Doctoral Thesis

3D Printed Microwave Structures

Final Thesis 32.61 MB Summary of Thesis 32.61 MB

Author of thesis: Ing. Jaroslav Zechmeister

Acad. year: 2025/2026

Supervisor: doc. Ing. Jaroslav Láčík, Ph.D.

Reviewers: Ing. Ondřej Franek, Ph.D., prof. Miroslav Joler, Ph.D.

Abstract:

This dissertation focuses on the development of methods for the design and optimization of pixelated microwave structures. A novel optimization algorithm, Binary Ink Stamp Optimization (BISO), was proposed and demonstrated strong performance on benchmark problems as well as in practical antenna and filter designs. A design strategy for SIW horn antennas employing pixelated dielectric loads was introduced and validated through the design of three antennas. An automated procedure for waveguide filter design based on pixelation was developed and applied to two X-band filters. All prototypes were fabricated using 3D printing. The TR method was used to characterize the electromagnetic properties of the 3D-printed materials used for the design of the aforementioned structures.

Keywords:

pixelated microwave structures, SIW horn antennas, waveguide filters, evolutionary algorithms, binary optimization, 3D printing

Date of defence

07.11.2025

Result of the defence

Defended (thesis was successfully defended)

znamkaPznamka

Process of defence

The applicant presented objectives and results of his PhD thesis. Binary ink stamp optimization is the original method to optimize pixelated antennas and waveguides. Performance of the method was demonstrated on the design of several horn antennas and waveguide bandpass filters. Designed antennas and waveguides were experimentally characterized and compared with conventional structures. Results were properly published in recognized journals and conference proceedings. The supervisor and reviewers presented their evaluation. All the evaluations were positive. Reviewers, board members and audience asked questions on dissertation topics; all questions were properly answered.

Language of thesis

English

Faculty

Fakulta elektrotechniky a komunikačních technologií

Department

Department of Radio Electronics

Study programme

Electronics and Communication Technologies (DKC-EKT)

Composition of Committee

prof. Dr. Ing. Zbyněk Raida (předseda)
doc. Ing. Milan Polívka, Ph.D. (člen)
prof. Ing. Miloslav Čapek, Ph.D. (člen)
Ing. Ondřej Franek, Ph.D. (člen)
prof. Miroslav Joler, Ph.D. (člen)

Supervisor’s report
doc. Ing. Jaroslav Láčík, Ph.D.

The dissertation thesis submitted by Jaroslav Zechmeister deals with the development of methods for the design and optimization of pixelated microwave structures.

In my opinion, the main original results of the dissertation thesis are:
- The development of a novel optimization algorithm called Binary ink stamp optimization (BISO) for the design of pixelated microwave structures. A key feature of this algorithm is that it reflects significance of bits during the optimization process.
- The development of a novel design procedure for SIW horn antennas based on pixelated loads. By that procedure, SIW horn antennas with nearly equal HPBWs in the principal planes can be designed. The approach overcomes a limitation in the design of SIW horn antennas.
- A proposal of an automated design procedure based on the pixelation strategy for waveguide microwave filters.

The core of the dissertation thesis is based on two scientific journal papers (IEEE Access, and  IEEE Microwave and Wireless Technology Letters) and two conference papers which also prove its originality. In addition, one manuscript is under review in the scientific journal Microwave and Optical Technology Letters.

Jaroslav was engaged in educational activities at the university as well:
- He supervised 2 bachelor theses focused on pixelated and 3D printed dielectric resonator antennas.
- He contributed to teaching and updating laboratory exercises of courses focused on antennas and microwave techniques.

In my opinion, Jaroslav Zechmeister meets all requirements on a PhD candidate. I therefore fully recommend his dissertation thesis for the defence.

Reviewer’s report
Ing. Ondřej Franek, Ph.D.

viz pdf
File inserted by the reviewer Size
Posudek oponenta [.pdf] 291,65 kB

Reviewer’s report
prof. Miroslav Joler, Ph.D.

viz pdf
File inserted by the reviewer Size
Posudek oponenta [.pdf] 547,68 kB

Responsibility: Mgr. et Mgr. Hana Odstrčilová