Z. Lukes

Design and optimization of periodic structures for simultaneous EBG and AMC operation

The paper focuses on design and optimization of metallo-dielectric periodic structures with simultaneous electromagnetic band gap (EBG) and artificial magnetic conductor (AMC) behavior in the required frequency band. Three variants of mushroom structures were studied to fulfill the requirements: the two-layer one with simple square metallic patch, the two-layer one with metallic patch of complex shape and the three-layer one with simple square metallic patch at the top and the bottom layer. The structures were tuned using particle swarm optimization (PSO) algorithm implemented in Matlab in connection with CST Microwave Studio (CST MWS) for full-wave dispersion diagram and reflection phase diagram computation. The obtained results were verified by Ansofts High Frequency Structure Simulator (HFSS).

Signal processing techniques for stabilization of marching-on-in-time method

This paper deals with the stabilization of MOT method by digital filters. We propose how to design such a filter with using the optimization techniques. The proposed procedure takes into account the important part of the spectrum of excitation signal, so the designed filter do not degrade the accuracy of MOT method. Further, the issue of successful stabilization of MOT method by set of filters is discussed.

Multi-Objective Synthesis of Multiband Planar Antennas in Time Domain

The paper is focused on the multi-objective optimization of multiband antennas. The prescribed frequency response of the reflection coefficient at the antenna input, the maximum gain in the operation bands and the minimum volume of the antenna are the objectives considered in the optimization procedure. Since the wide-band analysis of the multiband antenna is performed in the time domain, the objective functions are composed without frequency domain expressions. That way, an efficient and accurate synthesis tool can be obtained.

Novel Coplanar Ultra-Wideband Antennas Designed by Global Optimization Method

The presented text deals with design of the modification of the low-profile dipole planar inverted cone antenna (LPdiPICA), which is originally modified. The motive of the antenna was designed in CST Microwave Studio and optimized in the MATLAB by the particle swarm optimization method (PSO) and originally modified genetic algorithms (GA). The parameters s11 was wideband optimized in frequency range from 3 GHz to 7 GHz. In the first part, the basic motive of the coplanar antenna is described. In the second part, the global optimization of the antenna by PSO and GA is proposed. In the third part, the numerical example is shown: an antenna optimized wideband frequency range from 3 to 7 GHz. The best antenna is then solved from 1 to 10 GHz.

Novel planar wideband antennas designed by multi-thread hybrid optimization method

In the proposed paper, novel types of genetic algorithms are used as the global optimization method to seek the geometry of ultra-band planar directional antenna. The global optimization method is real codes genetic algorithms SPX-PNX used for accurate results of optimization with local Quasi-Newton optimization method. For accurate and wideband computation, the method of moments is used in frequency domain and for multi-thread parallel optimization for fast computing in MATLAB environment. The antenna is optimized for two basic parameters: wideband impedance matching and directivity pattern of the antenna. A designed antenna is verified in CST Microwave Studio.

Vertically polarized antenna system for television broadcasting services

In the paper, the design and simulation of a transmit antenna system with vertical polarization is discussed. The antenna is designed for television broadcasting services. The improvement of antenna properties is achieved by using a special balun with a shunt matching and an inner compensation transmission line. The feeding network of the antenna is deeply discussed. The antenna is simulated in CST Microwave Studio. Experimental verification of antenna properties is under preparation.

Novel fractal modification of wideband cone antenna designed by global optimization method

In the proposed paper, a novel types of genetic algorithms are used as a global optimization method to seek the geometry of ultra-band discone antenna with Koch motive. The global optimization method is real codes genetic algorithms SPX-PNX used for accurate results of optimization. For accurate and wideband computation, time domain method in CST MW Studio is used. The antenna is optimized for two basic parameters: wideband impedance matching and directivity pattern of the antenna.

Novel ultra-wideband slot-line antenna designed by adaptive real coded genetic algorithm

In the proposed paper, a novel types of genetic algorithms are used as a global optimization method to seek the geometry of ultra-band slot-line antenna (UWB SLA). The global optimization method is combined with local optimization method for accurate results of optimization. For accurate and wideband computation, time domain method in CST MW Studio is used. The antenna is optimized for two basic parameters: wideband impedance matching and directivity pattern of the antenna.

Modeling of a Rotational Spectrometer by Ray Tracing Methods

In this paper the ray tracing method is developed and used for the modeling of a rotational spectrometer. Since the electrical size of the spectrometer is several thousands times longer compared to the wavelength, the presented approach is much suitable for the analysis of such huge devices than the classical numerical exact methods such as the fast integral methods.