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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 12, Issue 7 - Dec 2001
Volume 12, Issue 6 - Oct 2001
Volume 12, Issue 5 - Aug 2001
Volume 12, Issue 4 - Jun 2001
Volume 12, Issue 3 - Apr 2001
Volume 12, Issue 2 - Feb 2001
Volume 12, Issue 1 - Jan 2001
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A Study on the Small Isolator Characteristics and Design of Mobile Phones
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 2, 2001, Pages 165~175
In this paper, it is analyzed lumped element isolators analytically by the analysis program using scattering matrixes including ferrite saturation magnetization, external direct current magnetic field and strip line length and width, designed and experimented the small isolator of mobile phone. The simulation results show that the characteristics of the isolator are affected by external R, C, length and width of strip line and ferrite width and saturation magnetization sensitivity. We proposed the isolator specification applied cellular and PCS mobile phones, experimented the isolator for cellular mobile phones. From the experimented result, isolation and return loss are measured below 20 dB, insertion loss is below 0.7 dB, bandwidth is about 44 MHz at center frequency 836.5 KHz. The implemented isolator has better performances than the conventional one.
Development of a Cavity Stabilized Gunn Oscillator at 24 GHz
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 2, 2001, Pages 176~183
A cavity stabilized Gunn oscillator at 24 GHz has been developed with WR-42 waveguide structure by HFSS simulation. The oscillator has been optimized by using a circular iris and cap resonator structure. This oscillator needs 4.5 V DC voltage / 1.2 A current and produces a maximum +21.27 dBm RF power at 24.0675 GHz.
A Analysis on the Result of CE/CS Test on the KOMPSAT-I ETB
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 2, 2001, Pages 184~192
In this paper, we analyze the result of the conduced emission and susceptibility tests performed on the KOMPSAT-I ETB Platform. The ETB platform consists of the EM (Engineering Model) boxes developed to perform the electrical functional test. During the conducted emission test, we measured the instant waveform in time domain when each switch was turn on, and spectrum of the noise in the frequency range of 10 Hz up to100 MHz fur the steady state of the ETB. During the conducted susceptibility test, no malfunction and no serious damage of the electronic box were observed when a simulated noise waveform was applied to the DC power bus. The simulated waveform was obtained by adding the 6 dB-system margin to the worst case waveform measured from the conducted emission. This test was performed as co-development of the KOMPSAT-I with TRW in USA.
Polarization-independent Bragg blazing and Simultaneous Bragg and off-Bragg Blazing in a Periodic Strip Grating Structure over a Grounded Dielectric Slab
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 2, 2001, Pages 193~198
The Prediction and Analysis of the Propagation Characteristics in Indoor Environments Using the SBR/Image Method
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 2, 2001, Pages 199~207
In this paper, the technique of prediction and analysis on the characteristics of propagation in indoor environment is presented. This technique needs no reception sphere commonly used in 3D-ray tracing scheme, and thereby it lends us easy code realization. The validity of developed code is verified by comparing with the values of image methods and measurement. The developed technique applied to the structure of rectangular corridor with the iron door and we calculated the path loss for the variation of the iron door angle. The path loss decreased about 15 dB at the distance of30 m from the iron door and the delay spread increased approximately by four times. Based on the computation, we confirmed that indoor propagation in PCS is heavily affected by the iron door in corridor.
Performance Analysis of Noncoherent Transmit Diversity System over Correlated Rayleigh Fading Channel
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 2, 2001, Pages 208~216
Signal Fading due to multipath propagation severely impairs the performance of high-speed mobile communication systems. Effective diversity scheme for fading channel is STTD (Space Time Transmitter Diversity) method. This scheme is very simple and using 2 transmit antennas and 1 receive antenna provides a diversity order of two,. In this paper, we derive the new probability density function of the envelope of the received signal over correlated Rayleigh fading channel. Using the new pdf of the envelope we analyze the performance of noncoherent M-ary FSK, DPSK and ASKSTTD (Space Time Transmitter Diversity) a system on correlated Rayleigh fading channel.
Small-Sized GPS/GLONASS Patch Antenna Using a Ceramic Dielectric
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 2, 2001, Pages 217~226
A small sized ceramic dielectric patch antenna is designed and implemented for GPS/GLONASS combined receiver, and it shows a wideband characteristics with circular polarization. For the miniaturization of the antenna, high-permittivity dielectric material is used, and the wideband characteristics with low axial-ratio is achieved by using dual feed with 90
phase difference. The measured data of the manufactured antenna show that the bandwidth is 242 MHz, the axial ratio is less than 3 dB, the half-power beam-width is more than 112
, and the antenna satisfies the required characteristics of the GPS/GLONASS antenna.
