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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of Korean Institute of Electromagnetic Engineering and Science
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The Korean Institute of Electromagnetic Engineering and Science
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Volume & Issues
Volume 21, Issue 12 - Dec 2010
Volume 21, Issue 11 - Nov 2010
Volume 21, Issue 10 - Oct 2010
Volume 21, Issue 9 - Sep 2010
Volume 21, Issue 8 - Aug 2010
Volume 21, Issue 7 - Jul 2010
Volume 21, Issue 6 - Jun 2010
Volume 21, Issue 5 - May 2010
Volume 21, Issue 4 - Apr 2010
Volume 21, Issue 3 - Mar 2010
Volume 21, Issue 2 - Feb 2010
Volume 21, Issue 1 - Jan 2010
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PAPR Reduction Method of OFDM System Using Fuzzy Theory
Lee, Dong-Ho ; Choi, Jung-Hun ; Kim, Nam ; Lee, Bong-Woon ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 21, issue 7, 2010, Pages 715~725
DOI : 10.5515/KJKIEES.2010.21.7.715
Orthgonal Frequency Division Multiplexing(OFDM) system is effective for the high data rate transmission in the frequency selective fading channel. In this paper we propose PAPR(Peak to Average Power Ratio) reduction method of problem in OFDM system used Fuzzy theory that often control machine. This thesis proposes PAPR reducing method of OFDM system using Fuzzy theory. The advantages for using Fuzzy theory to reduce PAPR are that it is easy to manage the data and embody the hardware, and required smaller amount of operation. Firstly, we proposed simple algorithm that is reconstructed at receiver with transmitted overall PAPR which is reduced PAPR of sub-block using Fuzzy. Although there are some drawbacks that the operation of the system is increased comparing conventional OFDM system and it is needed to send the information about Fuzzy indivisually, it is assured that the performance of the system is enhanced for PAPR reducing. To evaluate the perfomance, the proposed search algorithm is compared with the proposed algorithm in terms of the complementary cumulative distribution function(CCDF) of the PAPR and the computational complexity. As a result of using the QPSK and 16QAM modulation, Fuzzy theory method is more an effective method of reducing 2.3 dB and 3.1 dB PAPR than exiting OFDM system when FFT size(N)
Design of Inverted-F Antenna Using a Coupling Feed
Kim, Sang-Won ; Choi, Hak-Keun ; Park, Jae-Hyun ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 21, issue 7, 2010, Pages 726~733
DOI : 10.5515/KJKIEES.2010.21.7.726
This paper propose the printed inverted-F antenna using the coupling feed for the mobile phone. The coupling feed can normally leads the additional capacitances in the antenna, so the high inductive reactance of the antenna can be partly compensated. In this paper, it is shown that the bandwidth of the proposed antenna using the coupling feed is improved at
MHz. Then it is compared with the simple direct feed to confirm the improvement of the bandwidth. The proposed antenna covers GSM850/GSM950/DCS/USPCS/WCDMA/Wibro and has the maximum gain of －
dBi and shows omnidirectional patterns over the operating bands.
Analysis of Electromagnetic Pulse Coupling to Twisted Cable Using Chain Matrix
Cho, Jea-Hoon ; Lee, Jin-Ho ; Kim, Hyeong-Dong ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 21, issue 7, 2010, Pages 734~743
DOI : 10.5515/KJKIEES.2010.21.7.734
In this paper, we analyzed the EMP coupling for the nonuniform transmission lines, such as twisted cables, using the chain matrix algorithm and the multi-conductor analysis. The BLT method is widely used for the EMP coupling analysis of the transmission line, however, it is difficult to apply to the nonuniform transmission lines. In order to analyze the EMP coupling of nonuniform transmission lines, the whole nonuniform transmission line is divided into incremental uniform line sections of the finite numbers, and the coupling in each small sections is now summed up to get the EMP coupling effect of the entire nonuniform transmission line. To verify the proposed EMP coupling analysis method, the result of the EMP coupling simulation is compared with the solution of BLT equations for a uniform transmission line case. The proposed method is applied to the twisted cable over ground in case of being illuminated by the HEMP in order to analyze the EMP coupling.
