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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 17, Issue 12 - Dec 2006
Volume 17, Issue 11 - Nov 2006
Volume 17, Issue 10 - Oct 2006
Volume 17, Issue 9 - Sep 2006
Volume 17, Issue 8 - Aug 2006
Volume 17, Issue 7 - Jul 2006
Volume 17, Issue 6 - Jun 2006
Volume 17, Issue 5 - May 2006
Volume 17, Issue 4 - Apr 2006
Volume 17, Issue 3 - Mar 2006
Volume 17, Issue 2 - Feb 2006
Volume 17, Issue 1 - Jan 2006
Selecting the target year
Design and Implementation of 2.4/5 GHz Dual-Band Plate Type Antenna for Access Point of Wireless LAN
Lee Won-Kew ; Son Ji-Myoung ; Han Jun-Hee ; Yang Woon-Geun ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 17, issue 5, 2006, Pages 401~407
In this paper, we present a small-sized and light weighted dual-band antenna for an access point of 2.4/5 GHz dual-band WLAN(Wireless Local Area Network). The antenna for WLAN should show the characteristic of omni-directional radiation pattern. First, to obtain the omni-directional radiation pattern the proposed dual-band antenna has an orthogonal inverted triangular type element at the center and locates four resonating elements symmetrically around it. Also, for the purpose of easy manufacturing and miniaturization of the antenna, we changed the central element which had the orthogonal inverted triangular type structure into the plate type. Measured
for the proposed dual-band plate type antenna showed characteristic which was less then -12.8 dB for WLAN frequency bands. Measured results for the maximum gain showed 3.17 dBi at 2.44 GHz, 5.38 dBi at 5.77 GHz with omni-directional radiation pattern. The implemented antennas showed applicable performances for the access point of WLAN.
Modeling of Memory Effects in Power Amplifiers Using Advanced Three-Box Model with Memory Polynomial
Ku Hyun-Chul ; Lee Kang-Yoon ; Hur Jeong ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 17, issue 5, 2006, Pages 408~415
This paper suggests an improved system-level model of RF power amplifiers(PAs) including memory effects, and validates the suggested model by analyzing the power spectral density of the output signal with a predistortion linearizer. The original three-box(Wiener-Hammerstein) model uses input and output filters to capture RF frequency response of PAs. The adjacent spectral regrowth that occurs in three-box model can be perfectly removed by Hammerstein structure predistorter. However, the predistorter based on Hammerstein structure achieves limited performance in real PA applications due to other memory effects except RF frequency response. The spectrum of the output signal can be predicted accurately using the suggested model that changes a memoryless block in a three-box model with a memory polynomial. The proposed model accurately predicts the output spectrum density of PA with Hammerstein structure predistorter with less than 2 dB errors over
MHz adjacent channel ranges for IEEE 802.11 g WLAN signal.
Design of Wideband Antenna for IEEE 802.11a
Ju Seong-Nam ; Kim Pyoung-Gug ; Kim Kab-Ki ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 17, issue 5, 2006, Pages 416~422
In this paper, we have designed and favricated the high gain and wideband microstrip patch antenna including IEEE 802.11a. To widen the bandwidth of microstrip antenna, firstly we have used the microstrip line-coaxial probe feeding method and inserted a U-slot in the rectangular patch. Secondly, to improve the antenna gain, we have used a
array structure. From the measured results, wideband characteristics of 1 GHz bandwidth(
GHz) for VSWR<2 was obtained. The measured eain was 13 dBi in both the E-plane and H-plane at the frequency of 5.15 GHz, 5.35 GHz, 5.50 GHz, and 5.85 GHz.
A Study on Development of Electro Magnetic Wave Absorbers for Mobile Phones
Choi Yun-Seok ; Jung Jae-Hyun ; Kim Dong-Il ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 17, issue 5, 2006, Pages 423~429
This paper deals with research for development of electromagnetic wave absorbers in sheet type for mobile phones. By controlling the sendust ratio, the
coating, the thickness, the kind of binders, and the milling time, electromagnetic wave absorbers were prepared and examined. Central frequency shills toward lower 2.2 GHz, 1.29 GHz, 842 MHz with increasing thickness 1 mm, 2 mm, 3 mm of the absorber, and absorption ability controlled each 2.2 GHz to 1.91 GHz, 1.29 GHz to 801 MHz, 842 MH2 to 801 MHz adjust sendust amount from 80 wt% to 85 wt%. The absorption band of the electromagnetic wave absorber coated with
becomes larger than that of non-coated one. Sendust composite microwave absorbers mixed with CPE were prepared at
in temperature. The fabricated electromagnetic wave absorbers show a reflection coefficient 5.76 dB at 1.8 GHz in thickness of 0.85 mm.
