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International Journal of Electromagnetics and Applications
Number of Followers: 3

This is an Open Access Journal

Open Access journal
ISSN (Print) 2168-5037 - ISSN (Online) 2168-5045
Published by SAP

[105 journals]

Core Losses Analysis for Soft Magnetic Materials under SPWM Excitations
- Abstract: Publication year: 2020Source: International Journal of Electromagnetics and Applications, Volume 10, Number 1Htutzaw Hein, Yongjian Li, Shuaichao Yue, He SunThis paper illustrates the core loss analysis for non-grain-oriented silicon steel, grain-oriented silicon steel, and soft magnetic composite (SMC) materials under sinusoidal excitation and Sinusoidal Pulse Width Modulated (SPWM) excitations. The SPWM voltages with their modulation and carrier ratio have been created by MATLAB for experimental verification. The standardized measurement methods: Epstein Frame method and ring sample method, have been used to test the soft magnetic materials. The core losses from different experimental data have been analyzed. The results show that the core losses under three different SPWM excitations depending on the modulation and carrier ratios of PWM waveforms are different from the core losses supplied by sinusoidal excitations. And also, it can be found that the magnetic behavior of the material affects the core loss under non-sinusoidal excitation.
Optimization of Optical Parametric Amplification Efficiency in a
Microresonator Under Ultrashort Pump Wave Excitation
- Abstract: Publication year: 2019Source: International Journal of Electromagnetics and Applications, Volume 9, Number 1Özüm Emre Aşırım, Mustafa KuzuoğluThis paper aims to computationally show that it is possible to achieve wideband high-gain optical parametric amplification in a very small low-loss microcavity. Our model involves numerical modeling of the charge polarization density in terms of the nonlinear electron cloud motion. Through a series of finite difference time domain simulations, we have determined the pump wave frequencies that maximize the electric energy density inside the microcavity. These pump wave frequencies that maximize the energy density are then selected for stimulus (input) wave amplification via nonlinear energy coupling. The achieved amplification factors are tabulated in terms of the pump wave frequency, stored electric energy density, and the intracavity charge polarization density. It is found that unlike what the current literature on nonlinear wave mixing suggests, micrometer-scale achievement of wideband high-gain optical parametric amplification is possible by choosing the optimum pump wave frequency that maximizes the stored electric energy density.
State of the Art Techniques for Cognitive Radio Antenna Design
- Abstract: Publication year: 2019Source: International Journal of Electromagnetics and Applications, Volume 9, Number 1Oluwafemi A. Ilesanmi, Charles U. Ndujiuba, Olabode Idowu-Bismark, Oluseun Oyeleke Wikiman, Sadiq Thomas, Idris MuhammadIn this letter, a survey of different recent state of the art techniques that have been deployed in the design of antennas that can perform excellently for cognitive radio application is carried out. Cognitive radio system fundamentals and antenna requirements for its smooth operations are also discussed. The performance of the antennas designed by various techniques in terms of, the radiation pattern, VSWR/Return loss, peak gain, radiation efficiency are discussed. Issues relating to the design techniques and some factors to consider when designing a suitable antenna for cognitive radio system also highlighted.
Optimizing the Absorption Capability of a Microbolometer Pixel’s
Active Element
- Abstract: Publication year: 2019Source: International Journal of Electromagnetics and Applications, Volume 9, Number 1C. Bolakis, I. S. Karanasiou, D. Grbovic, C. Vazouras, G. Karunasiri, N. UzunogluIn this paper, we propose a new approach for effective detection of THz and IR radiation, using a configuration of a thin metal and semiconductor layers. We present the design and performance of an effective absorber of radiation that can be used as the active pixel element of a microbolometer. A double-layered absorber, comprising a thin metal layer placed onto a poly-Si substrate was designed through a fine-tuning process. The results indicate that the proposed low-cost, double-layered absorber can be tuned based on the metal layer sheet resistance and the thickness of various poly-Si media. This can be done in a way that takes advantage of the diversity of the absorption of the metal films over the THz spectrum (0.1 - 10 THz) and both the mid and long wavelength IR region (3 - 14μm). A ‘’wide-spectrum linear equation’’ has been developed, having as input any discrete wavelength with desired absorption peak in the THz or IR spectrum and as output the appropriate thickness of the poly-Si medium. It was found, using this equation, that the composite absorber retains the ability to absorb 96% and reflects less than 1% of the incident power of radiation. Moreover, based on the fact that both layers of the absorber can be used as active element of a microbolometer pixel, a ‘’hybrid’’ nature of the designed absorber emerges. To this end, we compare important metrics and design complexity between the ‘’hybrid’’ absorber and a state-of-the-art microbolometric pixel element comprised either of a thin metal layer or a material with high TCR. The analysis shows that the developed absorber can be considered a promising candidate for integration into current and sophisticated microbolometer configurations.