Design of Multilayer Radome with Particle Swarm Optimization
Lee, Kyung-Won ; Hong, Ic-Pyo ; Park, Beom-Jun ; Chung, Yeong-Chul ; Yook, Jong-Gwan ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 21, issue 7, 2010, Pages 744~751
DOI : 10.5515/KJKIEES.2010.21.7.744
In this paper, the design of multilayer radome within, the insertion loss, －0.3 dB in X-band with PSO was carried out based on two cases. The first is that, deciding material constant of skin and core, each layer thickness of c-sandwich radome with PSO is found and the second is that, deciding material constant and thickness of the skins of both sides, the material constant and thickness of three layers between skins of both sides using PSO is decided. The performance of the designed radome almost agreed with the required performance. It was showed that the radome design applying PSO algorithm is easy and fast and the optimum radome is also designed in combination of the various parameters of radome. From these results, the radome having various performance can be designed except the tedious calculation and also be applied to various radome structure.
Interference Analysis of RFID Gen-2 System Considering Both PHY and MAC Layers
Yoon, Hyun-Goo ; Choi, Sun-Woong ; Jang, Byung-Jun ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 21, issue 7, 2010, Pages 752~760
DOI : 10.5515/KJKIEES.2010.21.7.752
This paper investigates the performance of EPCglobal Generation-2(Gen-2) radio frequency identification(RFID) protocol under reader-to-reader interfering environments. We establish a modified discrete-time Markov chain(DTMC) model for the Gen-2 and accordingly obtain quantitative results of query success rate(QSR) and tag identification speed (TIS). Extensive simulations validate our theoretical analysis and demonstrate that the number of tags over 100 has little impact on the performance. TIS linearly decreases by 10 tags/sec/reader as the number of interfering readers increases. Our model for Gen-2 protocol is also useful to study the performance of other RFID protocols.
Analysis on Spectral Regrowth of Bandwidth Expansion Module by Quadrature Modulation Error in Digital Chirp Generator
Kim, Se-Young ; Sung, Jin-Bong ; Lee, Jong-Hwan ; Yi, Dong-Woo ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 21, issue 7, 2010, Pages 761~768
DOI : 10.5515/KJKIEES.2010.21.7.761
This paper presents an effective method to achieve the wideband waveform for high resolution SAR(Synthetic Aperture Radar) using the frequency multiplication technique. And also this paper analyzes the root causes for the spectral regrowth due to 3rd-order intermodulation in chirp bandwidth expansion scheme using quadrature modulator and frequency multipliers. The amplitude and phase imbalance requirement are defined based on the simulation results in terms of quadrature channel imbalance. This minimizes the degradation of range resolution, peak sidelobe ratio and integrated sidelobe ratio. The wideband chirp generator using the frequency multiplier and memory map scheme was manufactured and the compensation technique was presented to reduce the spectral regrowth of SAR waveform by minimizing the amplitude and phase imbalance. After I and Q channel imbalance adjustment, the carrier level reduces －28.7 dBm to －53.4 dBm. Chirp signal with 150 MHz bandwidth at S-band expands to 600 MHz bandwidth at X-band. The sidelobe levels are reduced by about 8 to 9 dB by compensating the amplitude balance between I and Q channels.
A Polarization-Switchable Microstrip Patch Antenna Using Corner Slots on Ground Plane and PIN Diodes
Park, Chul-Woo ; Lee, Tae-Hak ; Choi, Jun-Ho ; Yoon, Won-Sang ; Pyo, Seong-Min ; Kim, Young-Sik ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 21, issue 7, 2010, Pages 769~777
DOI : 10.5515/KJKIEES.2010.21.7.769
In this paper, a switchable circularly polarized microstrip patch antenna using PIN diodes and corner slots on ground plane is proposed at 2.4 GHz. The proposed antenna has a square microstrip patch and ground plane that consists of two pair of slots and PIN diodes. The electrical lengths of the slots are adjusted by using the switching characteristic of the PIN diode, so the polarization of the proposed antenna can be switchable between linear, left-handed(LH) and right-handed(RH). By separating the ground plane for the DC bias, the size reduction effect is also obtained. When the proposed antenna is operated as linear polarization, the return loss and impedance bandwidth are 15 dB, 59 MHz, and when operated as LH and RH polarization, the minimum axial ratio and 3-dB axial ratio bandwidth are 1.17 dB, 1.67 dB, 28 MHz, and 32 MHz, respectively.
