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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
Journal Basic Information
Journal DOI :
The Korean Institute of Electromagnetic Engineering and Science
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Volume & Issues
Volume 18, Issue 12 - Dec 2007
Volume 18, Issue 11 - Nov 2007
Volume 18, Issue 10 - Oct 2007
Volume 18, Issue 9 - Sep 2007
Volume 18, Issue 8 - Aug 2007
Volume 18, Issue 7 - Jul 2007
Volume 18, Issue 6 - Jun 2007
Volume 18, Issue 5 - May 2007
Volume 18, Issue 4 - Apr 2007
Volume 18, Issue 3 - Mar 2007
Volume 18, Issue 2 - Feb 2007
Volume 18, Issue 1 - Jan 2007
Selecting the target year
A New Cooperative Signal Transmission System Based on CDMA under Rayleigh Fading Channel
Choi, Jeong-Ho ; Kong, Hyung-Yun ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 4, 2007, Pages 351~357
DOI : 10.5515/KJKIEES.2007.18.4.351
In this paper, we propose a new cooperative signaling structure based on CDMA to overcome both 2/3 spectrum efficiency and low diversity gain of conventional cooperative signaling through continuous overlapping of signal that each user wants to transmit. Proposed signal structure can achieve the spectrum efficiency nearly "1" by receiving additional data for next time as well as maximum diversity gain to detect data continuously at both base station and each user. The orthogonality of CDMA's spreading codes can improve performance of optimal detector by reducing inter-user channel environment and distinguishing each user. We perform the computer simulation to verify the proposed system through comparing cooperative mode and non-cooperative mode under Rayleigh fading channel plus AWGN (Additive White Gaussian Noise).
Design of a Multi-Band and Wide-Band Antenna for a Portable Broadcasting Terminal
Kim, Jeong-Pyo ; Kim, Gi-Ho ; Yang, Myo-Guen ; Seong, Won-MO ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 4, 2007, Pages 358~363
DOI : 10.5515/KJKIEES.2007.18.4.358
The multi-band and wide-band antenna for a portable broadcasting terminal is proposed. The proposed antenna consists of two radiators with a parallel structure. The antenna has an enough wide impedance bandwidth for the DVB-H(Digital Video Broadcasting-Handheld) service band since two radiators have adjacent resonance frequencies and operates in the DAB(Digital Audio Broadcasting) service band using the third harmonic of the radiator 1. The fabricated antenna has VSWR characteristics of less than 2:1 in the frequency band
for DVB-H and
for DAB. The measured peak gain of the antenna is
in the DVB-H band and
in the DAB band.
Implementation of High-Power PM Diode Switch Modules and High-Speed Switch Driver Circuits for Wibro Base Stations
Kim, Dong-Wook ; Kim, Kyeong-Hak ; Kim, Bo-Bae ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 4, 2007, Pages 364~371
DOI : 10.5515/KJKIEES.2007.18.4.364
In this paper, the design and implementation of high-power PIN diode switch modules and high-speed switch driver circuits are presented for Wibro base stations. To prevent isolation degradation due to parasitic inductances of conventional packaged PIN diodes and to improve power handling capabilities of the switch modules, bare diode chips are used and carefully placed in a PCB layout, which makes bonding wire inductances to be absorbed in the impedance of a transmission line. The switch module is designed and implemented to have a maximum performance while using a minimum number of the diodes. It shows an insertion loss of
and isolation of 80 dB or more at 2.35 GHz. The switch driver circuit is also fabricated and measured to have a switching speed of
. The power handling capability test demonstrates that the module operates normally even under a digitally modulated 70 W RF signal stress.
Optimization and Improvements of Field Uniformity in a Reverberation Chamber with Schroeder Diffusers
Kim, Jung-Hoon ; Rhee, Joong-Geun ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 4, 2007, Pages 372~378
DOI : 10.5515/KJKIEES.2007.18.4.372
This paper presents an improvement of field uniformity in a reverberation chamber with QRDs(Quadratic Residue Diffuser) and also shows the optimal dimension of the QRDs. The QRD is designed for
frequency band and the FDTD(finite-Difference Time-Domain) method is used to analyze the field characteristics. At 2 GHz, the standard deviation of test volume in the reverberation chamber is the smallest when the QRD has
coverage of one side of the reverberation chamber and the field uniformity is worsened when the coverage of the QRD is either below 20 % or above 70 % of the area of the side wall. Particularly, the standard deviation of test volume in the reverberation chamber with 30 % coverage of QRD is improved by 1.53 dB compared to that of the reference chamber with no QRDs.
