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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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Journal DOI :
The Korean Institute of Electromagnetic Engineering and Science
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Volume & Issues
Volume 25, Issue 12 - Dec 2014
Volume 25, Issue 11 - Nov 2014
Volume 25, Issue 10 - Oct 2014
Volume 25, Issue 9 - Sep 2014
Volume 25, Issue 8 - Aug 2014
Volume 25, Issue 7 - Jul 2014
Volume 25, Issue 6 - Jun 2014
Volume 25, Issue 5 - May 2014
Volume 25, Issue 4 - Apr 2014
Volume 25, Issue 3 - Mar 2014
Volume 25, Issue 2 - Feb 2014
Volume 25, Issue 1 - Jan 2014
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Efficiency Improvement of Power Amplifier Using a Digitally-Controlled Dynamic Bias Switching for LTE Base Station
Seo, Mincheol ; Lee, Sung Jun ; Park, Bonghyuk ; Yang, Youngoo ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 25, issue 8, 2014, Pages 795~801
DOI : 10.5515/KJKIEES.2014.25.8.795
This paper presents an efficiency enhancement for the high power amplifier using DDBS(Digitally-controlled Dynamic Bias Switching) method which dynamically provides the power amplifier with two bias voltage levels according to the input envelope signal. It is quite easy to adjust the control signal by using a digital processing. The fabricated DDBS PA was evaluated using an 64 QAM FDD LTE signal, which has a center frequency of 2.6 GHz, a bandwidth of 10 MHz and a PAPR of 9.5 dB. The DDBS increases the power amplifier`s PAE(Power-Added Efficiency) from 40.9 % to 48 %, at an average output power level of 43 dBm.
Study for the Uncertainty Estimation of Output Power under the Mismatch Condition of Power Amplifiers
Lee, Garam ; Park, Youngcheol ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 25, issue 8, 2014, Pages 802~807
DOI : 10.5515/KJKIEES.2014.25.8.802
In this paper, an accurate method to estimate the measurement uncertainty of a power amplifier was proposed. Because power amplifiers incorporate mismatch at the drain for the optimal performance, the general method is not enough to produce precise measurement uncertainty of the output power. In order to supplement this method, We suggest comprehensive power measurement uncertainty which is utilized by a complex reflection coefficient and measurement uncertainty of S-parameter which contain the mismatch at the drain on the power amplifier. After that, we compared it with real measurement results of the 10 watt power amplifier which operates on 3.7 GHz. As a result, suggested measurement uncertainty could obtain the uncertainty of output power near 10 times accurate in comparison with existing uncertainty calculation method.
Measurement of the Noise Parameters of On-Wafer Type DUTs Using 8-Port Network
Lee, Dong-Hyun ; Ahmed, Abdule-Rahman ; Lee, Sung-Woo ; Yeom, Kyung-Whan ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 25, issue 8, 2014, Pages 808~820
DOI : 10.5515/KJKIEES.2014.25.8.808
In this paper, we fabricated two on-wafer type DUT(Device-Under-Test)s; a 10-dB attenuator and an amplifier using commercially available MMIC and we proposed the measurement method of the noise parameters for the two fabricated DUTs. Since the 10-dB attenuator DUT is a passive device, its noise parameters can be accurately determined when its S-parameters are measured. In the case of the amplifier DUT, its noise parameters are available in the datasheet. Hence, the measured noise parameters using the proposed method can be assessed by comparing with the known noise parameters. The noise parameter measurement method having been presented by the authors requires the S-parameters of the 8-port network used in the measurement and limited to coaxial type DUTs. When on-wafer probes are included in the 8-port network, the 8-port S-parameters requires the measurements with different kinds of connectors. In this paper, we obtained the 8-port S-parameters using the Smart-Cal function in the network analyzer. The measured noise parameters shows about
. Other noise parameters with the frequency change show good agreement with the expected results.
Spectrum Access Model Proposal for Frequency Sharing in 3~4 GHz
Kang, Young-Heung ; Lee, Dae-Young ; Park, Duk-Kyu ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 25, issue 8, 2014, Pages 821~827
DOI : 10.5515/KJKIEES.2014.25.8.821
Many researches on the usage of shared spectrum have continuously been carried out to solve the recent frequency shortage problem and to use efficiently the spectrum without interference. Also, exponential mobile data growth and the solutions needed to address this challenge are parallel key objectives addressed in many countries. Spectrum policy innovation to meet this challenge is the ASA/LSA (Authorized Shared Access/Licensed Shared Access), which is the best access model to employ the small cell technology to meet this mobile traffic growth. Because 3.5 GHz bands is considered as the ASA/LSA frequency, in this paper, we propose the SAM(Spectrum Access Model) in 3~4 GHz bands to estimate the available ASA/LSA bands and to open more free spectrum. These results are utilized as the data to develop the SAM for the small cell and the open frequency in future.
