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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 13, Issue 10 - Dec 2002
Volume 13, Issue 9 - Oct 2002
Volume 13, Issue 8 - Sep 2002
Volume 13, Issue 7 - Aug 2002
Volume 13, Issue 6 - Jul 2002
Volume 13, Issue 5 - Jun 2002
Volume 13, Issue 4 - Apr 2002
Volume 13, Issue 3 - Mar 2002
Volume 13, Issue 2 - Feb 2002
Volume 13, Issue 1 - Jan 2002
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Two-Ann Microstrip Spiral Antenna with a Circular Aperture on the Ground Plane for Generating a Circularly Polarized Conical Beam
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 9, 2002, Pages 851~857
A two-arm microstrip spiral antenna with a circular aperture on the ground plane that generates a circularly polarized conical beam is presented in this paper. We obtained circularly polarized conical beam by using two spirals that are excited in-phase from the microstrip feed lines. The main beam directions of the conical beam from the broadside are approximately 40
in the range from 5 GHz to 6.5 GHz, and 58
from 9 GHz to 11 GHz. Since the proposed antenna has omni-directional conical beam pattern, it is suitable for use in mobile communication systems.
Performance Analysis of Ultra Wideband Impulse Radio System in Partial Band Interference Environment
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 9, 2002, Pages 858~864
In this paper, Analyzed Performance of TH/UWB(Time Hopping/Ultra Wideband after Impulse Radio) system in interference environment by existing system that use same frequency band. In case interference fraction ratio is below 0.1, consider and analyzed in case influence through interference in IR system that is shared in 3.1 - 10.6 GHz band hereafter as case that use very small and narrow band than IR system such as 80 MHz bandwidth of ISM band or 802.1la's use bandwidth 20 MHz in 5 GHz band. According to result, we could know that Performance change according to possession band width of interference shows greatly than size of interference electric power. Also, interference fraction ratio is big (more than 0.1) narrowband interference in partial band interference environment, could get Performance improvement of big width increasing pulse repetition number. But, could know that do not influence hardly in system performance when interference fraction ratio is small (below 0.1) narrowband interference. Therefore, may receive the best system performance and transfer efficiency by set the most suitable pulse repetition number according to bandwidth fraction ratio of interference through correct interference fraction ratio estimation and apply proper interference suppression techniques.
Beam Steering Antenna using Rotman Lens for BMWS Application
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 9, 2002, Pages 865~872
The conventional Rotman lens antenna using a waveguide lens has the bended waveguide from the inner lens contour to the antenna element. However in this paper the improved Rotman lens antenna having a straight waveguide is proposed. By applying this technique, the beam steering antenna for BMWS application which has 3 input ports and 6 antenna elements consisted of open-ended waveguide has been designed and fabricated. From the measurement, the gain of the beam steering antenna is 15.4 ~ 17.2 dB. The direction angle is 0
and the side lobe level is -l0 ~ 20 dB.
Design of Dipole Array Antennas for PCS/IMT-2000
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 9, 2002, Pages 873~881
In this paper, the rectangular reflector antenna with 8-dipole array for PCS band (1,750 MHz ~ l,870 MHz) and IMT-2000 band(1,885 MHz ~ 2,200 MHz) is designed and the radiation characteristics are analyzed using the method of moments and HFSS(High Frequency Structure Simulator). To verify the analysis results, rectangular reflector antenna with 8-dipole array is fabricated and the calculated results are compared with the measured results. The measured results show good agreement with the calculated results. As a result of measurements, bandwidth(VSWR< 1.5) of 450 MHz is achieved at PCS and IMT-2000 band and gain is 16 dBi. The designed antenna can be used as the base station antenna for PCS/IMT-2000.
