Publisher: Advanced Electromagnetics   (Total: 1 journals)   [Sort by number of followers]

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Advanced Electromagnetics     Open Access   (Followers: 19, SJR: 0.154, CiteScore: 1)
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Advanced Electromagnetics
Journal Prestige (SJR): 0.154
Citation Impact (citeScore): 1
Number of Followers: 19  

  This is an Open Access Journal Open Access journal
ISSN (Online) 2119-0275
Published by Advanced Electromagnetics Homepage  [1 journal]
  • A Methodology for Optimal Design of Transmission Lines to Protection
           against Lightning Surges in Presence of Arresters

    • Authors: R. Shariatinasab; R. Azimi
      Abstract: In this paper, a methodology for determination of the optimal value of protection design parameters, i.e. tower footing resistance, insulation strength, and surge arresters’ rating in the planning stage of transmission lines (TLs) is presented. This method calculates the shielding failure flashover rate (SFFOR) of TLs, based on Electro-geometric model (EGM) of TLs, and the back flashover rate (BFR) of TLs, based on the Monte Carlo method, in which the accuracy of the proposed methodology has been verified by comparing the resultant results with those obtained with the use of the IEEE FLASH program. The proposed method can be directly used to achieve the minimum lightning flashover rate (LFOR) of TLs by the minimum investment cost. Also, it can be used, indirectly, for determination of the appropriate value of the footing resistance, insulation strength and arresters’ rating to satisfy any target number of LFOR that might be specified by the utilities or standards.
      PubDate: Sun, 05 Jul 2020 07:20:13 -040
       
  • Size Miniaturized Coaxial Probe Fed Antenna for Multiband Applications

    • Authors: B. Heydarpanah; C. Ghobadi, J. Nourinia, P. Beigi, M. Majidzadeh
      Abstract: A novel coaxial cable-fed antenna with a combination of L-shaped elements is proposed for multiband applications. The obtained resonances at different frequency bands are realized by adding L-shaped strips with different lengths to the antenna geometry. The antenna is printed on a low-priced FR-4 substrate with overall size of 14×14×1.6 mm3. Experimental results indicate the coverage of 1.32, 1.80, 2.34, 3.30, 3.66, 4.26, 5.28, 7.68, 8.1, 9.72 and 10.38 GHz, compatible with L-band, WLAN, WiMAX, C-band, ITU 8 GHz, and X-band. Suitable radiation properties, multiband functionality, desirable gain values and agreement of simulated and measured results confirm the suitability of the proposed structure for multiband communication applications.
      PubDate: Sat, 09 May 2020 11:46:42 -040
       
  • On the coupling of forward and backward slow waves supported by the
           waveguide configuration of a dielectric sandwiched between two plasma
           slabs

    • Authors: E. Yasin; A. AlKhateeb, F. Rawwagah, A. Abuzir
      Abstract: We derived a general equation governing the spectra of electrostatic surface plasmons supported by a waveguide structure of two identical plasma slabs separated by a dielectric medium. The plasma slabs are parallel, homogeneous, and have finite thicknesses. The geometry under consideration supports two surface plasmon modes, which we investigated numerically for Polyethylene $\varepsilon_d=2.25$ and vacuum $\varepsilon_d=1$ as central regions. With vacuum as a central region, the two surface plasmon modes become coupled and merge into the well known single mode of quasi-static frequency $\omega=0.707\omega_{\rm p}$. The surface plasmon modes in the presence of a Polyethylene are decoupled and remain nondegenerate over the whole range of $kd$. Therefore, the two plasmon modes propagate independent of each other with distinct quasi-static resonance frequencies, namely, a backward wave with $\omega=0.707\omega_{\rm p}$ corresponding to a single plasma-vacuum interface and a forward wave with $\omega=\frac{\omega_{\rm p}}{\sqrt{3.25}}=0.55\omega_{\rm p}$ corresponding to a single plasma-dielectric interface. Increasing the central region width is found to introduce a delay in reaching the quasi-static resonance frequencies. The effect of collision is to down shift the mode frequencies for long wavelengths and also to down shift the quasi-static frequencies.
      PubDate: Fri, 01 May 2020 11:21:39 -040
       