Design of Dual-Band Monopole Antenna Fed-by CPW Using Asymmetric Ground Plane
Lee, Sang-Min ; Kim, Nam ; Lee, Seung-Woo ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 21, issue 7, 2010, Pages 778~785
DOI : 10.5515/KJKIEES.2010.21.7.778
The folded monopole antenna for applying mobile communications equipment and wireless devices is presented in this paper. By using the coplanar waveguide feed the operating bandwidth has improved. In addition, each individual resonant elements has occurred different capacitance through asymmetrical left and right ground planes; therefore, the bandwidth has kept and the impedance matching has stabilized. By measurement results, the impedance bandwidth under VSWR< 2.5:1 are
MHz and the
MHz, also radiation patterns has omni-directional characteristics. The maximum gains of the proposed antenna are 5.52, 0.64, 3.00, 0.94 and 1.85 dBi at 850, 1,575, 1,790, 1,930 and 2,050 MHz respectively. The proposed antenna will be adapted to the internal antenna of the mobile communication devices.
EBG Structure Using Bridge Line in the Signal Transmission Plane
Kim, Byung-Ki ; Ha, Jung-Rae ; Lee, June-Sang ; Bae, Hyeon-Ju ; Kwon, Jong-Hwa ; Nah, Wan-Soo ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 21, issue 7, 2010, Pages 786~795
DOI : 10.5515/KJKIEES.2010.21.7.786
In this paper, we propose a new EBG structure that the two unit cells are connected by the bridge line in signal transmission plane. The SSN of the power plane is reduced effectively by via holes and bridge lines connecting the unit cells. The superior signal transfer characteristic is shown between the signal lines in the signal transmission plane. The proposed EBG structure contains 1.2 GHz cut-off frequency and less than －30 dB suppression in the 8.3 GHz broad bandwidth. In addition, To improve the SI(Signal Integrity) in signal transmission plane keeping the same bandstop frequency range, the optimized location of the reference plane is proposed.
FH DFT-Spreading OFDM System for the Effective Channel Estimation and PAPR Reduction in Jamming Channel
Kim, Jang-Su ; Ryu, Heung-Gyoon ; Lee, Seung-Jun ; Ko, Dong-Kuk ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 21, issue 7, 2010, Pages 796~804
DOI : 10.5515/KJKIEES.2010.21.7.796
It is important to use the comb type pilot allocation for the continuous channel and efficient processing. And DFT-spreading OFDM is used a lot to solve high PAPR problem of OFDM system. However, PAPR is increased again when comb type pilot is used to estimate channel characteristics. So, in this paper, we employ a new SLM method to DFT-spreading OFDM system to reduce increased high PAPR. And we suggest an effective method to transmit side information without additional bandwidth. Pilot and side information must be preserved from jamming or intentional interferences since those are very important in DFT spread OFDM system using SLM. So, in this paper, we like to analyze and simulate the performance of DFT spread OFDM system based on SLM against jamming signal. To remedy the vulnerable shortcomings of DFT spread OFDM about jamming or intentional interferences, we employ FH(Frequency Hopping) method and analyze system performance under the several jamming conditions such as MTJ(Multi Tone Jamming) and PBJ(Partial Band Jamming).
