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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of electromagnetic engineering and science
Journal Basic Information
Journal DOI :
The Korean Institute of Electromagnetic Engineering and Science
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Volume & Issues
Volume 11, Issue 4 - Dec 2011
Volume 11, Issue 3 - Sep 2011
Volume 11, Issue 2 - Jun 2011
Volume 11, Issue 1 - Mar 2011
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Wireless Power Transfer System
Arai, Hiroyuki ;
Journal of electromagnetic engineering and science, volume 11, issue 3, 2011, Pages 143~151
DOI : 10.5515/JKIEES.2011.11.3.143
This paper presents a survey of recent wireless power transfer systems. The issue of wireless power transfer is to achieve a highly efficient system with small positioning errors of the facilities setting. Several theories have been presented to obtain precise system design. This paper presents a summary of design theory for short range power transfer systems and detailed formulations based on a circuit model and an array of infinitesimal dipoles. In addition to these theories, this paper introduces a coil array scheme for improving the efficiency for off axis coils. In the microwave range, tightly coupled resonators provide a highly efficient power transfer system. This paper present san-overlay resonator array consisting of half wavelength microstrip line resonators on the substrate with electromagnetically coupled parasitic elements placed above the bottom resonators. The tight couplings between the waveguide and the load resonator give strong power transmission and achieve a highly efficient system, and enables a contact-less power transfer railroad. Its basic theory and a demonstration of a toy vehicle operating with this system are presented. In the last topic of this paper, harmonic suppression from the rectenna is discussed with respect to acircular microstrip antenna with slits and stubs.
Power Transmission Determined by the Mutual Impedance and the Transducer Power Gain in the Near Field Region
Kim, Che-Young ;
Journal of electromagnetic engineering and science, volume 11, issue 3, 2011, Pages 152~155
DOI : 10.5515/JKIEES.2011.11.3.152
This paper describes the role of mutual impedance and the transducer power gain which comes from key parameters to determine the amount of wireless power especially in a near-field environment. These two key parameters are applied to the two configurations; one is a dipole-dipole, and the other is a dipole-metal plate-loop configuration. Discussions are given on the achievable maximum power transfer between the sender and the receiver affected by the matching and the pass blockage.
Analysis of Magnetically Coupled Wireless Power Transmission for Maximum Efficiency
Kim, Chung-Ju ; Lee, Bom-Son ;
Journal of electromagnetic engineering and science, volume 11, issue 3, 2011, Pages 156~160
DOI : 10.5515/JKIEES.2011.11.3.156
We have proposed and analyzed an equivalent circuit for a magnetically coupled wireless power transmission (WPT) system between two loop resonators by considering its coupling coefficient and radiation-related parameters. A complete formulation is provided for all the necessary circuit parameters. The mechanism of radiation loss is sufficiently explained. The circuit and electromagnetic (EM) simulation results have been shown to be in good agreement. Based on the proposed circuit formulation, a specific load impedance for maximum WPT efficiency was found to exist. The proposed modeling of the WPT in terms of circuit characterizations provides sufficient insight into the problems associated with WPT.
Wireless Energy Transmission High-Efficiency DC-AC Converter Using High-Gain High-Efficiency Two-Stage Class-E Power Amplifier
Choi, Jae-Won ; Seo, Chul-Hun ;
Journal of electromagnetic engineering and science, volume 11, issue 3, 2011, Pages 161~165
DOI : 10.5515/JKIEES.2011.11.3.161
In this paper, a high-efficiency DC-AC converter is used for wireless energy transmission. The DC-AC convertter is implemented by combining the oscillator and power amplifier. Given that the conversion efficiency of a DC-AC converter is strongly affected by the efficiency of the power amplifier, a high-efficiency power amplifier is implemented using a class-E amplifier structure. Also, because of the low output power of the oscillator connected to the input stage of the power amplifier, a high-gain two-stage power amplifier using a drive amplifier is used to realize a high-output power DC-AC converter. The high-efficiency DC-AC converter is realized by connecting the oscillator to the input stage of the high-gain high-efficiency two-stage class-E power amplifier. The output power and the conversion efficiency of the DC-AC converter are 40.83 dBm and 87.32 %, respectively, at an operation frequency of 13.56 MHz.
Reduction of Electromagnetic Field from Wireless Power Transfer Using a Series-Parallel Resonance Circuit Topology
Kim, Jong-Hoon ; Kim, Hong-Seok ; Kim, In-Myoung ; Kim, Young-Il ; Ahn, Seung-Young ; Kim, Ji-Seong ; Kim, Joung-Ho ;
Journal of electromagnetic engineering and science, volume 11, issue 3, 2011, Pages 166~173
DOI : 10.5515/JKIEES.2011.11.3.166
In this paper, we implemented and analyzed a wireless power transfer (WPT) system with a CSPR topology. CSPR refers to constant current source, series resonance circuit topology of a transmitting coil, parallel resonance circuit topology of a receiving coil, and pure resistive loading. The transmitting coil is coupled by a magnetic field to the receiving coil without wire. Although the electromotive force (emf) is small (about 4.5V), the voltage on load resistor is 148V, because a parallel resonance scheme was adopted for the receiving coil. The implemented WPT system is designed to be able to transfer up to 1 kW power and can operate a LED TV. Before the implementation, the EMF reduction mechanism based on the use of ferrite and a metal shield box was confirmed by an EM simulation and we found that the EMF can be suppressed dramatically by using this shield. The operating frequency of the implemented WPT system is 30.7kHz and the air gap between two coils is 150mm. The power transferred to the load resistor is 147W and the real power transfer efficiency is 66.4 %.
