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In recent years, the number of publications dealing with the use of electromagnetic band gap (EBG) structures in antenna engineering has been increased rapidly. However, there is only a few papers describing the pros and cons of different EBG structures. In this contribution, a comparative study of planar versus volumetric EBG structure is presented. The emphasis is placed on the ability of the EBG's...
A proper construction of Green's functions for planar electromagnetic structures is the foremost task in the numerical analysis of microstrip antennas using integral equation techniques. In the paper, Green's functions for a planar structure are formulated in the frequency domain and in the time domain. In the frequency domain, Sommerfeld type integrals are involved, and in the time domain, the Cagniard-de...
The paper deals with the multi-physical analysis of the Gunn diode. The electrostatic, drift-diffusion and thermal phenomena are considered in the physical model of the component. The basic equations are summarized, and modeling issues are discussed. The analysis was performed in COMSOL Multiphysics using finite element method.
A method of modeling a small aircraft with composite parts is described. The model is tailored to simulate the influence of a HIRF environment. In order to simplify the analysis, the dielectric material with suitable parameters is used instead of a complicated composite structure. The influence of composite parts on electromagnetic properties of the model is illustrated by electric field distributions...
This paper focuses on the applicability of electromagnetic band gap structures in the domain of antennas to suppress surface waves if used as a substrate. For the simplicity monopole antenna together with grounding plane was studied and results of far field is simulated and compared. Far field pattern and the influence of gap selection is further studied. Convenience of both guiding and radiating...
A comparative study of two approaches to the design of planar antennas on EBG substrates is presented in the paper. Attention is focused to the match between the required parameters of the designed antennas and obtained ones. The final discussion results in methodological recommendations, which can ensure a proper functionality of the designed structure.
The paper present original results of the numerical study of the multiple crossover and mutation to the convergence of the genetic optimization. The numerical study includes the minimization of special one- and two-dimensional functions, and also real functions from the area of computational electromagnetics.
In the paper, the dispersion analysis of planar metallo-dielectric electromagnetic band gap (MD-EBG) structures in Ansoft HFSS is discussed. The attention is turned to critical settings of unit cell modeling for the correct computation of the dispersion diagram. First, a dispersion analysis of the original uniplanar compact photonic band gap (UC-PBG) structure was done, and the results were compared...
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...
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...
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.
The presented text deals with design of the modification of the low-profile dipole planar inverted cone antenna (LPdiPICA) which is in the text originally modified. In the literature, the original antenna is fed symmetrically. In our case, the symmetrical feeding to coplanar feeding is changed. The motive of the antenna was designed and optimized in Zeland IE3D full-wave EM solver. The parameters...
This paper deals with modeling of the ultra-wideband planar antennas with coplanar feeding in the commercial available programs. After a brief summary of the basic principles of high-frequency structures modeling, a specific design of wideband antennas on two different substrates is shown. The antennas are modeled in CST Microwave Studio and Zeland IE3D. Simulation results are compared to measured...
This paper deals with the original synthesis of the frequency selective surfaces (FSS) with using global optimization methods. For the optimization, the genetic algorithm method (GA) and particle swarm optimization method (PSO) are used. The optimization methods are implemented in MATLAB and combined with CST Microwave Studio which is used as the computational kernel. This combination of the modification...
The paper deals with an enhanced neural modeling algorithm based on incorporation of both, global optimization method and local one. Proposed algorithm depresses disadvantages of classical neural modeling. A neural model of the low-pass filter is trained to behave as a numerical one, which is analyzed in Zeland IE3D. Both, the neural model and the numerical one are optimized using particle swarm optimization...
The paper is focused on the time domain modeling of antennas by the method of moments. For this modeling, a scheme with weighted Laguerre polynomials is used. For efficient using of this scheme, the scaling factor of the time axis and the number of temporal basis functions has to be determined properly. Otherwise, the scheme is inaccurate and time-consuming. In this paper, several clues how those...
The paper presents dual band (2.4 GHz and 5.3 GHz) antenna design. Printed dipole with modified structure is used as an active element, frequency selective surfaces on dual parallel plates are used as reflectors and feeding and impedance matching is outlined. The design is made in IE3D (method of moments).
A method of enforcing a patch antenna to operate in multiple frequency bands is described in the paper. The original approach consists in etching multiple U-shaped notches to the patch, which divide the rectangular antenna element to sub-radiators. Changing dimensions of sub-radiators, the antenna can be tuned to resonate on required frequencies.
A rapid development of communication technologies requires electrical engineers to be continuously educated. Due to the high time demands of their jobs, employers ask technical universities to prepare e-learning courses accessible via Internet. The paper presents two Internet textbooks covering the area of analysis and optimization of microwave structures. Discussion is turned to structuring textbooks,...
Due to the global status of today's electronics industry, prospective employees educated by technical universities are expected to be able working in multi-national teams, attending international courses of highly specialized education, effectively sharing their knowledge and abilities. In order to prepare students to the described situation, approximately 20 European universities have organized the...
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