Real-Time Respiration and Heartbeat Detector Using a Compact 1.6 GHz Single-Channel Doppler Sensor
Lee, Hyun-Woo ; Park, Il-Ho ; Kim, Dong-Wook ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 4, 2007, Pages 379~388
DOI : 10.5515/KJKIEES.2007.18.4.379
This paper presents a real-time respiration and heartbeat detector comprised of a 1.6 GHz single-channel Doppler sensor and analog/digital signal processing block for remote vital sign detection. The RF front end of the Doppler sensor consists of an oscillator, mixer, low noise amplifier, branch-line hybrid and patch antenna. We apply artificial transmission lines(ATLs) to the branch-line hybrid, which leads to a size reduction of 40 % in the hybrid, while its performance is very comparable to that of a conventional hybrid. The analog signal conditioning block is implemented using second order Sallen-Key active filters and the digital signal processing block is realized with a LabVIEW program on a computer. The respiration and heartbeat detection is demonstrated at a distance of 50 cm using the developed system.
Design of Miniaturized Broadband Parasitic Patch Antenna Using Reduced Size Main Patch with U-Shaped Parasitic Patches
Wi, Sang-Hyuk ; Kim, Woo-Tae ; Hong, Young-Pyo ; Yuk, Jai-Rim ; Yook, Jong-Gwan ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 4, 2007, Pages 389~397
DOI : 10.5515/KJKIEES.2007.18.4.389
This paper proposes miniaturized broadband parasitic patch antenna. The proposed antenna consists of a probe fed reduced size main patch and U-shaped parasitic patches. The parasitic patches are incorporated to the radiating edges of the main patch to miniaturize the antenna size. The broadband impedance matching can be achieved by either E-plane or H-plane electromagnetic coupling between main patch and parasitic elements. The size of radiating elements is
and the overall dimension of designed antenna with substrate and ground plane is
. The fabricated antenna on a FR4 substrate shows two resonant frequencies(5.12 GHz and 6.08 GHz) with 27.3 %(1.5 GHz) fractional bandwidth at 5.5 GHz center frequency. The calculated and measured radiation patterns are almost similar to conventional patch antenna.
Design of a Tag Antenna with a Low Performance Distortion from an Attached Surface Material Using the Asymmetric Dual-Arm Dipole Structure
Kim, Do-Kyun ; Choo, Ho-Sung ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 4, 2007, Pages 398~407
DOI : 10.5515/KJKIEES.2007.18.4.398
In this paper we proposed the tag antenna with a low performance distortion from an attached surface material using the asymmetric dual-arm dipole antenna(ADDA) structure. The tag is designed to exhibit low performance changes when the tag is attached on a target object(the medical litter receptacle,
). Detail design parameters for the proposed antenna are optimized to maintain a good readable range in free-space as well as on a target object. The size of the optimized antenna is
. The antenna shows the matching bandwidth(
< -10 dB) of 3.7 % and the radiation efficiency of 80 % at the operating frequency. Finally we confirmed the readable range of the tag antenna by measurement and it shows about 5.3 m in free space and 5.5 m on the target object.
A Design of Ultra Wide Band Switched-Gain Controlled Low Noise Amplifier Using 0.18 um CMOS
Jeong, Moo-Il ; Lee, Chang-Seok ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 4, 2007, Pages 408~415
DOI : 10.5515/KJKIEES.2007.18.4.408
A switched-gain controlled LNA is designed and implemented in 0.18 um CMOS technology for
UWB system. In high gain mode, measurement shows a power gain of 12.5 dB, an input IP3 of 0 dBm, while consuming only 8.13 mA of current. In low gain mode, measurement shows a power gain of -8.7 dB, an input IP3 of 9.1 dBm, while consuming only 0 mA of current.
V/UHF-Band Broadband 2-Way Power Divider
Park, Yeo-Il ; Ko, Jin-Hyun ; Park, Young-Joo ; Park, Dong-Chul ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 4, 2007, Pages 416~422
DOI : 10.5515/KJKIEES.2007.18.4.416
In this paper, a broadband 2-way power divider which can be used from 20 MHz to 500 MHz in the V/UHF band is designed using transmission-line transformer and ferrite toroid. A 2:1 impedance transformer instead of the conventional 4:1 impedance transformer is realized and this 2:1 transformer is connected with the conventional bridge-type 2-way divider to form a 2-way power divider. Insertion loss of about 3.5 dB, isolation of less than -10 dB, and return loss of less than -10 dB in most band of interest are measured.