Wireless Power Transfer Technology in On-Line Electric Vehicle
Ahn, Seung-Young ; Chun, Yang-Bae ; Cho, Dong-Ho ; Kim, Joung-Ho ;
Journal of electromagnetic engineering and science, volume 11, issue 3, 2011, Pages 174~182
DOI : 10.5515/JKIEES.2011.11.3.174
The On-line Electric Vehicle (OLEV) is an electric transport system in which the vehicle's power is transferred wirelessly from power lines underneath the surface of the road. Advantages of the OLEV include reducing battery size and cost to about 20 percent of that of conventional battery-powered electric vehicles, thereby minimizing the vehicle's weight and price, as well as the cost of charging the system. In this paper, we introduce a wireless power transfer mechanism to maximize the electrical performance of the power transfer system. Power transfer capacity, power transfer efficiency, and magnitude of leakage in the electromagnetic field (EMF) are analyzed, and the optimization methodology of the design parameters is discussed.
Analysis of Wireless Power Transfer Characteristics for Multiple Receivers by Time Sharing Technique
Park, Jong-Min ; Nam, Sang-Wook ;
Journal of electromagnetic engineering and science, volume 11, issue 3, 2011, Pages 183~185
DOI : 10.5515/JKIEES.2011.11.3.183
A multiple charging method for a wireless power transfer system (WPTS) in the near-field region is proposed. We analyzed the frequency characteristics of multiple receivers in the near-field region. The results suggested that the time division WPTS can achieve efficient and equal power transmission at multiple receivers. We conclude that this system has an advantage for charging multiple receivers.
A Method for Improving Stopband Characteristics of a Dual-Band Filter
Lee, Ja-Hyeon ; Lim, Yeong-Seog ;
Journal of electromagnetic engineering and science, volume 11, issue 3, 2011, Pages 186~191
DOI : 10.5515/JKIEES.2011.11.3.186
This paper presents a simple and effective method for improving stopband rejection characteristics of previously studied dual-band filters. Small electric couplings were applied to the symmetrically positioned shunt resonators, which divided each transmission zero into two transmission zeros without any effect on passbands. We were able to achieve improved stopband rejection characteristics by these additional transmission zeros. For the filter application, we designed a dual-band filter with improved stopband characteristics using microstrip quasi-lumped elements. The electric couplings that control the location of transmission zeros are controlled by the distance between symmetric open stubs of the filter. The filter was fabricated with a relative dielectric constant of 3.5 and a thickness of 0.76 mm. The fabricated filter has a small size (
mm) and a low insertion loss when compared with conventional filters.
Modeling of an On-Chip Power/Ground Meshed Plane Using Frequency Dependent Parameters
Hwang, Chul-Soon ; Kim, Ki-Yeong ; Pak, Jun-So ; Kim, Joung-Ho ;
Journal of electromagnetic engineering and science, volume 11, issue 3, 2011, Pages 192~200
DOI : 10.5515/JKIEES.2011.11.3.192
This paper proposes a new modeling method for estimating the impedance of an on-chip power/ground meshed plane. Frequency dependent R, L, and C parameters are extracted based on the proposed method so that the model can be applied from DC to high frequencies. The meshed plane model is composed of two parts: coplanar multi strip (CMS) and conductor-backed CMS. The conformal mapping technique and the scaled conductivity concept are used for accurate modeling of the CMS. The developed microstrip approach is applied to model the conductor-backed CMS. The proposed modeling method has been successfully verified by comparing the impedance of RLC circuit based on extracted parameters and the simulated impedance using a 3D-field solver.
Miniaturized Broadband ENG ZOR Antenna Using a High Permeability Substrate
Ko, Seung-Tae ; Lee, Jeong-Hae ;
Journal of electromagnetic engineering and science, volume 11, issue 3, 2011, Pages 201~206
DOI : 10.5515/JKIEES.2011.11.3.201
This paper presents a miniaturized epsilon negative (ENG) zeroth-order resonance (ZOR) patch antenna with an improved bandwidth. The miniaturization and the broad bandwidth of the ENG ZOR patch antenna are achieved by using a meandered via and a high permeability substrate instead of a straight via and a dielectric substrate. The use of a meandered via allows miniaturization of the ENG ZOR patch antenna without narrowing the bandwidth. The use of a high permeability substrate allows further miniaturization of the ENG ZOR patch antenna and improvement of the bandwidth. A high permeability substrate consisting of a multi-layered substrate is designed to have a small material loss. The antenna (kr=0.32) has a 10 dB fractional bandwidth of ~1 %, which is 1.74 times as broad as that of an antenna with a dielectric substrate.