Analysis of Radio Spectrum Policy for the Creative Usage of Radio Waves
Kim, Chang-Joo ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 25, issue 8, 2014, Pages 828~837
DOI : 10.5515/KJKIEES.2014.25.8.828
With the rapid development of radio technologies, there have been actively researching the convergence between radio technology and other industry as well as wireless communications itself. In this paper, we investigate the paradigm shift of radio policy as radio technologies such as small cells and cognitive radio advance, and analyze the directions of spectrum policy and radio technology to promote the creative use of radio waves. In particular, we propose the spectrum policy for the expansion of open spectrum policy, technology development of interference management, and restructuring of the Korean radio law.
Simulation Study of Altitude and Angle Estimation with an InSAR Altimeter
Paek, Inchan ; Lee, Sangil ; Chun, Joohwan ; Lee, Hyukjung ; Jang, Jong Hun ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 25, issue 8, 2014, Pages 838~848
DOI : 10.5515/KJKIEES.2014.25.8.838
We present a simulation study of an algorithm for the range and angle of arrival(AOA) estimation with an interferometric synthetic aperture radar(InSAR) altimeter using a real digital elevation model(DEM). We also illustrate a step-by-step procedure of generating raw InSAR data, as well as their range and azimuth compressed data, which is to be used for the subsequent altitude and angle estimation. The AOA is estimated using a deterministic maximum likelihood estimator(DMLE) applied to the first arrived point for each pulse in the compressed data obtained with three antennas. The range bin size and the pulse repetition interval(PRI) are much smaller than the cell size of the DEM used in this study. To make the DEM compatible to the radar parameters, we first generate a higher resolution DEM by linearly interpolating the given DEM. After a brief description of the principle of the InSAR altimeter, the algorithms for altitude and angle estimation are presented, and their performance is assessed through simulation.
A Study of Efficient CFAR Algorithm
Shin, Sang-Jin ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 25, issue 8, 2014, Pages 849~856
DOI : 10.5515/KJKIEES.2014.25.8.849
This paper proposes a new efficient CFAR algorithm. The structure of the proposed CFAR is relatively simple as compared with the OS-CFAR or ML-CFAR which are considered to deal with the nonhomogeneous environment such as clutter and multiple targets. The proposed algorithm is effectively applied to the radar signal processor with reduced computation burden. The relationship between the threshold and PFA of the proposed CFAR is derived analytically. The CFAR loss of the proposed CFAR algorithm is compared with CA-CFAR and OS-CFAR based on both SNR and ADT(Average Detection Threshold).
Time Dependent Interaction between Electromagnetic Wave and Dielectric Barrier Discharge Plasma Using Fluid Model
Kim, Yuna ; Oh, Il-Young ; Jung, Inkyun ; Hong, Yongjun ; Yook, Jong-Gwan ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 25, issue 8, 2014, Pages 857~863
DOI : 10.5515/KJKIEES.2014.25.8.857
In determining interaction between plasma and electromagnetic wave, plasma frequency and collision frequency are two key parameters. They are derived from electron density and temperature, which vary in an extremely wide range, depending on a plasma generator. Because the parameters are usually unknown, traditional researches have utilized simplified electron density model and constant electron temperature approximation. Introduction of plasma fluid model to electromagnetics is suggested to utilize relatively precise time dependent variables for given generator. Dielectric barrier discharge(DBD) generator is selected due to its simple geometry which allows us to use one dimensional analysis. Time dependent property is analyzed when microwave is launched toward parallel plate DBD plasma. Afterwards, attenuation tendency with the change of electron density and temperature is demonstrated.
Beam Curve Optimization for Minimizing the Phase Errors of Rotman Lens
Park, Joo-Rae ; Park, Dong-Chul ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 25, issue 8, 2014, Pages 864~871
DOI : 10.5515/KJKIEES.2014.25.8.864
In this paper, we propose an optimization method for obtaining beam curve which minimize the phase errors of Rotman lens. This method is based on idea that 3 path lengths from a beam port through equal phase points, which consist of the center point of array antenna and two points placed symmetrically or asymmetrically along array antenna, to the corresponding phase front are equal. According to this method, the optimal locations of beam ports can be obtained directly by finding each equal phase point set on array antenna to minimize the phase errors for each beam direction. Simulation results show that the proposed method is the most optimal and effective method for determining the beam curve of Rotman lens with low phase errors.
Method for Measurement of Complex Relative Permittivity of Semi-Solid Materials Using Novel Cavity Resonator Design
Park, Rae-Seoung ; Jang, Jihyun ; Park, Byungdeok ; Kim, Junhwan ; Park, Sangbok ; Chung, Young-Seek ; Cheon, Changyul ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 25, issue 8, 2014, Pages 872~878
DOI : 10.5515/KJKIEES.2014.25.8.872
This paper proposes a measurement method of the complex relative permittivity of semi-solid materials using a new cavity structure. Semi-solid materials are positioned in the proposed cavity where an aperture exists on each corner of the upper part and a ground plane is separated. In order to show the validation of the proposed method, we measured the complex relative permittivity of distilled water and 0.9 % saline by sensing a shift of resonant frequency and using Critical-Points Method, and compared the results with those derived from the Cole-Cole equation.