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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 26, Issue 12 - Dec 2015
Volume 26, Issue 11 - Nov 2015
Volume 26, Issue 10 - Oct 2015
Volume 26, Issue 9 - Sep 2015
Volume 26, Issue 8 - Aug 2015
Volume 26, Issue 7 - Jul 2015
Volume 26, Issue 6 - Jun 2015
Volume 26, Issue 5 - May 2015
Volume 26, Issue 4 - Apr 2015
Volume 26, Issue 3 - Mar 2015
Volume 26, Issue 2 - Feb 2015
Volume 26, Issue 1 - Jan 2015
Selecting the target year
Measurement of Noise Parameters Using 6-Port Network (Invited Paper)
Yeom, Kyung-Whan ; Ahmed, Abdule-Rahman ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 26, issue 2, 2015, Pages 119~126
DOI : 10.5515/KJKIEES.2015.26.2.119
The information about noise parameters is essential in the design of low noise amplifier. In the past, the noise parameters were measured using an impedance tuner and noise figure analyzer. Recently, the authors proposed the method of measuring the noise parameters using the 8-port network without the aid of the mechanically driven impedance tuner. However, the 8-port method still requires the noise source and causes the complexity in the measurements. In this paper, a novel measurement method of the noise parameters without the noise source using 6-port network is proposed. Based on the proposed 6-port method, the noise parameters of 10 dB attenuator whose noise parameters can be theoretically determined were measured and the measured noise parameters are compared with those measured using the previous 8-port network method. As a result, the accuracy of the measured noise parameters using 6-port network is found to be comparable to the previous 8-port network method.
2.6 GHz-Band MIMO Omni Antenna Having Folded Configuration
Lee, Su-Won ; Lee, Jae-Du ; Lee, Hai-Young ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 26, issue 2, 2015, Pages 127~134
DOI : 10.5515/KJKIEES.2015.26.2.127
In this paper, we propose 2.6 GHz single band dual polarization MIMO omni antenna for in-building applications. The proposed antenna operates at 2.6 GHz single LTE band, Up-link 2.52~2.54 GHz and Down-link 2.64~2.66 GHz. Horizontal and vertical polarizations of the antenna has been, respectively, constructed by the synthesis of four folded loop antennas and the folded monopole antenna. The height of the MIMO omni-directional antenna is minimized to be less than
from the ground. The measurement results show excellent MIMO omni antenna performance of 2.85 dBi vertical polarization gain, 2.29 dBi horizontal polarization gain, and 19.25 dB port isolation.
Prediction of Impedance Characteristics of Multi-Layer Ceramic Capacitor Based on Coupled Transmission Line Theory
Jeon, Jiwoon ; Kim, Jonghyeon ; Pu, Bo ; Zhang, Nan ; Song, Seungjae ; Nah, Wansoo ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 26, issue 2, 2015, Pages 135~147
DOI : 10.5515/KJKIEES.2015.26.2.135
With the miniaturization and digitalization of electronics industry, demand for Multi-Layer Ceramic Capacitor(MLCC) has increased steadily because of its various applications such as DC Blocking, Decoupling and Filtering etc. The modeling techniques of MLCC has been studied for a long time but most of these modeling method can only be applied after measurement and this has some losses of material, time in both production stage and measurement stage. This paper proposes the modeling method which can predict the frequency characteristics of MLCC from structure data and material data in design stage. The impedance of N-Layer Capacitor can be expressed in differential mathematical form based on coupled transmission line equations. By using this formula, we can predict the impedance of MLCC. As a result, proposed modeling is correspond with simulation, and it takes much less time to obtain the result than the simulation.
Compact S-Band Antenna Hat for RF Compatibility Testing of Launch Vehicle
Kim, Sung-Wan ; Park, Dong-Chul ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 26, issue 2, 2015, Pages 148~157
DOI : 10.5515/KJKIEES.2015.26.2.148
In this paper, we propose a compact antenna hat to perform RF compatibility testing efficiently between the launch vehicle and ground stations. The proposed structure implements a small size and low loss using the conductive shield instead of the conventional RF absorber. The S-band antenna hat, which is fabricated for an inverted-F onboard antenna with the size of
, has the small enclosure of
, the return loss of 25.6 dB, the insertion loss of 0.26 dB, and the leakage loss of 49.4 dB at the center frequency of 2.25 GHz. The simulated and measured results show a good agreement.