Design of CPW-Fed Small Multi-Band Antenna by Using Band Rejection Semicircle Slot
Li, Xiao ; Lee, Seung-Woo ; Kim, Nam ; Kim, Chul-Ho ;
Journal of electromagnetic engineering and science, volume 11, issue 3, 2011, Pages 207~212
DOI : 10.5515/JKIEES.2011.11.3.207
This paper presents a CPW-fed antenna with three slots. The proposed antenna can operate at 1.9~2.1 GHz and 2.9~3.3 GHz which are generated by the two rectangular slots, and 4.5~11.6 GHz which is generated by the main patch. The semicircle-slot is used as a band-notched filter to stop at a desired band (5.150~5.825 GHz) limited by IEEE 802.11a or HIPERLAN/2 applications. The currents concentrate around corresponding slots at the desired band. The proposed antenna is very small in size, with overall dimensions of
etched onto an FR4-printed circuit board (PCB).
Development of Frequency Discriminated Simulative Target Generator Based on DRFM for Radar System Performance Evaluation
Chung, Myung-Soo ; Kim, Woo-Sung ; Bae, Chang-Ok ; Kang, Seung-Min ; Park, Dong-Chul ;
Journal of electromagnetic engineering and science, volume 11, issue 3, 2011, Pages 213~219
DOI : 10.5515/JKIEES.2011.11.3.213
Simulative target generators are needed for testing and calibrating various radar systems. The generator in this study discriminates the transmitting frequency from a radar and simulates parameters like target range, range rate, and atmospheric attenuation using the digital RF memory technique. The simulative target echo is then sent to the radar for testing and evaluation. This paper proposes a novel architecture for controlling the digital RF memory so it continually writes ADC data to the memory and reads it for the DAC with increasing one step address in order to control the delay of target range in a simple way. The target echo is programmed according to various preprogrammed scenarios and is generated in real time using a wireless local area network (LAN). To analyze the detected and generated target information easily, the system times for the radar and simulative target generator are synchronized using a global positioning system (GPS).
A New Resonance Prediction Method of Fabry-Perot Cavity (FPC) Antennas Enclosed with Metallic Side Walls
Kim, Dong-Ho ; Yeo, Jun-Ho ;
Journal of electromagnetic engineering and science, volume 11, issue 3, 2011, Pages 220~226
DOI : 10.5515/JKIEES.2011.11.3.220
We have proposed a new method to accurately predict the resonance of Fabry-Perot Cavity (FPC) antennas enclosed with conducting side walls. When lateral directions of an FPC antenna are not blocked with metallic walls, the conventional technique is accurate enough to predict the resonance of the FPC antenna. However, when the FPC antenna has side walls, especially for case with only a short distance between the walls, the conventional prediction method yields an inaccurate result, inevitably requiring a tedious, time-consuming tuning process to determine the correct resonant height to provide the maximum antenna gain in a target frequency band using three-dimensional full-wave computer simulations. To solve that problem, we have proposed a new resonance prediction method to provide a more accurate resonant height calculation of FPC antennas by using the well-known resonance behavior of a rectangular resonant cavity. For a more physically insightful explanation of the new prediction formula, we have reinvestigated our proposal using a wave propagation characteristic in a hollow rectangular waveguide, which clearly confirms our approach. By applying the proposed technique to an FPC antenna covered with a partially reflecting superstrate consisting of continuously tapered meander loops, we have proved that our method is very accurate and readily applicable to various types of FPC antennas with lateral walls. Experimental result confirms the validness of our approach.
Design of Broadband Quasi-Yagi Antenna Using a Folded Dipole Driver
Ta, Son Xuat ; Kim, Byoung-Chul ; Choo, Ho-Sung ; Park, Ik-Mo ;
Journal of electromagnetic engineering and science, volume 11, issue 3, 2011, Pages 227~233
DOI : 10.5515/JKIEES.2011.11.3.227
This paper describes the development of a broadband quasi-Yagi antenna using a folded dipole driver. The antenna is designed on a low-permittivity substrate to reduce the surface wave effect, and hence the gain can be enhanced easily by adding directors. The folded dipole driver is connected to a 50-
microstripline via a simple broadband microstrip-to-coplanar stripline transition with a quarter radial stub. The key motivation for the use of a folded dipole is to increase the input impedance at the driver, allowing a smaller mismatch loss between the antenna driver and the coplanar stripline feed. The proposed antenna has a measured bandwidth of 4.67~6.26 GHz for the -10 dB reflection coefficient, and a flat gain of 4.86~5.15 dB within the bandwidth.