Brno University of Technology

About: Brno University of Technology is a education organization based out in Brno, Czechia. It is known for research contribution in the topics: Fracture mechanics & Filter (video). The organization has 6339 authors who have published 15226 publications receiving 194088 citations. The organization is also known as: Vysoké učení technické v Brně & BUT.

Synthesis and Optimization of Fractional-Order Elements Using a Genetic Algorithm

Abstract: This study proposes a new approach for the optimization of phase and magnitude responses of fractional-order capacitive and inductive elements based on the mixed integer-order genetic algorithm (GA), over a bandwidth of four-decade, and operating up to 1 GHz with a low phase error of approximately ±1°. It provides a phase optimization in the desired bandwidth with minimal branch number and avoids the use of negative component values, and any complex mathematical analysis. Standardized, IEC 60063 compliant commercially available passive component values are used; hence, no correction on passive elements is required. To the best knowledge of the authors, this approach is proposed for the first time in the literature. As validation, we present numerical simulations using MATLAB ® and experimental measurement results, in particular, the Foster-II and Valsa structures with five branches for precise and/or high-frequency applications. Indeed, the results demonstrate excellent performance and significant improvements over the Oustaloup approximation, the Valsa recursive algorithm, and the continued fraction expansion and the adaptability of the GA-based design with five different types of distributed RC/RL network.

High-Gain Dielectric-Loaded Vivaldi Antenna for $K_{a}$ -Band Applications

Abstract: In this letter, a novel concept of a high-gain Vivaldi antenna operating in the $K_{a}$ frequency band is proposed. The antenna is fed by the substrate integrated waveguide. The concept overcomes shortcomings of conventional antipodal Vivaldi antenna using dielectric load with printed metal transition and transverse ripples. The added parts are optimized to obtain a wideband high-gain antenna with low cross polarization. The fabricated antenna shows very good performance over the entire $K_{a}$ band where the measured gain is more than 10.5 dBi.

A Noise Adaptive Fuzzy Equalization Method for Processing Solar Extreme Ultraviolet Images

Abstract: A new image enhancement tool ideally suited for the visualization of fine structures in extreme ultraviolet images of the corona is presented in this paper. The Noise Adaptive Fuzzy Equalization method is particularly suited for the exceptionally high dynamic range images from the Atmospheric Imaging Assembly instrument on the Solar Dynamics Observatory. This method produces artifact-free images and gives significantly better results than methods based on convolution or Fourier transform which are often used for that purpose.