2D Crank-Nicolson FDTD Method Based on Isotropic-Dispersion Finite Difference Equation for Lossy Media
Kim, Hyun ; Koh, Il-Suek ; Yook, Jong-Gwan ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 21, issue 7, 2010, Pages 805~814
DOI : 10.5515/KJKIEES.2010.21.7.805
The Crank-Nicolson isotropic-dispersion finite difference time domain(CN ID-FDTD) scheme is proposed based on isotropic-dispersion finite difference(ID-FD)
. The dispersion relation of CN ID-FDTD is derived for lossy media by solving the eigenvalue problem of iteration matrix in spatial spectral domain, in addition, the weighting factors and scaling factors of the CN ID-FDTD scheme are presented for low dispersion error. The CN ID-FDTD scheme makes the dispersion error drastically reduced and shows accurate numerical results compared to the conventional Crank-Nicolson FDTD method.
Cooperative Relaying Scheme Using Multiple Relays in Two-Way Relay Network
Park, Ji-Hwan ; Kong, Hyung-Yun ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 21, issue 7, 2010, Pages 815~822
DOI : 10.5515/KJKIEES.2010.21.7.815
Two-way relaying scheme based on relay selection can not only achieve higher rate but also get the selection diversity gain according to the number of relays. However the scheme can not achieve combining gain because it does not consider the direct link between users. In this paper, we propose, with multiple relays, opportunistic cooperative two-way relaying scheme and incremental cooperative two-way relaying scheme which can achieve both selection diversity gain and combining gain. Simulation results show that proposed scheme outperform the conventional scheme by achieving both combining gain and selection diversity gain according to the number of relays.
Circularly Polarized Wave Generating Coaxial to Waveguide Transition for Horn Antenna
Lee, Kwang-Jae ; Woo, Duk-Jae ; Lee, Taek-Kyung ; Lee, Jae-Wook ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 21, issue 7, 2010, Pages 823~830
DOI : 10.5515/KJKIEES.2010.21.7.823
This paper deals with a coaxial-to-waveguide transition generating circularly polarized wave to be connected with horn antennas. By combining vertical coaxial fed structure, back-short and the polarization twisting structure, the circular polarization is successfully generated in the waveguide. The designed and implemented transition shows that the present structure can significantly reduce the size of the antenna part at X-band.
Design of Vertical Type MEMS Probe with Branch Springs
Ha, Jung-Rae ; Kim, Jong-Min ; Kim, Byung-Ki ; Lee, June-Sang ; Bae, Hyeon-Ju ; Kim, Jung-Yup ; Lee, Hak-Joo ; Nah, Wan-Soo ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 21, issue 7, 2010, Pages 831~841
DOI : 10.5515/KJKIEES.2010.21.7.831
The conventional vertical probe has the thin and long signal path that makes transfer characteristic of probe worse because of the S-shaped structure. So we propose the new vertical probe structure that has branch springs in the S-shaped probe. It makes closed loop when the probe mechanically connects to the electrode on a wafer. We fabricated the proposed vertical probe and measured the transfer characteristic and mechanical properties. Compared to the conventional S-shaped vertical probe, the proposed probe has the overdrive that is 1.2 times larger and the contact force that is 2.5 times larger. And we got the improved transfer characteristic by 1.4 dB in
GHz. Also we developed the simulation model of the probe card by using full-wave simulator and the simulation result is correlated with measurement one. As a result of this simulation model, the cantilever probe and PCB have the worst transfer characteristic in the probe card.
Circularly Polarized Antenna with Wide Axial-Ratio Bandwidth
Lee, Kwang-Jae ; Woo, Duk-Jae ; Lee, Taek-Kyung ; Lee, Jae-Wook ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 21, issue 7, 2010, Pages 842~849
DOI : 10.5515/KJKIEES.2010.21.7.842
This paper deals with a TT&C circularly polarized turnstile antenna for LEO satellites. The turnstile antenna consists of radiator for radiating power to free-space and power divider for generating circularly polarized wave. we presents a radiator to tolerate in space environments and a power divider to provide flat phase difference at wide bandwidth. The bandwidth of the proposed antenna covers the frequency bands of up- and down-link. The antenna shows wide beamwidth and enhanced axial ratio for unfavorable space environments.