Design of Compact Dual-band and Tri-band Microstrip Patch Antennas
- Abstract: Publication year: 2018Source: International Journal of Electromagnetics and Applications, Volume 8, Number 1Dhirgham K. NajiThree multiband microstrip patch antennas (MPAs) to operate at (3.5/5.5 GHz) WiMAX, upper (5.2/5.8 GHz) WLAN and C frequency bands are presented in this paper. The proposed antenna structures are mainly constructed from the fork-shaped monopole antenna. These three antennas (Ant.1-3) are namely mender fork-shaped antenna (MFA), spiral fork-shaped antenna (SFA) and double SFA (DSFA). All antennas are fed by coplanar waveguide (CPW) structure and printed on the front side of FR substrate with surface area of 21×21 mm2. A new approach is presented for designing the proposed antennas to resonate at the specified operating frequency bands. Initially, a conventional MPA fed by microstrip-line is designed to operate at 5.8-GHz WLAN band. Then, intermediate antenna prototype structures are obtained during the design process until achieving the desired antennas. The Ant.1 and Ant.3 gives dual-band characteristic covering 5.2/5.8 GHz-WLAN band including 5.150–5.875 GHz and 3.5/5.5 GHz-WiMAX including 3.4–3.7 GHz and 5.25–5.85 GHz, respectively. The Ant.2 gives tri-band covering the aforementioned dual-band besides to C-band 7.25 GHz (6.84 – 7.50 GHz). An electromagnetic simulator CST MWS ver. 2018 was used to analyze the designed antennas. The simulated results demonstrate that a dual- and tri-band operation can be easily provided by these antennas as well they have good dipole-like and omnidirectional radiation characteristics, stable gain and high-radiation efficiency indicating that the proposed antennas are candidate for WLAN/WiMAX applications.
Space Mission Analysis and Design for Electromagnetic Suppression of Radar
- Abstract: Publication year: 2018Source: International Journal of Electromagnetics and Applications, Volume 8, Number 1Timothy SandsInspired by aerial combat in the Balkans (Serbia and Kosovo) in 1999 with no known support suppressing enemy air defenses (SEAD) from space, this article proposes such by first introducing the reader to basic electromagnetic principles in order to evaluate the SEAD radar jamming mission from space. Next key design parameters are iterated in physics-based simulations to drive subsequent design efforts. Electromagnetic propagation equations are simulated and iterated to reveal key threshold values of key design parameters. It is revealed that only a single satellite is required for effective jamming with transmitter power of 2-9 kilowatts, transmission gain of at least 25 decibels, while maintaining a bandwidth less than 80 megahertz and assumed losses less than 30 decibels (where 10-20 decibels is typical). Using these key thresholds, space mission analysis and design (SMAD) is articulated in detail for the first time in the literature, revealing rough-order-of-magnitude budgets for system design. The design requires elements of mechanical engineering, electrical engineering, and aerospace/astronautical engineering at least. Astrodynamics reveals that a low-earth orbiting altitudes of 100-400 kilometers produces jamming effects on the target emitter for 4.8-10.2 minutes respectively producing jammer energy received by the targeted radar of -23.9 to -102.9 decibel-watts respectively. These key design features are used to establish a link-budget that reveals mission margin. Spacecraft key design budgets are calculated next revealing the requirement for a large spacecraft (~7333kg, 7.8m X 61.1m2) and large launch vehicle (Atlas V class). Budgets are also found for key satellite subsystems: payload, structures, thermal, power, TT&C, attitude control, and propellant. Reliability calculations and cost estimated are discussed, and normalized evaluation of jamming effectiveness is recommended. Lastly, key technology challenges of target acquisition, tracking, and spacecraft fine pointing are discussed, and current research efforts are highlighted inspiring future directions for technical innovations to enhance the design.