Design and Fabrication of Clock Recovery Module for Gap Filter of Satellite DMB
Hong, Soon-Young ; Shin, Yeoung-Seop ; Hong, Sung-Yong ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 4, 2007, Pages 423~429
DOI : 10.5515/KJKIEES.2007.18.4.423
The clock recovery module of gap filler for satellite DMB is proposed. Proposed module sustains the output frequency of 10 MHz whether the received signal from the satellite is unstable or cut off within 0.5 sec. The advantages of this module is without frequency tuning at regular interval and low material cost. This module is fabricated by using CPLD as clock recovery IC and new type of loop filter for satisfying the fast lock time and long hold over time simultaneously. The measured performance of the fabricated module has a holdover time of 11 sec at frequency stability less than 0.01 ppm, and phase noise of -113 dBc/Hz at 100 Hz offset.
Design of the Broadband TEM Horn Antenna Using a Genetic Algorithm
Na, Young-Sun ; Choo, Ho-Sung ; Lee, Joo-Gwang ; Kang, Jin-Seob ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 4, 2007, Pages 430~439
DOI : 10.5515/KJKIEES.2007.18.4.430
In this paper, we propose a broadband TEM horn antenna optimized using a genetic algorithm. The characteristics required for the TEM horn are the broad matching bandwidth from 2 GHz to 10 GHz and high gain in broadside with a small gain deviation within that bandwidth. In addition, a broadband balun is designed to improve the portability and to reduce the total size of the antenna. The measured return loss of the proposed TEM horn with the broadband balun is less than -10 dB(VSWR<2) from 2 GHz to 10 GHz. Compared to a conventional triangular type TEM horn, the proposed antenna shows about 80 % reduced volume and gives the broadside gain about 12 dBi with a gain deviation less than 6 dB from 2 GHz to 10 GHz. The time domain measurement shows less than 0.4 ns group delay and the pulse measurement using the transmitting signal with the rising time of 58.5 ps shows the received pulse with the rising time of 66.5 ps, which is less than 10 % rising time variation.
A Spread Spectrum System Using Adaptive Modulation and Switched Diversity
Park, Jin-Kyu ; Lim, Chang-Heon ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 4, 2007, Pages 440~447
DOI : 10.5515/KJKIEES.2007.18.4.440
The switched diversity, although its performance is a little inferior to the selection diversity, is widely used due to its advantage that only one RF circuit is required for its operation without respect to the number of antennas in use. In this paper, we propose an application of the antenna switched diversity to a spread spectrum system with adaptive modulation and derived the optimal antenna switching threshold to maximize the average transmission bit rate. We also compared the performances of the proposed system with those of the two cases using a single antenna and the selection diversity with two antennas in terms of the average number of bits per symbol(BPS), the probability of no transmission, and the average BER. The performance analysis shows that, if the number of paths in a multipath channel environment increases, the performance of the proposed scheme becomes closer to that of the selection diversity based system in terms of the average BPS. Furthermore, the proposed scheme produces as almost high the probability of no transmission as the selection diversity based system for the case of low average SNR, although the former yields a little higher probability of no transmission than the latter fer the case of high average SNR.
Game Theory for Transmission Power Control of Cognitive Radio
Hwang, In-Kwan ; Lee, Ryoung-Kyoung ; Cho, Hae-Keun ; Lim, Yeon-Jun ; Ko, Eun-Kyoung ; Song, Myoung-Sun ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 4, 2007, Pages 448~454
DOI : 10.5515/KJKIEES.2007.18.4.448
In this paper, the game theory based power control for CDMA system is studied, which has attained intensive interest as a core artificial intelligent technology fur cognitive Radio and its efficiency is evaluated using performance metrics such as system throughput and fairness. Utility Function for joint user centric and network centric power control is defined and simulation results show that game theory based power control is far better than closed loop power control. The contribution of this raper is to formalize the game theory based power control toward the cognitive radio that recognizes and adapts to the radio communication environments.
Near-Range Object Detection System Based on Code Correlation
Yoo, Ho-Sang ; Gimm, Youn-Myoung ; Jung, Jong-Chul ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 18, issue 4, 2007, Pages 455~463
DOI : 10.5515/KJKIEES.2007.18.4.455
In this paper, it is proposed how to implement the object detection system which is able to apply to vehicular applications, unmanned facilities, automatic door and others with microwave. As the technology which detects an object with microwave is becoming more popular, it seems impossible to avoid mutual interference and jamming caused by limited frequency bandwidth. The system in this paper detects an object by correlating the code of TX and RX signals with the pseudo-random code having best quality in interference and jamming environment. In order to generate simulant doppler signal for detecting the distance of an fixed object where there is no doppler effect, the phase of TX signal is shifted continually. Also, the saturation of receiver was removed and the error of distance measurement was decreased by controlling the power of TX signal for getting constant RX signal. The proposed system detects a object which ranges from 0.5 m to 2.0 m and informs vocally whether there is the object within 1.0 m or not.