A Design of Mode-Coupler with a Pair of Slots for Ka Band Multi-Mode Monopulse Tracking System
Kwon, Kun-Sup ; Heo, Jong-Wan ; Hwang, Ki-Min ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 26, issue 2, 2015, Pages 158~164
DOI : 10.5515/KJKIEES.2015.26.2.158
The main mission of OTM(On-The-Move) satellite communication system is to provide satellite communication service while moving on a vehicle. So it should have a capability to maintain a reliable communication channel when it travels at high speeds or in a severe fluctuation region. This paper presents a small-sized multi-mode monopulse structure applicable to OTM satellite communication system which has only single mode-coupler with a pair of slot using a feature of circular polarized received signal. And tracking error signal is defined using fundamental and high-order modes.
S-Band Low Noise Amplifier Based on GaN HEMT for High Input Power Robustness
Kim, Hong-Hee ; Kim, Sang-Hoon ; Choi, Jin-Joo ; Choi, Gil-Wong ; Kim, Hyoung-Joo ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 26, issue 2, 2015, Pages 165~170
DOI : 10.5515/KJKIEES.2015.26.2.165
In this paper, we present design and measurement of LNA(Low Noise Amplifier) based on GaN HEMT(Gallium Nitride High Electron Mobility Transistor) to reduce the total noise figure of radar receiver and for robustness of LNA. In radar receiver using LNA based on GaAs(Gallium Arsenide) technology, limiter is necessary at the very front of the radar receiver to protect LNA. As a result, total noise figure of radar receiver is deteriorated. In this research, measured noise figure of LNA based on GaN HEMT is below 2 dB. In the case of commercialized GaAs LNA, recommended maximum input power is about 30 dBm. On the other hand, GaN HEMT LNA which is designed and measured is burned-out when input power is 43 dBm and robustness is guaranteed at input power 45.4 dBm.
Compatibility between LTE Cellular Systems and WLAN
Jo, Han-Shin ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 26, issue 2, 2015, Pages 171~178
DOI : 10.5515/KJKIEES.2015.26.2.171
3GPP long-term evolution(LTE) band 2.3~2.4 GHz is adjacent to 2.4~2.5 GHz band for WLAN, and therefore compatibility study of the two systems is desirable. We propose a dynamic system simulation methodology to investigate the effect of WLAN interference on LTE systems. As capturing space/time/frequency changes in system parameters, the dynamic system simulation can exactly predict real system performance. Using the proposed methodology, we obtain LTE downlink throughput loss for the frequency separation between the two systems. Throughput loss under 1 % is obtained from guard band over 11 MHz(single channel allocation) or 10 MHz(three channel allocation).
A Study on the Methods to Simulate the Target Reflective Signal in a Wideband Radar
Kim, EunHee ; Kim, TaeHyung ; Kim, Sun-Ju ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 26, issue 2, 2015, Pages 179~188
DOI : 10.5515/KJKIEES.2015.26.2.179
Testing a radar system in real environment requires a lot of time and cost. Thus various target simulators are developed to evaluate the radar performance and its functions as well. In order to enhance the range resolution and the accuracy for tracking, recent radar system tends to use the wideband signal. In this paper, we summarize two target simulation methods - the direct sampling method with the digital memories and the beat frequency generation for the stretch processing - and suggest the condition to improve their performance for a wideband radar system.
Generation of ISAR Image for Realistic Target Model Using General Purpose EM Simulators
Kim, Seok ; Nikitin, Konstantin ; Ka, Min-Ho ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 26, issue 2, 2015, Pages 189~195
DOI : 10.5515/KJKIEES.2015.26.2.189
There are many research works on the SAR image generation using EM(Electro Magnetic) simulation. Particularly, there are several dedicated S/Ws for SAR image generation and analysis. But, most of them are not available to the public due to the reason for defense and security. In this paper, we describe the generation of ISAR images for a realistic target model using the general purpose EM simulator like FEKO. This method can benefit us many advantages like building the database of many targets for target recognition with cost-and-time effective way.