A Newly Proposed Bias Stability Circuit for MMIC율s Yield Improvement
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 9, 2002, Pages 882~888
This paper proposed a bias stability circuit that compensates the degradation of MMIC's performance for the variation of the process and temperature. The proposed bias circuit proved the superior effect compared with the conventional bias circuit using the constant current source. It designed and fabricated simultaneously two amplifier on one layout for comparison in same conditions. One is amplifier with conventional bias circuit using constant current source and the other is amplifier with proposed bias stability circuit. The chip was measured the microwave performances under process variation that classed the level NOM, MIN and MAX. The amplifier with a conventional bias circuit using constant current source has 6.4 dB gain variation and 7 mA Ids variation at 1.8 GHz, but the amplifier with the proposed bias circuit has the 2.1 dB gain variation and 3 mA Ids variation. As the result, MMIC having the proposed bias circuit shows the superior compensation of the quiescent point than the MMIC having the conventional bias circuit under the variations of the process and temperature and can improve the yield of the MMIC. The fabricated chip size is 1.2 mm
Performance Evaluation of an Improved Block Coding for PAPR Reduction
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 9, 2002, Pages 889~897
In this paper, we propose an improved block coding scheme for PAPR reduction in the OFDM communication system. Unlike the conventional block coding scheme which uses one block encoder of subcarrier N, two block encoders of subcarrier N/2 is used for the proposed block coding scheme. This not only improves the coding gain, but enhances the spectral efficiency by twice due to the increment of code rate. PAPR Reduction performance is the same as the conventional block coding. When BER is
, the proposed block coding scheme has coding gain of 0.5 dB than the conventional scheme.
Analysis of the Influence of Mutual Relation of Optical Pulse Frequency Chirp and Kerr Effect on the Mid-Span Spectral Inversion Methods for the Long-Haul Optical Transmission
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 9, 2002, Pages 898~906
In this paper, we investigated the improvement degree of transmission distance of the various initial frequency chirped optical pulse with 5 dBm initial power dependence on the various bit rate and fiber dispersion coefficient, when MSSI(Mid-Span Spectral Inversion) with the optimal pump power condition is adopted for the compensation method for optical pulse distortion. And we analyzed the influence of mutual relation of optical pulse frequency chirp and Kerr effect on the MSSI methods for the long-haul optical transmission through the computer simulation. We found that the compensation degree of distorted optical pulse varies as a consequence of the variation of combined phase modulation of self phase modulation(Kerr effect) and initial frequency chirp parameter dependence on the fiber dispersion coefficient. And we found that, if the transmission bit rate is increased k times, the dispersion coefficient value of dispersion shift fiber is decreased
times so as to be almost the same performance of the transmission system with k times lower bit rate.
X-band Compact Digital Phase Shifter Design
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 9, 2002, Pages 907~915
In this paper, a compact digital phase shifter to be used an active phased array antenna system for satellite communications was proposed. The even and odd mode analysis for a given reflection-type phase shifter, which uses a folded hybrid coupler as a base element, was performed and the design parameters were derived. Also, to verify experimentally the electrical performances of the proposed structure, X-band 4-bit digital phase shifter was designed and fabricated using Teflon soft substrate
. Its circuit size was less than 3.5 cm
3.0 cm, and it exhibited at least 50 % size reduction as compared with the conventional unfolded configuration. The experimental results of the fabricated phase shifter showed that the average insertion loss and insertion loss variation were less than 3.5 dB,
0.6 dB within the operating band, 7.9 ~ 8.4 GHz, respectively. And, input and output return loss were more than 10 dB, respectively. Also, the phase response of the phase shifter showed 4-bit operation with
rms phase error.
ITS/DSRC Frequency Reuse Method using XPIC
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 9, 2002, Pages 916~923
In this paper, we propose dual-polarization technique which double the system capacity without increasing any other bandwidth. In theory, dual-polarization technique can double system capacity by using an orthogonal electromagnetic wave. However, cross-polarization interference and multipath interference degrade system performance in practice. To cope with this problem, we propose Cross Polarization Interference Canceller(XPIC) for ITS/DSRC system which can mitigate the XPI as well as multipath propagation interference. We also analyze and discuss its performance with relevant computer simulation results.
Power Amplifier Design using λ/4 DGS(Defected Ground Structure) Bias Line
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 9, 2002, Pages 924~931
In this paper, a new λ/4 bias transmission line that is added dumbbell-shaped defected ground structure(DGS) on ground plane of the conventional λ/4 bias transmission line is proposed. This DGS λ/4 bias transmission line maintains high characteristic impedance, but physical width is wider and length is shorter than that of the conventional bias line. If the proposed bias line is attached on signal transmission line, this bias line can reduces the
harmonic signal as well as the
harmonic signal. With harmonic reduction characteristics, efficiency and linearity of amplifier are improved. The proposed bias line is adopted in power amplifier on IMT-2000 base-station transmitting band. This paper presents several simulations and experimental results of DGS to show validity of the proposed power amplifier using the new λ/4 bias transmission line. Experimental results represent that the
harmonic signal is reduced about 26.5 dB and efficiency is improved about 9.1 % and IMD3 is improved 4.5 dB than the conventional structure.