Numerical Investigation on using an Electromagnetic Wave Sensor to Detect
Water Hardness in Water Cooling System Industry
- Abstract: Publication year: 2017Source: International Journal of Electromagnetics and Applications, Volume 7, Number 2K. H. Teng, M. Ateeq, Shaw A., Al-Shamma'a A., S. N. Kazi, B. T. Chew, Kot P.Numerical study of using novel electromagnetic wave technique to detect water hardness concentration has been presented in this paper. Simulation is powerful and efficient engineering methods which allows for a quick and accurate prediction of various engineering problems. The RF module is used in this research to predict and design electromagnetic wave propagation and resonance effects of a guided wave to detect water hardness concentration in term of frequency domain, eigenfrequency and mode analysis. A cylindrical cavity resonator is simulated and designed in the electric field of fundamental mode (TM010). With the finite volume method, the three-dimensional governing equations were discretized. Boundary conditions for the simulation were the cavity materials as aluminum, two ports which include transmitting and receiving port, and assumption of vacuum inside the cavity. The designed model was success to simulate a fundamental mode and extract S21 transmission signal within 2.1 GHz – 2.8 GHz regions. The signal spectrum under effects of port selection technique and dielectric properties of different water concentration were studied. It is observed that the linear reduction of magnitude in frequency domain when concentration increase. The numerical results were validated closely by the experimental available data. Hence, conclusion of the available COMSOL simulation package is capable of providing acceptable data for microwave research.
Wireless Mobile Phones Charging – A Comprehensive Study
- Abstract: Publication year: 2017Source: International Journal of Electromagnetics and Applications, Volume 7, Number 2Ibrahim Yehya Dallal BashiIn recent years, an increasing development has been noticed in researches of wireless power transfer techniques to eliminate the use of the cables after Wi-Fi became widely utilized. When traveling, we could simply overlook about USB cables and the traditional chargers. Normally, the users of the mobile devices have the anxiety of power lack during carrying out a critical job and have no possibility of access to a charger. The users keen to always keep their mobile devices with electric power as much as possible. Also, power sharing techniques have been modified, based on user’s nearness mobile devices, that became able to get power from them. This paper will show an overview study and basis of the wireless mobile phones charging techniques.
Array Beam Scanning and Switching by Variation of Amplitude-Only
Excitations
- Abstract: Publication year: 2017Source: International Journal of Electromagnetics and Applications, Volume 7, Number 2Khalil H. Sayidmarie, Abdul-Rahman ShakeebThe conventional beam scanning in phased arrays requires either frequency scanning or phase variation for the array elements, which raise complexity and cost. Another way is presented which is simplest and inexpensive by varying the amplitude excitation of the two tilted sides of the array. Thus there is neither a need for phase variation nor a frequency sweeping. Theoretical analysis and computer simulations are presented to investigate the performance of the proposed amplitude scanning technique. The results of using two half-wave dipole elements show that the mainbeam can be scanned across ±30° with less than 1.8dB variation in the magnitude of the mainbeam.
A Review of Magneto-Optic Effects and Its Application
- Abstract: Publication year: 2017Source: International Journal of Electromagnetics and Applications, Volume 7, Number 1Taskeya HaiderThe research activities on the phenomenon of Magneto-optic Effects has recently promulgated due to its versatile use in magneto-optic recordings for high density magnetic data storage, magnetic field sensors and its applications in magneto-electronics. The discovery of magneto-optical effects evoked a new thought that the nature of light was an electromagnetic entity, and played a central role in the contribution of the development of Maxwell's electromagnetic theory. Michael Faraday was at the forefront of discovering this phenomenon, as in 1845 he showed that light interacts with magnetic fields. This study primarily focuses on the understanding of the mechanism of magneto-optic effect by reviewing and critically discussing the rotation of plane of polarization of the light beam as it is transmitted through a magnetized sample, i.e., the Faraday Effect and the rotation of the plane of polarization of a light beam during reflection from a magnetized sample, namely, the Kerr Effect. Relevant theoretical characteristics of these effects and its application in modern technology are also discussed.