
  21. Hazdra, P., Capek, M., Eichler, J.: Radiation Q-factors of Thin-Wire Dipole Arrangements. IEEE Antennas and Wireless Propagation Letters, Vol. 10, pp. 556-560, 2011.
  22. Capek, M., Hazdra, P., Hamouz, P., Eichler, J.: A Method For Tracking Characteristic Numbers and Vectors. Progress In Electromagnetics Research B, Vol. 33, pp. 115-134, 2011.
  23. Capek, M., Hazdra, P., Hamouz, P., Mazanek, M.: Software tools for efficient generation, modeling and optimisation of fractal radiating structures. IET Microwaves, Antennas and Propagation, Vol. 5, pp. 1002-1007, 2011.

Manuscripts (in review / arxiv):

  1. Schab, K., Jelinek, L., Capek, M.: Recoverable Energy of Dissipative Electromagnetic Systems, pp. 1-5, 2017. [Online]: https://arxiv.org/abs/1701.06313 (unpublished manuscript).
  2. Capek, M., Jelinek, L.: Various Interpretations of the Stored and the Radiated Energy Density, pp. 1-5, 2015. [Online]: https://arxiv.org/abs/1503.06752 (unpublished manuscript).
  3. Schab, K., Jelinek, L., Capek, M., Ehrenborg, C., Tayli, D., Vandenbosch, G.A.E., Gustafsson, M.: Energy Stored by Radiating Systems, pp. 1-21, 2015. [Online]: https://arxiv.org/abs/1705.07942 (unpublished manuscript).

Conference papers:

  1. Gustafsson, M., Capek, M., Schab, K.: Fundamental Limitations on the Quality Factor and Related Problems for Small Antennas, IEEE APS/USNC-URSI, San Diego, USA, 2017.
  2. Capek, M., Losenicky, V., Jelinek, L., Gustafsson, M., Tayli, D.: Numerical Benchmark Based on Characteristic Modes of a Spherical Shell, IEEE APS/USNC-URSI, San Diego, USA, 2017.
  3. Jelinek, L, Schab, K., Capek, M.: Minimum Energy Storage in Dissipative Electromagnetic Systems, IEEE APS/USNC-URSI, San Diego, USA, 2017.
  4. Jelinek, L., Kratky, O., Capek, M.: Polarizability Tensors of Highly Conductive Bodies, IEEE APS/USNC-URSI, San Diego, USA, 2017.
  5. Masek, M., Capek, M., Hazdra, P., Dai, Q. I., Chew, W. C.: Characteristic Modes of Electrically Small Antennas in Presence of Electrically Large Platforms, PIERS, St. Petersburg, Russia, 2017.
  6. Gustafsson, M., Capek, M., Schab, K.: Minimum Q-factors for Antennas, EuCAP 2017, Paris, France, 2017.
  7. Capek, M., Jelinek, L., Kadlec, P., Štrambach, M.: Excitation of Optimal and Suboptimal Currents, EuCAP 2017, Paris, France, 2017.
  8. Capek, M., Jelinek, L.: Optimal Composition of Characteristic Modes For Minimal Quality Factor Q, IEEE APS/USNC-URSI, Fajardo, Puerto Rico, 2016.
  9. Jelinek, L., Capek, M.: Optimal Currents in the Characteristic Modes Basis, IEEE APS/USNC-URSI, Fajardo, Puerto Rico, 2016.
  10. Capek, M., Masek, M., Hazdra, P.: Some Numerical Aspects of Characteristic Mode Decomposition, EuCAP 2016, Davos, Switzerland, 2016.
  11. Hazdra, P., Capek, M., Lonsky, T.: Bandwidth Optimization of Linear Arrays Above Ground, EuCAP 2016, Davos, Switzerland, 2016.
  12. Capek, M., Jelinek, L.: On the Properties of Stored Electromagnetic Energy, PIERS 2015, Prague, Czech Republic, 2015.
  13. Jelínek, L., Capek, M.: The Quality Factor Qz of the Combined TE10 / TM10 Spherical Mode,  IEEE APS/USNC-URSI, Vancouver, Canada, 2015.
  14. Capek, M., Jelinek, L.: The Relation Between Fractional Bandwidth and Q Factor, IEEE APS/USNC-URSI, Vancouver, Canada, 2015.
  15. Capek, M., Jelinek, L., Vandenbosch, G. A. E., Hazdra, P.: Time Domain Scheme for Stored Energy Evaluation, IEEE APS/USNC-URSI, Vancouver, Canada, 2015.
  16. Jelinek, L., Capek, M.: On the Stored and Radiated Energy Density, EuCAP 2015, Lisbon, Portugal, 2015.
  17. Capek, M., Hazdra, P., Mazanek, M., Raida, Z., Rymus, J.: The Antenna Toolbox for Matlab (AToM), EuCAP 2015, Lisbon, Portugal, 2015.
  18. Capek, M., Jelinek, L., Vandenbosch, G.A.E., Hazdra, P.: A Novel Scheme for Stored Energy Evaluation, EuCAP 2015, Lisbon, Portugal, 2015.
  19. Jelinek, L., Capek, M., Hazdra, P., Eichler, J.: Lower Bounds of the Quality Factor Qz, IEEE APS/USNC-URSI, Memfis, USA, 2014.
  20. Capek, M., Jelinek, L., Hazdra, P., Eichler, J.: The Source Definition of The Quality Factor Qz, IEEE APS/USNC-URSI, Memfis, USA, 2014.
  21. Capek, M., Eichler, J., Hazdra, P., Mazanek, M.: A Method for the Evaluation of Radiation Efficiency Based on Modal Approach, EuCAP 2014, The Hague, The Netherlands, 2014.
  22. Kozak, F., Capek, M., Jenik, V., Hudec, P., Skvor, Z.: Simulation of Electromagnetic Field of a Fast Moving Target Close to Antennas, EuCAP 2013, Gothenburg, Sweden, 2013.
  23. Capek, M., Hazdra, P., Eichler, J., Hamouz, P., Mazanek, M.: Acceleration Techniques in Matlab for EM Community, EuCAP 2013, Gothenburg, Sweden, 2013.
  24. Hazdra, P., Capek, M., Eichler, J., Korinek, T., Mazanek, M.: On the modal resonant properties of microstrip antennas, EuCAP 2012, Prague, Czech Republic, 2012.
  25. Capek, M., Hazdra, P., Eichler, J., Hamouz, P., Mazanek, M., Sobotiková, V.: The Evaluation of Total Radiation Q Based on Modal Approach, EuCAP 2012, Prague, Czech Republic, 2012.
  26. Hazdra, P., Eichler, J., Capek, M., Hamouz, P., Korinek, T.: Small Dual-band Fractal Antenna with Orthogonal Polarizations, EuCAP 2011, Rome, Italy, 2011.
  27. Hazdra, P., Capek, M., Eichler, J., Hamouz, P., Mazanek, M.: Radiation Q of dipole modal currents, EuCAP 2011, Rome, Italy, 2011.
  28. Hamouz, P., Hazdra, P., Polivka, M., Capek, M., Mazanek, M.: Radiation Efficiency and Q Factor Study of Franklin Antenna Using the Theory of Characteristc Modes, EuCAP 2011, Rome, Italy, 2011.
  29. Hazdra, P., Capek, M., Hamouz, P., Mazanek, M.: Advanced Modal Techniques for Microstrip Patch Antenna Analysis, ICECom 2010, Zagreb: KoREMA, Croatia, 2010.
  30. Capek, M., Hazdra, P.: Design of IFS Patch Antenna Using Particle Swarm Optimization, EuCAP 2010, Barcelona, Spain, 2010.
  31. Hazdra, P., Capek, M., Kracek, J.: Optimization Tool for Fractal Patches Based on the IFS Algorithm, EuCAP 2009, Berlin, Germany, 2009.
  32. Capek, M.: PSO Optimalization of IFS Fractal Patch Antennas. In Poster 2009. Praha: České vysoké učení technické v Praze, 2009.
  33. Hazdra, P., Capek, M.: IFS Tool for Fractal Microstrip Patch Antenna Analysis, COMITE 2008, Brno, Czech Republic, 2008.
  34. Capek, M., Hazdra, P.: PSO optimalizace v MATLABU. In Technical Computing Prague 2008, Prague, Czech Republic, 2008.

Books

All books, that are available on view.

/Edited 14. 9. 2017, MC/