Comparison of Scattering Characteristics between Cylindrical Infinite and Finite Periodic Structure
Jeong, Yi-Ru ; Hong, Ic-Pyo ; Lee, Kyung-Won ; Kok, Chan-Ho ; Kim, Dae-Whan ; Yook, Jong-Gwan ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 26, issue 2, 2015, Pages 196~203
DOI : 10.5515/KJKIEES.2015.26.2.196
In order to apply cylindrical periodic array to phased array antenna or frequency selective surface, efficient electromagnetic analysis is required. Finite periodic array is applied in real situation. But, generally, assumed that periodic structure is arranged infinitely, approximate electromagnetic characteristics can be obtained efficiently. But, difference of characteristics between real structure and approximate structure occurs because finite periodic array is approximated to infinite periodic array. Therefore, comparison and analysis of cylindrical infinite array and finite array are required. In this paper, cylindrical infinite periodic array are analyzed using cylindrical Floquet harmonics. Also, cylindrical finite periodic array is analyzed using method of moments (MoM) with thin wire approximation because periodic structures which are composed of strip with narrow width are analyzed. Transmission characteristics and surface currents of infinite and finite periodic structures are compared.
An Analysis on Harmonic Effects of Wideband Stepped Frequency Radars
Jun, Seung-Hyun ; Kim, Dong-Kyoo ; Lee, Chang-Seok ; Lee, Dong-Ho ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 26, issue 2, 2015, Pages 204~212
DOI : 10.5515/KJKIEES.2015.26.2.204
Harmonic effects in a wideband stepped frequency radar(650 MHz~4.5 GHz) have been analyzed. As a result of numerical analysis and simulation, when the second harmonic exists in each frequency, a time-domain result represents an additional object which does not exist but looks to be located at a distance of twice the original object distance. The second harmonics can be removed effectively by low pass filters because there are no other signals between DC and a fundamental signal. In this paper, the harmonic problem can be solved by removing the second harmonics of 650 MHz to 4.5 GHz wideband fundamental signal with two switches and four low pass filters.
Microwave Photonic Filter Using Optical True-Time-Delay Line Matrix
Jung, Byung-Min ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 26, issue 2, 2015, Pages 213~217
DOI : 10.5515/KJKIEES.2015.26.2.213
Microwave Photonic(MWP) filters capable of use a bandpass filter or a notch filter with large bandwidth have been proposed. 4-lines
2-bit fiber-optic delay lines with a unit time-delay difference of 50 ps were experimentally realized. By changing the time-delay difference and the coefficients of microwave-modulated optical signals, the bandpass and notch filters were implemented and characterized.
Inter-Pulse Motion Compensation of an ISAR Image Generated by Stepped Chirp Waveform Using Improved Particle Swarm Optimization
Kang, Min-Seok ; Lee, Seong-Hyeon ; Park, Sang-Hong ; Shin, Seung-Yong ; Yang, Eunjung ; Kim, Kyung-Tae ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 26, issue 2, 2015, Pages 218~225
DOI : 10.5515/KJKIEES.2015.26.2.218
Inverse synthetic aperture radar(ISAR) is coherent imaging system formed by conducting signal processing of received data which consists of radar cross section(RCS) reflected from maneuvering target. A novel algorithm is proposed to compensate inter-pulse motion(IPM) for the purpose of forming an well-focused ISAR image through signals generated by stepped chirp waveform( SCW). The velocity and acceleration of the target related to IPM are estimated based on particle swarm optimization (PSO) which has been widely used in optimization technique. Furthermore, a modified PSO which enables us to improve the performance of PSO is used to compensate IPM in a very short-time. Simulation results using point scatterer model of a Boeing-737 aircraft validate the performance of the proposed algorithm.