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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of electromagnetic engineering and science
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Journal DOI :
The Korean Institute of Electromagnetic Engineering and Science
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Volume & Issues
Volume 10, Issue 4 - Dec 2010
Volume 10, Issue 3 - Sep 2010
Volume 10, Issue 2 - Jun 2010
Volume 10, Issue 1 - Mar 2010
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Approximate Numerical Reflection Coefficient of Isotropic-Dispersion Finite-Difference Time-Domain(ID-FDTD) Scheme at the Planar Dielectric Interface for the TM Wave
Deng, Pingping ; Koh, Il-Suek ;
Journal of electromagnetic engineering and science, volume 10, issue 2, 2010, Pages 45~49
DOI : 10.5515/JKIEES.2010.10.2.045
This paper presents an analytical formulation of the numerical reflection coefficient of the ID-FDTD scheme at the planar dielectric boundary for a TM wave incidence. The reflection coefficient is formulated in an approximate manner, and the accuracy of this method is numerically verified. The effective dielectric constant for a grid on the interface is obtained, and then reduced to that of the Yee scheme for a small cell size.
Joint Subcarrier Matching, Power Allocation and Bit Loading in OFDM Dual-Hop Systems
Kong, Hyung-Yun ; Lee, Jin-Hee ;
Journal of electromagnetic engineering and science, volume 10, issue 2, 2010, Pages 50~55
DOI : 10.5515/JKIEES.2010.10.2.050
Orthogonal Frequency Division Multiplexing(OFDM) dual-hop systems can take full advantages of the techniques of both multi-hop communication and OFDM. To achievethis end, we propose a joint subcarrier matching, power allocation and bit loading algorithm operating under a total power constraint and the same Bit Error Rate(BER) threshold over all subcarriers. Simulation results demonstrated system throughput improvement compared to single-hop systems and dual-hop systems with different bit loading algorithms for each relay position, power constraint, and required BER.
An Efficient Space-Time Coded Cooperation Protocol for Wireless Communication
Park, Ji-Hwan ; Kong, Hyung-Yun ;
Journal of electromagnetic engineering and science, volume 10, issue 2, 2010, Pages 56~60
DOI : 10.5515/JKIEES.2010.10.2.056
This paper proposes a new cooperative protocol in which Alamouti`s scheme is applied to exploit the advantages of both coded cooperation and Alamouti`s scheme. It not only has better than direct transmission but also coded cooperation at appropriate cooperation levels. Simulation results show that the proposed protocol can save approximately 6~7 dB of transmit power to achieve the target BER(Bit Error Rate) compared with coded cooperation. Furthermore, the performance of the proposed protocol does not significantly depend on the qualities of inter-user channels.
Numerical Analysis of Back Scattering from a Target over a Random Rough Surface Using DRTM
Yoon, Kwang-Yeol ;
Journal of electromagnetic engineering and science, volume 10, issue 2, 2010, Pages 61~66
DOI : 10.5515/JKIEES.2010.10.2.061
This paper is concerned with an analysis of the back scattering of electromagnetic waves from a target moving along random rough surfaces such as the desert, and sea. First, the discrete ray tracing method(DRTM) is introduced, and then, this method is applied to the back scattering problem in order to investigate the effect of the back scattering from random rough surfaces on the electric field intensities. Finally, numerical examples of various height deviations of the Gaussian type of rough surfaces are shown. It is numerically demonstrated that the back scattering is dominated by the diffractions related to the reflections from the random rough surfaces.
Design of a Three Dimensional Folded Monopole Antenna Using Current Flow
Liu, Yulin ; Lee, Seung-Woo ; Kim, Nam ;
Journal of electromagnetic engineering and science, volume 10, issue 2, 2010, Pages 67~72
DOI : 10.5515/JKIEES.2010.10.2.067
A new type of monopole antenna whit broadband characteristics is presented in this article. To reduce the size of the antenna, its upper part is folded. By separating the current flow, the resonance in the shorter part is in the higher band; and the longer part resonates in the lower band. This gives the broadband characteristics of the antenna. Slots on the corner using an oblique line improve the impedance matching and bandwidth. The measurement results show that the bandwidth operates from 0.848~0.992 GHz and 1.744~2.528 GHz, and the radiation patterns are in an omni-directional shape.
A Research on the Magnitude/Phase Asymmetry Measurement Technique of the RF Power Amplifier Based on the Predistortive Tone Cancellation Technique
Choi, Heung-Jae ; Shim, Sung-Un ; Kim, Young-Gyu ; Jeong, Yong-Chae ; Kim, Chul-Dong ;
Journal of electromagnetic engineering and science, volume 10, issue 2, 2010, Pages 73~77
DOI : 10.5515/JKIEES.2010.10.2.073
This paper proposes a novel memory effect measurement technique in RF power amplifiers(PAs) using a two-tone intermodulation distortion(IMD) signal with a very simple and intuitive algorithm. Based on the proposed predistortive tone cancellation technique, the proposed measurement method is capable of measuring the relative phase and magnitude of the third-order and fifth-order IMDs, as well as the fundamental signal. The measured relative phase between the higher and lower IMD signal for specific tone spacing can be interpreted as the group delay(GD) information of the IMD signal concerned. From the group delay analysis, we can conclude that an adaptive control of GD as well as the magnitude and phase is a key function in increasing the linearization bandwidth and the dynamic range in a predistortion(PD) technique.