  • Design of Plasmonic NOT Logic Gate Based on Insulator – Metal –
           Insulator (IMI) waveguides

    • Authors: H. F. Fakhruldeen; T. S. Mansour
      Abstract:    In this work, all-optical plasmonic NOT logic gate was proposed using Insulator-Metal-Insulator (IMI) plasmonic waveguides Technology. The proposed all-optical NOT gate is simulated and realized using COMSOL Multiphysics 5.3a software. Recently, plasmonic technology has attracted high attention due to its wide applications in all-optical signal processing. Due to its highly localization to metallic surfaces, surface plasmon (SP) may have huge applications in sub wavelength to guide the optical signal in the waveguides which results in overcoming the diffraction limit problem in conventional optics. The proposed IMI structure is consist of a dielectric waveguides plus metallic claddings, which guide the incident light strongly in the insulator region. Our design consists of symmetric nano-rings structures with two straight waveguides which based on IMI structure. The operation of all-optical NOT gate is realized by employing the constructive and destructive interface between the straight waveguides and the nano-rings structure waveguides. There are three ports in the proposed design, input, control and output ports. The activation of control port is always ON. By changing the structure dimensions, the materials, the phase of the applied optical signal to the input and control ports, the optical transmission at the output port is changed. In our proposed structure, the insulator dielectric material is glass and the metal material is silver. The calculated contrast ratio between (ON and OFF) output states is 3.16 (dB).
      PubDate: Tue, 07 Apr 2020 06:22:26 -040
       
  • Optimization of the Method of Auxiliary Sources by the Genetic Algorithm
           for electromagnetic scattering problem

    • Authors: S. Hidouri; T. Aguili
      Abstract: In this paper, we propose to apply a technique of optimization of the convergence of the auxiliary sources method (MAS) for the problems of electromagnetic diffusion by a perfectly conducting and infinite obstacle. This technique is based on the use of the genetic algorithm (GA). Previous studies have shown that the convergence of the MAS solution depends on many parameters such as the number of auxiliary sources and the auxiliary distance between the real surface of the cylinder and the fictitious surface, and so on. The solution is obtained for a good choice of these parameters. In this article, the genetic algorithm is chosen to facilitate the choice of MAS parameters.
      PubDate: Sun, 22 Mar 2020 11:17:03 -040
       
  • A Design of MIMO Prototype in C-Band Frequency for Future Wireless
           Communications

    • Authors: N. M. K. Al-Ani; O. A. S. Al-Ani, M. F. Mosleh, R. A. Abd-Alhameed
      Abstract: The main challenges of MIMO design for future wireless communication is size reduction which leads to more mutual coupling. This paper deals with this problem in order to mitigate the impact of mutual coupling by proposing four elements MIMO prototype each one having a dual polarized patch rectangular microstrips. The idea is to insert annular rectangular opened one ribs in front of each microstrip and in corresponding to circular ring slot etched has etched in the ground. The advantage of such slot is to obtain regular radiation pattern distributed around device body. The four elements with eight ports are incorporated on 67×139 mm2 PCB with FR-4 dielectric layer. The single antenna is simulated CST.STUDIO 2019 resulting an operated frequency of 6.23 GHz with a band of 850 MHz (5.81-6.66) GHz at -10 dB. The fabrication MIMO system prototype is tested to show its measurement results which are match the simulated results. All results confirm of that proposed MIMO prototype which is operated at C-band frequency which is very important for future wireless applications.
      PubDate: Sun, 22 Mar 2020 07:09:34 -040
       
  • Validity of Improved MTL for Effective Length of Counterpoise Wires under
           Low and High-Valued Lightning Currents

