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In this paper, the effects of geometrical perturbations on the geometry of a reference fractal antenna have been carefully analyzed to provide a set of analytic rules for describing the resonant behavior of the antenna. As regards to the antenna synthesis, the obtained results can be profitably used to initialize an optimization process for identifying an optimal solution thus allowing non-negligible...
In this work, the sequential code developed is effectively parallelized using the MPI. All objects are 2D perfect electric conductors (PEC) immersed in air. The illuminating waves are transverse magnetic (TM) plane waves where the electric field is parallel to the axes of the cylinders. The objective is to retrieve the number of scattering objects, their shapes and locations in few minutes versus...
Recently, automated identification techniques that utilize radio frequency (RF) systems have experienced growth both in the industry and in research worldwide. The current state-of-art of this identification realm is the radio frequency identification (RFID) system, which utilizes a transponder with a unique identifier. RFID systems can be classified into active systems (with built-in power supply),...
In this paper, for hyperthermia treatment at head and neck region, the optimized patient positions were proposed for different target regions with the proposed applicator. The simulation results showed that the optimization of the patient positions makes more elements have significant contribution. More important, the applicator with the optimized patient positions provides sufficient exposure to...
Recently, a novel global optimization technique, Taguchi's method was introduced to electromagnetic (EM) community and successfully has applied to optimize some EM applications such as linear array synthesis, ultra-wideband (UWB) antenna, planar filter designs, which demonstrated its great potential on optimization and its advantages of solving complex problem ability, good convergence, and easy coding...
Vias can introduce impedance discontinuity, slow down signal edge rate, add jitter and reduce eye openings, and cause data misinterpretation by the receiver in high-speed channel. This paper presents the design and optimization of differential vias for high-speed serial ATA connection at the data rate of 6 Gb/s. First, differential vias on a specific stackup were modeled in the 3D full-wave solver...
The batwing antenna is widely used at UHF frequencies, and typically has a 1.1:1 VSWR bandwidth of 30% or more. Particle swarm optimization was used to design HF versions of the antennas, which demonstrate a similarly wide VSWR bandwidth.
The applicability and efficiency of the invasive weed optimization, invented optimizer, for linear antenna array synthesis were investigated. It was shown that this new optimization method outperforms the PSO in the convergence speed and final error level.
The application of all sort of optimization techniques to different array pattern synthesis problems has been widely studied since the early days of antenna array design. Most of these works (generally having constraints on the array configuration) take for granted several assumptions, among which one can highlight considering isotropic sources and not taking into account coupling between array elements...
This paper presents a systematic methodology to design a tunable inductor for potential applications of contactless couplers. The design applies the Ansoft software tool HFSS (High Frequency Structure Simulator) in conjunction with Microsoft Visual C++ programming to optimize an inductor's dimensions, e.g., number of trace turns, diameter of the wire, and diameter of the ferrite core. The proposed...
A rigorous three-dimensional (3D) inversion algorithm is presented. A Gauss-Newton minimization approach is employed using a multiplicative cost function. In order to enhance the robustness of the algorithm, a non-linear transformation is incorporated for constraining the minimum and maximum values of the conductivity distribution. A line-search procedure for enforcing the error reduction in the cost...
In this work, a specific type of UWB monopole antenna is presented. This type of antenna makes use of a dielectric coating for the monopole which is used both as a radome and to configure the radiation characteristics of the antenna itself. Making use of a dielectric material with a relatively high dielectric constant but easy to work with (for manufacturing purposes), fields radiated from the monopole...
This article introduces a new design technique for producing matched magneto-dielectric metamaterial slabs. The technique is based on a genetic algorithm for the optimization of thin metallo-dielectric metasurfaces. These metasurfaces comprise of a periodic array of electrically small unit cells and backed by a perfectly conducting ground plane. Examples are also presented to show the effectiveness...
The tool has been tested on several scenes with increasing complexity and the corresponding computational cost has been evaluated, confirming the expected speed and accuracy. The extensive testing has also shown that a deeper optimization of the code can further increase its performances. Improvements are expected by compressing the Beam Output File. While changes to the geometry data structure and...
In this paper, we present an analytical view of the maximum far-field tag gain of a typical commercially available passive UHF RFID tag design operating at 915 MHz, which is the center frequency of the Industrial, Science, and Medical (ISM) band. The far field gain is calculated using FEKO 5.3 designed by EMSS, which is a computational electromagnetic (CEM) tool, and the method used here includes...
This paper investigates the performance improvement in computational time achieved by the use of field programmable gate arrays (FPGAs) in electromagnetic simulations. The amplitudes of a linear phased array antenna are optimized to reduce the interference in multi-beam satellite communication systems by implementing the optimization algorithm and the antenna pattern calculations on a single FPGA...
A shape-gradient optimization based on contour deformations by means of Level Set method is used for reconstructing 2-D and 3-D perfectly conducting objects electromagnetic imaging. A frequency hopping technique is applied during the inverse scattering procedure for first locating the objects and reconstruct them roughly, then with higher frequencies to allow finer details to be retrieved. The numerical...
Modern evolutionary optimization techniques have aroused great interest among the scientific and technical community in a wide variety of fields for the last years, because of their ability to solve problems with a non-linear and non-convex dependence of design parameters.In this paper a comparison of GA, PSO and DE for the design of scannable circular antenna arrays is presented. The purpose and...
In this paper, the versatility and usefulness of convex optimization is illustrated. A sidelobe-minimizing weighting method will be presented that returns optimal weights given a set of specifications, including: scan direction, beamwidth, array geometry, set of null constraints and smoothness criteria. The method also takes into account the radiation patterns of the elements, which do not have to...
A Yagi-type antenna is presented for the shaped radiation pattern synthesis, which will become very useful in the applications of wireless communications. The shaped pattern is formed by properly allocating the directors to weight the directivities in a various directions since the uses of directors have been shown to increase the directivity of a Yagi antenna radiation. Both numerical and experimental...
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