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A multi-frequency printed microwave absorber with very close absorption peaks is designed using a dual-layer technique. The absorption ranges are applicable in the lower WiMAX bands with the adjacent bands (i.e. 2.3/2.7GHz), and also covering almost all U-NII-1/2/3 bands. The absorber consists of two layers with simple rectangular copper patterns, which can improve the modeling and manufacturing accuracy...
Unlike most researches focus on computation reduction, the fast algorithm proposed in this paper aims at maintaining the coding efficiency as high as possible. In the proposed algorithm we employ support vector machine (SVM) that uses three parameters as features: variances, low-frequency AC components of DCT and spatially neighboring CU levels for fast CU size decision. In addition, based upon RMD...
An equivalent circuit model for a multiple resonance reflectarray element is presents in this study. It allows predicting the broadband characteristics of the element from only a few full wave simulations. The equivalent circuit approach can provide good insight into the physical and design properties of periodic structure.
This paper proposes and demonstrates 4×1 multi-input single-output magnetic resonance wireless power transfer system with beamforming control. The beamforming control drastically improves the transmission efficiency. The phase and amplitude of the input voltage at each TX coil are optimized to maximize the efficiency. The efficiency of the proposed system is more than 60% improvement compared with...
The current investigation utilises cold spray technology to coat specimens which are experimentally tested to analyse pool boiling enhancement. The coatings are generated from a 50/50 volume aluminium/copper feedstock powder mixture that is cold sprayed onto a copper substrate. After spraying, the aluminium content is etched, using NaOH, resulting in a surface with increased surface porosity, area...
In pursuing higher power density power electronic equipment, the copper clip bonding concept is one of the double-sided cooling approaches under investigation for power semiconductors. This paper presents a comprehensive thermal assessment of the copper clip concept by undertaking comparative studies on one bespoke copper-clip-bonded IGBT power module and a conventional wire-bonded counterpart. A...
The use of linear alternators are increasing daily with the usage in hybrid vehicles, Stirling power engines, free piston engines and other renewable energy technologies. Detailed study on the usage of radial or axial magnets in the linear alternator has not been performed so far. This paper attempts to study the effects of the radial magnets and axial magnets under the same conditions using ANSYS...
Packages of commercial Gallium-Nitride power semiconductors present increasingly small dimensions to enable low parasitic inductance, increasing the heat flux density of the package and the challenges associated with their thermal management. This paper compares between Printed Circuit Boards and Direct Copper Bonded as substrates for a Gallium Nitride based half-bridge from a thermal and reliability...
Electrically Excited Synchronous Motor (EESM) serves as an option on hybrid vehicle applications. An EESM for mild hybrid application is designed in this study. Copper loss minimization and field current minimization are analyzed for current control strategies of EESM. Both of the current control strategies are applied and comparisons between the two are made thereafter. In both of the strategies,...
Geological repositories are planned to be used for the long-term storage of Swedish nuclear spent fuel. Copper canisters will preserve the fuel underground for thousands of years. The IAEA (International Atomic Energy Agency) and EURATOM safeguards approaches propose to use canisters identification to support the Continuity of Knowledge (CoK) from the encapsulation plant to the final repository [1]...
A segment type linear switched reluctance motor is proposed for a linear actuator or a liner generator. A flat gap motor and a cylindrical gap motor are designed and their characteristics are compared. The movers have concentrated armature windings. The stators consist of segment cores and aluminum block bodies. The characteristics are calculated using a finite element method analysis. The efficiency...
The paper describes a 3D semi-analytical harmonic modeling technique, which is capable to model eddy current distributions in conducting structures and the associated fields. The induced current density and magnetic fields in the spectral domain are described, where a spatially varying conductivity of a conducting region is incorporated in the solutions of magnetic-field quantities. An experimental...
A tunable aperture using a metal expansion by Joule's heating which operates when the voltage is applied to two copper metal structures having high thermal resistance is proposed. This aperture has four thermal actuators that can obtain 3D image and distance information in a single camera. The proposed thermal actuator is based on two slightly bent beams that can actuated in directed direction and...
In the existing electronic devises, chip-to-chip and on-chip interconnects are based on copper wires. However, copper interconnects have created problems on the performance and functionality of conventional electronics devices by imposing parasitic load that leads to limit in speed, lower bandwidth, increased power consumption(high heating on the devices) and electromagnetic interferences. On the...
In this paper, a lamination of a magnetic sheet and a copper sheet is proposed to obtain wideband shielding effect from kHz to MHz bands. The requirement of the laminated magnetic sheet was discussed. A cap type shield case applying the laminated sheet 53 μm thick was fabricated and its shielding effect was measured. The higher shielding effect was obtained using the proposed sheet in the frequency...
This paper presents an efficient method to measure physical parameters of thin elastic layers by using an air-coupled ultrasound technique. In the method, surface densities of elastic thin layers are approximated through solely non-contact measurement of through-transmission of ultrasonic signals. A copper foil and a copper foil coated with carbon composite on both sides are used to experimentally...
In order to calculate the copper loss calculation with coil end effect in a practical computation time, the zooming method, which is one of the model reduction methods, is applied to the analysis of an three-phase synchronous motor. Moreover, the faster calculation technique is proposed for the analysis of three-phase synchronous motor. The copper loss of litz wire with a coil end can be calculated...
The use of electromagnetic shielding materials continues to grow in terms of research and application at various areas. In this paper, shielding effectiveness measurements are conducted to investigate the behavior of three different materials against electromagnetic fields. These materials are copper wire mesh, galvanized wire mesh, and aluminum plate. The purpose of using wire mesh structures is...
Failure of tap changer is a significant issue in reliability of a distribution transformer. For this reason, the tap changer faults requires detail investigation in order to understand the main causes. This paper presents an investigation to determine the applicability of using frequency response analysis measurement for diagnosing faults on tap changer. Two faults have been investigated were coking...
Adaptive control of an interior permanent magnet synchronous motor (IPMSM) has been proposed for compensation of parameter uncertainties. However, the control Lyapunov function (CLF) utilized in the method has a problem that the function is not a global one. In this research, we devise a global control law by using a global CLF designed with the multilayer minimum projection method. Moreover, we show...
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