Wave Propagation Characteristics for Mobile Communications beyond 3G in Microcellular Environments
Jo Han-Shin ; Yook Jong-Gwan ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 17, issue 5, 2006, Pages 430~439
This paper presents the a measured path-loss characteristics for mobile communications beyond 3G in microcellular residential area and street microcell at 3.4, 5.3, and 6.4 GHz band signals. The residential area is divided into two sections, one of which is composed of fifteen-story appartment buildings. The other section comprises four-story houses. The street microcell is classified line-of-sight(LOS) and nonline-of-sight(NLOS) areas. Both residential areas have standard deviations independent of the residential area classification, whereas the path loss exponents in the apartments is higher than those in area for same frequencies. A two-ray model is applied to analyse the path-loss charateristics in LOS areas. In LOS areas, an empirical breakpoint, whose distance is 6 percent shorter than a theorical breakpoint, is founded. Further, a sudden power level drop occurs at a transition point from LOS region to NLOS area. Path loss exponent is found to be significantly higher for non-LOS region than for LOS region. The power level drop due to corner loss and path-loss exponents both increase as the distance between the transmitter and the corner increases.
Frequency Sharing of TDD-OFDM/OFDMA Based Systems beyond 3G with Fixed Satellite Service Earth Station
Jo Han-Shin ; Yoon Hyun-Goo ; Yook Jong-Gwan ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 17, issue 5, 2006, Pages 440~450
In this paper, the frequency sharing issue between time division duplex-orthogonal frequency division multiplexing/orthogonal frequency division multiple access(TDD-OFDM/OFDMA) based systems beyond third generation(B3G) and fixed Satellite Service(FSS) earth station has been studied. The conventional advanced minimum coupling loss(A-MCL) is adopted to assess the interference from a single base station(BS) of B3G systems. The aggregated interferences from base stations and mobile stations(MS) are evaluated by applying the extended A-MCL and analysed with a cumulative density function(CDF). The minimum distances that enable a single FSS earth station to sharing the frequency with a single BS are between 4 and 53.3 km. In the case of 20 MS per sector, the BS-to-BS distance and the minimum distance between a ES and BS are 6.5 and 2.8 km, respectively.
Development of Local-Exposure Systems for In Vivo Studies at Mobile-Phone Frequency Bands
Ko Chea-Ok ; Park Min-Young ; Doh Hyeon-Jeong ; Kim Jeong-Lan ; Jung Ki-Bum ; Pack Jeong-Ki ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 17, issue 5, 2006, Pages 451~460
We have designed local exposure systems for long-time mice experiments in PCS and cellular frequency band(PCS: 1,762.5 MHz, cellular: 848.5 MHz). The fabricated systems are local exposure systems of carousel type, and 40 mice can be exposed at a time. In order not to give extra stress to the mice ender experiment, the systems were fabricated to meet the environmental conditions such as illumination, ventilation, noise etc. SAR measurement was performed using a temperature probe. Measurements at 3 points in the head of mouse cadaver and solid phantom were made, and it has been confirmed that the measurement results are in good agreement with the simulation results in the real exposure environment. The exposure systems are currently used for long-term mice experiments.