    • Authors: S. R. Ostadzadeh
      Abstract: In this paper, an efficient modeling approach called improved MTL is used to predict effective length of counterpoise wires considering both ionization and dispersion of soils. This paper consists of two parts. At first part, validity of the model for computing effective length of counterpoise wires considering only soil ionization is investigated. The simulation results show that the improved MTL-based effective length of counterpoise wire are in good agreement with the existing formulae. Application of this modeling approach to include ionization and dispersion effects simultaneously (both-affected soil) is carried out in the second part. The simulation results show that in both-affected soils, the effective length with respect to only-ionized soils, is decreased especially in highly resistive soils under slow-fronted currents. This makes inclusion of both effects financially important in designing counterpoise wires.
      PubDate: Sat, 21 Mar 2020 15:49:50 -040
       
  • Dual Band Filter-Antenna with Fixed Low Band and Frequency-Agile High Band
           for Wireless Communications

    • Authors: H. A. Atallah
      Abstract: This work proposes a design of compact filter-antenna with fixed and frequency-agile bands for wireless communications and cognitive radio (CR) systems. The filter-antenna is realized by attaching a bandpass filter with an independent fixed band and a tunable band to a UWB antenna. The dual bandpass filter consists of a folded open loop resonator loaded with single varactor diode at a suitable location to achieve reconfigurability operations for the high band while the low band remains fixed at 4.5 GHz. A reconfigurable broadband frequency range of 3.2 GHz from 7.8 to 4.6 GHz is achieved for the high band by changing the capacitance of the varactor from 0.16 to 2.25 pF, respectively. A prototype of the filter-antenna is fabricated and measured at a selected capacitance of 0.6 pF to verify the simulation results. Good agreements between simulated and measured results are obtained.
      PubDate: Sat, 21 Mar 2020 12:40:43 -040
       
  • A Compact Wide Bandpass Filter for Satellite Communications with Improved
           Out-of-Band Rejection

    • Authors: B. Ait Ahmed; A. Naghar, O. Aghzout, A. Vazquez Alejos, F. Falcone
      Abstract: This paper presents a compact C-band bandpass filter with improved out-of-band rejection. It consists of a symmetric three-pole parallel coupled line microstrip loaded with complementary split ring resonators (CSRRs) and slot resonators. Enhancements regarding the filter responses are obtained by etching these two parasitic shapes successively. When, CSRRs are introduced in the ground plane, exactly in the back of the transmission line of 50 -Ohms , improvements on the filter selectivity level are achieved. Whereas, the slot resonator elements are implemented on the feed line to permit the suppression of the second harmonics. To reduce the second harmonics of 11:1-13GHz, the parasitic elements are both combined, widen the filter rejection of 5:81%. The surface current distribution together with the equivalent circuit are also studied in order to demonstrate the slots and the CSRRs effect parameters on the behavior of the proposed filter. A prototype of the optimal filter is fabricated and measured.Theory and experiment results prove the validity of the new design procedure.
      PubDate: Fri, 20 Mar 2020 14:10:12 -040
       
  • High Order Relaxation Methods for Co-simulation of Finite Element and
           Circuit Solvers

    • Authors: J. D. Nshimiyimana; F. Plumier, C. Ndagije, J. Gyselinck, C. Geuzain
      Abstract: Coupled problems result in very stiff problems whose char- acteristic parameters differ with several orders in magni- tude. For such complex problems, solving them monolithi- cally becomes prohibitive. Since nowadays there are op- timized solvers for particular problems, solving uncoupled problems becomes easy since each can be solved indepen- dently with its dedicated optimized tools. Therefore the co-simulation of the sub-problems solvers is encouraged. The design of the transmission coupling conditions between solvers plays a fundamental role. The current paper ap- plies the waveform relaxation methods for co-simulation of the finite element and circuit solvers by also investigating the contribution of higher order integration methods. The method is illustrated on a coupled finite element inductor and a boost converter and focuses on the comparison of the transmission coupling conditions based on the waveform iteration numbers between the two sub-solvers. We demon- strate that for lightly coupled systems the dynamic iterations between the sub-solvers depends much on the inter- nal integrators in individual sub-solvers whereas for tightly coupled systems it depends also to the kind of transmission coupling conditions.
      PubDate: Fri, 20 Mar 2020 09:47:39 -040
       
 
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