Field Distribution Characteristics of A Reverberation Chamber with Different Conditions of Diffuser Arrangement
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 2, 2001, Pages 227~233
Electromagnetic field characteristics of Reverberation chamber, which could be applicable for an alternative test facility of electromagnetic interference and radiated electromagnetic susceptibility have been investigated. To obtain the required field uniformity of reverberation chamber, Schroeder method Quadratic Residue Diffuser was designed to be applied to chamber. In this paper, 3 different types of diffusers depending on diffuser's periodic direction have been used to investigate field characteristics of each type by using FDTD numerical method. The results show all 3 types of reverberation chambers have below
3 dB tolerance of field uniformity characteristics, and the symmetrical, type 3, structure show better results among them.
Development of Frequency Aliasing Resolution of SAR Data by Using Wrap Around Removal Technique
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 2, 2001, Pages 234~244
A Study on Development of EMC Filter for Power Lime in Break-box
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 2, 2001, Pages 245~250
Since the most of malfunctions in the industrial equipment controlled by processors is occurred by the Electrical Fast Transient(EFT), the International Electrotechnical Commission(IEC) prepared the dummy signal to test the immunity level of the equipments. In this paper, we designed a new EMC fitter for power line in break-box, which consist of the feed-through capacitor and ferrite materials with high permeability, which was wound or inserted, in the second layer of the power cable in order to increase common mode inductance. We have obtained a excellent insertion loss characteristics over wide frequency band from 10 MHz up to 1.5 GHz. It is expected that the new EMC filter could be effectively used for industrial, MIL, and medical equipments to reduce a malfunctions and be suitable for IEC 61000-4-4
Effects of Partial-band Noise Interference on the Performance of Hybrid Ds/SFH-MSK Spectrum System in Rayleigh Fading Channel
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 2, 2001, Pages 251~256
An error probability analysis is performed far a hybrid DS/SFH spread-spectrum system using minimum shift keying(MSK) modulation. The channel is assumed to be a Rayleigh fading channel with partial-band noise interference. Expressions are derived for the bit error rate(BER) in the context of Rician and Rayleigh fading channels, as a function of the average signal-to-noise ratio(SNR)
, the average signal-to- interference ratio(SJR)
, and channel parameters. As a result, in the fading channel with large Rician factor, K, which denotes the ratio of power of the direct and the diffused components, the partial-band interference is the worst case. On the other hand, in Rayleigh fading channel(K=0), the full-band interference(
=1) brings the system to the worst case. Performance comparisons among various channels show that the factor K has much large effect on overall performance. For example, in conditions of
=0.1 and BER=
, the system in Rician channel with K=10 requires more 1.9 dB SNR than that in AWGN channel, whereas it is less 5 dB SNR than that in the Rayleigh channel with K=0
Design for a Single-layer Feeder Waveguide Array using
-Junctions with the Inductive Wall
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 2, 2001, Pages 257~267
This paper presents a design for a single-layer feeder waveguide array using
-junctions with the inductive wall. The feed structure consists of a single waveguide placed on the same layer as radiating waveguide and is characterized by the unit divider, called a
-junction with an inductive wall splits part of the power into two branchs waveguide through one coupling window, and can excite densely arrayed waveguide at equal phase and amplitude. The power dividing characteristics of the cascade of
-junctions are analyzed by Galerkin's method of moments. The numerical results show reasonable agreement with the experimental results. From the optimum simulation results based on the feeder waveguide using
-junction, we obtained the scattering matrices of the feeder divided power at 3.95 GHz.
Performance Analysis of a OFDM System for Wireless LAN in Indoor Wireless Channel
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 2, 2001, Pages 268~277
In this paper, the system performance with the convolution code using a Viterbi decoding and the one tap LMS equalizer applied to the OFDM system, which is suitable for IEEE 802.1la wireless LAN in indoor wireless channel, is analyzed through computer simulation. Indoor wireless channel is modeled as Rician fading channel, and QPSK and 16QAM scheme are used for subchannel modulation. In Rician fading channel with the power ratio of the direct path signal to the scattered signals, K=5 dB, BER of
is satisfied if the SNRs of the QPSK/OFDM and the 16QAM/OFDM are 8.6 dB and 19.2 dB in hard decision and 5.3 dB and 9.8 dB in soft decision, respectively. Compared with convolution code scheme, it is observed that 16QAM/OFDM system with the one tap LMS equalizer has the performance improvement of 8.6 dB and 2 dB in hard decision and soft decision, respectively.