A Study on Mobile Antenna System Design with Tri-band Operation for Broadband Satellite Communications and DBS Reception
Eom Soon-Young ; Jung Young-Bae ; Son Seong-Ho ; Yun Jae-Seung ; Jeon Soon-Ick ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 17, issue 5, 2006, Pages 461~475
In this paper, it is described about the tri-band mobile antenna system design to provide broadband multimedia and direct broadcasting services using goo-stationary Koreasat 3, simultaneously operated in Ka/K/Ku band. The radiating part of the antenna system with a fan beam characteristic in the elevation plane is composed of the quasi-offset dual shaped reflector and the tri-band feeder. The tri-band feeder is also composed of the Ka/K dual band feeder with the protruding dielectric rod, the circular polarizer, the ortho-mode transducer and the circular-polarized Ku band feed array. Especially, the Ka/K dual band circular polarizer was realized firstly using the comb-type structure. For fast satellite-tracking on the movement, the Ku band feed array has the structure of the
active phased array which can make electrical beams. And, the circular-polarized characteristic in the feed array was improved by
rotating arrangement of four radiating elements polarized circularly by a
hybrid coupler, respectively. Four beam forming channels to make electrical beams at Ku band are divided into the main beam channel and the tracking beam channel in the output, and noise temperature characteristics of each channel were analyzed on the basis of the contributions of internal sub_units. From the fabricated antenna system, the output power at
of Ka_Tx channel was measured more than 34.1 dBm and the measured noise figures of K/Ku_Rx channels were less than 2.4 dB and 1.5 dB, respectively, over the operating band. The radiation patterns with co- and cross-polarization in the tri-band were measured using a near-field measurement in the anechoic chamber. Especially, Ku radiation patterns were measured after correcting each initial phase of active channels with partial radiation patterns obtained from the independent excitation of each channel. The antenna gains measured in Ka/K/Ku band of the antenna system were more than 39.6 dBi, 37.5 dBi, 29.6 dBi, respectively. And, the antenna system showed good system performances such as Ka_Tx EIRP more than 43.7 dBW and K/Ku_Rx G/T more than 13.2 dB/K and 7.12 dB/K, respectively.
A Study on Design of Multimode Feed Horn Antenna for High Power Microwave Antenna System
Lee Sang-Heun ; Yoon Young-Joong ; Lee Byoung-Moo ; So Joon-Ho ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 17, issue 5, 2006, Pages 476~482
In this paper, a multimode feed horn antenna is suggested for a high power microwave(HPM) antenna system. The proposed HPM feed horn antenna which is connected with a mode converter is located between source and reflector antenna. A multimode feed horn antenna which has reduced -25 dB beamwidth is designed and fabricated for miniaturization of reflector antenna because -25 dB beamwidth which is determined by considering spillover of feed horn antenna decides a size of reflector in case of HPM. As a result, feed system which uses the multimode feed horn antenna has high gain about 27 dBi and return loss is less than -22 dB at 10 GHz. The measured -25 dB beamwidths of the radiation pattern at vertical, horizontal-plane equal to
which is less than about
beamwidth of conventional feed system. Thus the suggested feed hem antenna is suitable to feed horn for miniaturization of HPM antenna system.
A Study on the Lens Amplifier for Wideband Spatial Power Combining
Kwon Oh-Sun ; Kwon Se-Woong ; Lee Byoung-Moo ; Yoon Young-Joong ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 17, issue 5, 2006, Pages 483~489
In this paper, new wideband lens amplifiers are proposed for C-band wireless communication service. In order to obtain the wideband property, all components of the proposed lens amplifiers are designed with balanced structure and wideband characteristics. Fat dipole antenna as the input and output antenna, balanced amplifier as amplifying components, and coplanar stripline(CPS) as the delay line fer the beam focusing are used fur composing the stable wideband lens amplifier. The
2D lens amplifier has the characteristics that the absolute gain is 7.5 dB, the EIPG is 37.4 dB at 6 GHz, and the 3-dB gain bandwidth is 19.8 %.
Measurement of UHF-Band Propagation Loss for the Long Range Maritime Communication Environment
Kim Kyun-Hoi ; Tak Youn-Do ; Shin Seok-Hyun ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 17, issue 5, 2006, Pages 490~499
In this paper, we present the newly developed propagation toss model of a long range maritime communication channel, measured by a ground to air flight test, and discuss its validity compared with the predictive value based on the spherical earth reflection model. To measure the propagation loss, actual flight test was performed in the Yellow Sea and the measurement of receiving signal strength was made for overall test range. As far as the test condition is concerned, it is expected that the receiving signal strength must be interfered with the reflected wave by an island existing around the reflection point. Therefore we introduce some modifications on the conventional spherical earth reflection model by including the effect due to the reflected wave from the island. And then, we compare the path loss measured by flight test with that one analyzed by the spherical earth reflection model accounting for reflected wave of the island. As a result of the comparison, it is verified to predict the path loss accurately by the spherical earth reflection model including the effect due to the reflected wave from an island for a long range ground to air communication.