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A dielectric rod antenna designed for maximal gain at the frequency band of 5-6 GHz is presented in this paper. A simulation using CST Microwave Studio results in gains of 12 to 15 dBi with beamwidths of 30° in both E and H planes making the dielectric rod antenna a sensible alternative to Yagi-Uda antennas as it performs in a similar fashion and is less sensitive to manufacturing tolerances. Multiple...
The Characterlstic Mode Analysis (CMA) provides a set of eigenvalues and eigenvectors that are determined entirely by the antenna array structure at a particular frequency. The presented method solely relies on the mutual impedance matri:s: of elements of the array. In turn, the proposed approach is yery fast. Various modal decompositions are performed on an array of parallel dipoles placed horizontally...
Various modal decompositions are performed on an array of dipoles backed by electric ground plane. The theory is based on analytically prescribed current on dipoles so the decomposition returns directly excitation coefficients of an array with respect to given quantity.
Two different array of dipoles above infinite electric ground plane are optimized for bandwidth using particle swarm optimizer, concept of self and mutual impedances and impedance quality factor. It is found that it is the interaction of mutual radiated power that limits the bandwidth, rather than stored energies.
Characteristic mode decomposition represents popular and powerful numerical method which offers deep physical insight into radiation mechanisms and an effective framework for small antenna design. The quality of resultant characteristic basis is strongly dependent on the properties of the impedance matrix but also on utilized factorization technique, or the exact shape of the radiator. In this contribution,...
This contribution presents a recent development of the Antenna Toolbox for Matlab (AToM). The toolbox utilize novel theoretical findings related to characteristic mode decomposition and the so-called source concept, by which all antenna characteristics are represented solely by means of currents.
A novel method for evaluation of the stored energy contained in a non-stationary electromagnetic field is presented in this paper. The method utilizes the classical definition of the radiated energy, which subtraction from the total electromagnetic energy is carried out in time domain during a transient state of the system under study.
This paper presents the development of simulation models for proton and carbon irradiated 4H-SiC junction barrier Schottky (JBS) diodes. Compared to protons, heavier carbon ions introduce more defects with deeper levels in the SiC bandgap and more stable damage. For the first time, the free carrier concentration profile extracted from CV simulations for irradiated JBS diode has been compared with...
New expressions for calculating of the quality factor QZ are presented. The resulting relations link QZ, based on the frequency change of the input impedance at the input port, with expressions based solely on the current distribution on a radiator. The derivation is based on electromagnetic potentials, automatically eliminating all divergent integrals associated with electromagnetic energies in infinite...
This paper describes an analytical evaluation of the measurable quality factor QZ of a system in which the vector potential is known. The method is presented on a canonical example of the currents flowing on a spherical shell, which leads to the analytical prescription for the lower bound of QZ.
Radiation efficiency is an important parameter, especially for electrically small antennas. It can be computed directly from the method-of-moments impedance matrix, and also more generally by employing modal decomposition through characteristic modes. This advantageously enables us to study separately the effect of the radiating shape and the feeding. The proposed method does not require any modification...
Complex in-house tool for calculation of characteristic modes has been shortly introduced. Then some bottlenecks were identified and modified into parallel and distributive computing mode. One example has been completely adapted to GPU device. Preliminary tests show that practical parallel programing in Matlab is easy and very effective. Further development will be aimed to utilization more than one...
Two approaches, Virtual Reality Modeling Language (VRML) and graphic library OpenGL, are used for active stereoscopic vision of electromagnetic fields surrounding selected antenna or microwave elements. Input data are generated by analytical relations or acquired by electromagnetic field simulators and visualized in the form of vector fields and field lines by active stereoscopy. In case of VRML freeware...
Paper describes usage of the IFS (Iterated Function System) fractals employed as a planar microstrip patch antennas. To generate the IFS fractals, versatile tool named IFSMaker has been evolved. Efficient design of patches will be shown. After fractal pre-design, one can start to optimize the IFS collage by using the PSO algorithm. This procedure is managed by the PSOptimizer tool. Optimalization...
In this contribution a novel configuration of high-directivity broadband antenna is presented. Its main operational principle is based on the so-called “short backfire” (SBF) concept, however, instead of conventional dipole, rectangular microstrip patch is used as feeder.
A multibandband patch antenna design based on the Genetic Algorithm (GA) control of the pseudorandom generation of the patch topology in a grid of conductive cells is presented. GA operates on subdomains of the basic grid forming an original rectangular patch and creates meander edge notches to modify the radiator for excitation of higher order modes with the required radiation properties. Matlab/IE3D...
The article presents results of systematic investigation on annealing of radiation defects introduced into n-type oxygen-rich float-zone silicon by single (7 MeV) and double energy (7 and 7.6 MeV) alpha-particle irradiation with fluences form 8.5 times 108 to 1 times 1012 cm-2. Effect of isochronal anneal in the temperature range from 100 to 500degC on introduced defects and their interaction was...
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