A FDTD Analysis for the Slanted Metallic Boundaries
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 2, 2001, Pages 278~284
In this paper, the slanted metallic boundaries is analyzed for the triangular cell grid method and compared with staircase approximation. Specially, this paper is derived an error range to the angle of inclination between the metal and the dielectric from the triangular cell grid method. That result, when the angle of inclination is from 30˚ to 60˚, the triangular cell grid method improves the accuracy, the computer memory and time requirement in comparison with the staircase approximation. But, out of this range, we do not expect the accuracy because a side of cell size lengthen.
Rerformance Analysis of 16 QAM System in a Composite Electromagnetic Interference Environment
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 2, 2001, Pages 285~292
In this paper, the analysis model of a composite electromagnetic interference environment is proposed, and the composite interference consists of three types, i.e., impulse, sinusoidal, and rectangular type. Also, we have derived the p.d.f of the amplitude of the composite interference. And using a derived p.d.f, we have evaluated the performance of 16QAM (Quadrature Amplitude Modulation) system in a composite electromagnetic interference environment. From the results, it is known that when impulse type interference is weaker than the others, the shape of p.d.f is dominantly governed by the power component ratio of sinusoidal and rectangular type interference. On the other hand, when impulse type interference is stronger, the effect of the other two interference becomes insignificant. Also, It is shown that the smaller both impulsive index (A) and the mean power component ratio (
') in impulse type interference are, the worse the performance of 16QAM system is.
Electromagnetic Shielding Characteristics of Polyaniline and Its Mixtures
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 2, 2001, Pages 293~298
EB-NMP free standing film is manufactured from NMP solution of polyaniline(emeraldine base EB). Also ES(emeraldine salt EB . HCl) film is manufactured by doping of EB-NMP film with 1 mole HCI aqueous solution. And EB-mixture films containing conductor(carbon black, graphite, Ag etc.) are prepared, In this study, electromagnetic interference shielding efficiency(EMI SE) of ES free standing film (
=5 S/cm, t=0.14mm) is 23~25 dB in the frequency range of 10 MHz~1 GHz. ES-mixture(carbon black, graphite, Ag etc.) films, polyaniline film doped camphorsulfonic acid(CSA) show higher EMI SE(30~34 dB, 36~42 dB, 44~52 dB, 34~43 dB) property than that of ES free standing film, respectively.
ISAR Imaging of Airplane-like Targets by Matrix Pencil Method
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 2, 2001, Pages 299~307
This paper presents a experimental study of Inverse Synthetic Aperture Radar(ISAR) imaging using Matrix Pencil(MP) method. A series of measurement for two types of target model was done in a Compact Range(CR)facility. The first target is a set of distributed slim cylinders to get a ISAR image of point-like scatterers. The second is UAV model representing a complex real target. The results show that ISAR images by MP method are better than by conventional FFT method under the realistic measurement conditions.
A Feedforward High Power Amplifier with Loops that can Reduce RX Band Noise as well as Intermodulation Distortion Signals
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 2, 2001, Pages 308~315
In this paper, a new power amplifier is proposed for reduction of amplified RX band noise signals as well as intermodulation distortion signals using feedforward technique. This power amplifier is implemented for IMT-2000 basestation TX frequency band. Both TX band intermodulation distortion signals and RX band noise signals are reduced by controlling variable attenuator, phase shifter and error amplifier. The proposed power amplifier, which contains two loops-intermodulation distortion signals cancellation loop and RX band noise signals cancellation loop, can provide duplexer with low TX path insertion loss for various wireless communication systems due to choice of loose RX attenuation characteristic. The principle of the proposed amplifier is described graphically based on the conceptual schematic diagram. A two-tone test for power amplifier is done at 2.14GHz with frequency spacing of 5MHz, and RX band rejection test is done over RX full band of 60MHz with 1.95GHz center frequency. Experimental results represent that the cancellation performance of intermodulation distortion signals and RX band noise signals are more than 3 1dB and 21dB, respectively.