Use of Dummy Antenna to Monopole Antenna Factor
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 9, 2002, Pages 932~936
This paper has been studied a calibration techniques in CISPR A for 1 m monopole antenna factor in the frequency range below 30 MHz. The equivalent capacitance substitution method uses a dummy antenna in place of the actual rod element. Dummy antenna measure frequency from 150 kHz to 30 MHz and good results factor from 150 kHz to 25 MHz compare to using 1 m monopole antenna factor. It will be use to substitute dummy antenna factor for 1 m monopole antenna factor.
Analysis of Transient Scattering from Conducting Objects using Weighted Laguerre Polynomials and Electric Field Integral Equation
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 9, 2002, Pages 937~946
In this paper, we present a stable solution of the transient electromagnetic scattering from the conducting objects. This method does not utilize the conventional marching-on in time (MOT) solution. Instead we solve the time domain integral equation by expressing the transient behavior of the induced current in terms of weighted Laguerre polynomials. By using this basis functions for the temporal variation, the time derivative in the integral equation can be handled analytically. Since these temporal basis functions converge to zero as time progresses, the transient response of the induced current does not have a late time oscillation. To show the validity of the proposed method, we solve a time domain electric feld integral equation and compare the results of MOT, Mie solution, and the inverse discrete Fourier transform (IDFT) of the solution obtained in the frequency domain.
Capacity and Coverage according to Calculations of the Erlang Capacity in the Reverse Link of a DS/CDMA System
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 9, 2002, Pages 947~955
In this paper, we derive an outage probability for the Erlang capacity and the link margin respectively, calculate them with the same parameters and outage probability, and then analyze a capacity and cell coverage in city, suburban, and open area. So, the Erlang capacity is more real than in a cell, and the cell coverage can be calculated with high reliability by the margin. When the
decreases from 7 dB to 5 dB within the outage probability of 5 %, it is observed that the capacity is increased from 18 Erlang to 31 Erlang with the same margin of 2.8 dB, then the coverage is increased to 0.4 km, 1 km, and 2.5 km in city, suburban, and open area respectively. Also if the outage probability is decreased from 5 % to 2 % in case of
of 5 dB, the result shows a very reliable link with additional increment of 0.88 dB in the margin and a high QoS (quality of service) within decrement of 0.15 km, 0.5 km, and 1.5 km for the same areas with decrement of 3 Erlang from 31 Erlang.
Slit Folded Type Microstrip Antenna for Omnidirectional E-plane and H-plane
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 9, 2002, Pages 956~963
A linearly polarized folded type and H-shape slit folded type microstrip patch antenna at GPS(center frequency:1.575 GHz) were designed and fabricated by folding a conventional single
rectangular patch a half along the length direction at the center of patch and inserting ground plane in the middle. As a result, two types of omnidirectional radiation patterns for E-plane (for zx-plane) in the direction of the length of patch and H-plane (for xy-plane) have been acquired. The experimental results show that the average gains of folded type and slit folded type for omnidirectional E-plane and H-plane are -1.5 dBd (-2.4 dBd) and -3.27 dBd(-2.5 dBd). Slit folded type microstrip patch antenna was more miniaturized than folded type microstrip patch antenna by 27.5 %. In case of slit folded type antenna, average gains of omnidirectional radiation pattern for E & H-plane are almost same.
Base Station Antenna of Radiation Pattern for the Cruciform using Monopole Array
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 9, 2002, Pages 964~970
In this paper, cruciform radiation pattern antenna was designed and fabricated. The fabricated antenna is applicable to intersections which is composed of four eight-lane roads each having 60 m of width and 200 m of length. The design theory was based on Woodward-Lawson method and the 6 monopole elements with the strip feeding network are made by linear array on the micro-strip board. In the results, - 13.5 dB of return loss and 120 MHz(6 %) of -10 dB bandwidth were obtained at the 2 GHz. Also, at 1.95 GHz, -6 dB of gain fall was seen at
and thus, it is possible to say that the presented antenna has well-shaped cruciform radiation pattern.