ŠTUMPF, M. Pulzní elektromagnetické záření štěrbinových antén [online]. Brno: Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií. 2011.
Úvod. Předložená disertační práce je zaměřena na pulzní elektromagnetické záření štěrbinových antén. Téma práce je aktuální. V současné době analýza v časové oblasti získáva čím dál tím větší pozornost. Originalita řešení. Původním příspěvkem předložené práce je odvození vztahů v uzavřeném tvaru v časové oblasti popisující elektromagnetické záření dvourozměrných štěrbinových antén různě konfigurovaných. Pro odvození byla použita Carnigard-DeHoopova metoda. Dle mého názoru využití této metody pro analýzu vybraných anténních struktur je velmi originální. Obdržené výsledky mohou být použity pro efektivní návrh anténních polí buzených pulsními signály. Publikace. Jádro dizertační práce bylo publikováno v časopiseckých článcích (Radio Science, IEEE Transactions on Antennas and Propagation) a v jednom konferenčním článku. Myslím, že je to dost pro úspěšné absolvování Ph.D. studia. Závěr. Martin Štumpf během řešení své práce pracoval svědomitě a samostatně. Dokázal, že je schopen řešit i velmi náročné vědecké úkoly. Myslím, že jeho práce je na velmi vysoké úrovni. Práci doporučuji k obhajobě.
Review of the Doctoral Thesis: Pulsed Electromagnetic Field Radiation from Slot Antennas, submitted by Ing. Martin Stumpf Reviewer: Prof. dr. ir. Guy A. E. Vandenbosch ESAT-TELEMIC, K.U.Leuven Kasteelpark Arenberg 10 B-3001 Leuven, Belgium Tel. 32-16-32.11.10, email: Guy.Vandenbosch@esat.kuleuven.be 1. Topic: The main topic of the thesis is the derivation of closed-form solutions describing the electromagnetic fields in time domain for a series of well-chosen canonical radiation topologies involving an infinitely long slot in a conducting plane. This topic is certainly appropriate and up to date from the viewpoint of the present level of knowledge. Time domain analysis is a topic which is coming more and more into the picture the latest few years. 2. Originality: The thesis is based on a combination of several techniques known in literature to analyze the structures: Laplace transforms to handle time dependency (going to s-domain), Fourier transforms to handle the dependency transversal to the slot (going to p-domain) (although this is named differently in the thesis). The combination of these techniques allows to obtain closed form expressions for the fields in the ps-domain. Using the Cagniard – De Hoop technique, these expressions deliver closed form expressions in the space - time domain. As far as I know, applying this procedure to the chosen canonical topologies is indeed very original. 3. Publications: According to the information given, the work is published or accepted for publication in three journal papers and at two conferences. This is certainly above the threshold for a Ph.D.. 4. Erudition: based on the nature and quality of the text, the publications, I indeed can conclude that he is a person with outstanding research erudition. 5. Quality of the text: The text is well-written and clearly structured. The English did not pose any problem for me. In my view the Ph.D. text is of the right concision level for this type of text. I would suggest however to increase both the size of the Ph.D. book and the font of the text. One disadvantage of growing “wiser”, is that it goes along with growing “older”, which means that very small fonts start to be a bit of a problem sometimes. 6. Suggestions: I do have some advice. What I was a bit missing is an independent validation, either by comparison with another technique, a commercial solver, or even with measurements (but I guess that will be quite difficult), or at least a discussion on this. I also would suggest to give a more in depth view in the conclusion section on how to proceed from the results obtained. In my view, the candidate is not far from a much more general implementation involving arbitrary multilayered structures. Also, how to handle slots of finite length could be discussed a bit in the conclusions section. In my view, based on the previous, the thesis meets the standard generally required for the awarding of an academic degree. Leuven, April 27, 2011 Prof. dr. ir. Guy A. E. Vandenbosch
Review of a dissertation thesis Pulsed Electromagnetic Field Radiation from Slot Antennas submitted by Ing. Martin Štumpf Ing Martin Štumpf has selected a topic that undisputably fits well into the field of Electronics and Communication Technology. The topic is not only up to date, but really can bear the adjective state-of-the-art. From the formal point of view, this work clearly exceeds the average. The author has produced a text that is as easy to read as possible (taking into account the topic that is complicated itself). The figures as well as the text must have been prepared carefully and are close to perfect. The text is divided into 10 chapters, with some derivations condensed into appendices. Chapter 1 serves as an introduction to the topic. Typographic conventions used in following chapters as well as some mathematical background are mentioned in its second part. Chapter 2 brings a collection of electromagnetic field equations essential for the rest of dissertation. Chapters 3 to 9 contain the real nucleus of the work. Each of these chapters is written as an autonomous piece of text. Each chapter can be read separately. Despite of the fact that this description brings some equations more times, I find it suited well for this work. Chapter 10 makes a short summary at the end of the dissertation. The original part of the work is found in chapters 3 to 9. Closed form equations in time-domain are derived for several radiator types, including slots covered by a dielectric layer. The importance of direct time-domain analysis is commonly overseen. Most works use harmonic field instead of that. Such an approximation is of limited validity only. New technologies such as UWB applications are demanding for better electromagnetic field descriptions. Therefore, the results presented in the dissertation are not only new, but also important. I have but a few comments on the work: • I would personally prefer enlarging paper format as well as font, up to standard A4 size. The work is rich in equations with subscripts, small size may bother the reader. • Mentioning J. C. Maxwell with equation (2.1) would have helped me to understand faster. • Figure 6.4 (page 47) to 6.11 seem to use only a part of the color scale, such a compression reduces the information contained. Despite of these comments, none of which I find really important, I conclude that the thesis of Ing. Martin Štumpf clearly surpasses requirements for a dissertation. In my opinion this work is excellent. The author has clearly demonstrated his ability to perform state-of-the-art research as well as his ability to formulate and publish his results. The dissertation core has been published properly. Therefore, I an pleased to serve as a reviewer and suggest that Ing. Milan Štumpf receives the PhD. degree. Prague, April 17, 2011 Prof. Ing. Zbyněk Škvor, CSc.
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