BACHOREC, P. Jednobodově napájená kruhově polarizovaná anténní řada pro BLE lokalizaci [online]. Brno: Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií. 2025.
The project was focused on the design of circularly polarized antenna arrays for the localization by the Bluetooth Channel Sounding technology. The project was solved in cooperation with NXP Semiconductors. The project was aimed to design 2x2 arrays of patches with a single-point excitation. The arrays were completed by a switch and an Arduino header to control the array by the KW47 microcontroller. The array was fully implemented, measured and tested in real-life conditions (distance measurement in an underground garage). Hence, all the objectives were met. Unfortunately, more time than expected was spent on simulations and optimizations of separate antenna elements. Therefore, less time was available to complete antenna elements by the feeding network, to implement the whole array and to compose the final report. The student spent a huge amount of time working on the project, and each step of solution discussed regularly. Despite the hard work, enthusiasm and high activity, quality of the output is lower than expected (due to the missing time). And the output was negatively influenced by the last-moment change of technology as well (FR4 stack-up was replaced by ARLON) the student was not blame for.
The submitted bachelor thesis presents the design, simulation, fabrication, and measurement of a circularly polarized antenna array intended for localization applications. However, the work lacks a clear and structured introduction that outlines the intended use of the antenna, the corresponding performance requirements, and quantifiable criteria for evaluating the final prototype. Additionally, a review of relevant state-of-the-art solutions is notably missing. The design of the antenna array is done by HFSS simulations and optimizations. While most plots are reasonably clear, the radiation pattern diagrams require improved labeling of the gain axis. Some of the S11 and axial ratio plots suggest there is insufficient frequency resolution of the data. I would also recommend consolidating multiple result curves into single plots to enhance clarity and compactness. Furthermore, the optimization parameters are presented only in tabular form; incorporating these as dimensions directly into the antenna drawings would significantly improve comprehensibility. From a formal perspective, the thesis suffers from poor English, which at times hinders understanding. Figure captions are insufficiently descriptive, and the use of VNA screenshots with small, unreadable fonts rather than exporting and presenting the data properly is considered poor practice. The fabricated prototype shows limited agreement with simulation results, and the localization accuracy appears to be suboptimal. Although the author acknowledges that certain mistakes occurred during the development process, there is a lack of reflection on these issues or discussion of how they could have been avoided.
eVSKP id 167817