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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 14, Issue 12 - Dec 2003
Volume 14, Issue 11 - Nov 2003
Volume 14, Issue 10 - Oct 2003
Volume 14, Issue 9 - Sep 2003
Volume 14, Issue 8 - Aug 2003
Volume 14, Issue 7 - Jul 2003
Volume 14, Issue 6 - Jun 2003
Volume 14, Issue 5 - May 2003
Volume 14, Issue 4 - Apr 2003
Volume 14, Issue 3 - Mar 2003
Volume 14, Issue 2 - Feb 2003
Volume 14, Issue 1 - Jan 2003
Selecting the target year
A Study on Optimization of a Multi-Layered Metallic Disk Array Structure for Shaping of Flat-Topped Element Patterns
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 10, 2003, Pages 985~995
In this paper, a study on optimization of three dimensional multi-layered metallic disk array structure(MDAS) excited by circular waveguides was performed to shape efficient flat-topped element patterns(FTEP) of
beam width. Each radiating element of the MDAS is composed of input, transition and radiation circular waveguides and finite metal disks stacked on radiation circular waveguide. It has an array structure of a hexagonal lattice appropriate for the conical beam scanning. The analytic algorithm for the MDAS was proposed and the code was also programmed using it. Optimal design parameters of the MDAS were determined through the optimal simulation process to obtain
FTEP. Also, bandwidth characteristics for FTEP and reflection coefficients of the MDAS were investigated and, as the results, it was shown that the MDAS could shape good FTEPs of
beam width in main planes at least within a 5.6 % frequency band.
MMIC Transversal Filter using Multiple-Coupled-Line Directional Couplers
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 10, 2003, Pages 996~1003
There are critical drawbacks in fabricating MMIC transversal filters because the length of the conventional transversal filter structure is much longer than the width. In order to solve this structural problem, a transversal filter using multiple-coupled-line directional couplers which can achieve tight coupling is proposed. The length of the proposed transversal filter can be made short using multiple-coupled-line couplers so that the structure of the proposed filter is applicable to MMIC technology. Because of the dielectric and conductor losses, the excited signal at the input port becomes smaller when it progresses through each directional coupler. Therefore, the strength of the coupled signals at the latter directional couplers becomes smaller than the designed one and this, in turn, gives rise to performance aggravation. A modified coupling coefficient formula to prevent frequency characteristic degradation is introduced. The proposed filter structure and the design method are verified by the calculated result and 3D full-wave analysis.
Design of Tight Coupled 1/4 Wavelength Backward-Wave Directional Coupler using Coupled Lines with Finite Metallization Thickness
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 10, 2003, Pages 1004~1010
In this paper, the 1/4 wavelength backward-wave directional coupler using coupled lines with finite metallization thickness is described. A mode-matching method, simple and fast approach to the quasi-static analysis, has been used to analyse this structure. The numerical results show that it is possible to overcome the disadvantages of weakly coupling, low directivity, and narrow strip distance non-realizable in the case of 1/4 wavelength backward-wave directional coupler with zero thickness conductor. It is also revealed that thicker metallization causes longer coupler length in the case of backward-wave symmetrical parallel coupled line directional coupler. The finite metallization thickness can be a new parameter for tight coupling in the design of backward-wave directional couplers, which enables us to design more accurate properties of monolithic microwave integrated circuits.
A Study on the Method to Satisfy the 2-Tone and CDMA Intermodulation Distortion Characteristics Simultaneously
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 10, 2003, Pages 1011~1016
In this paper, we investigate the relationship between the intermodulation signal of 2-tone and CDMA spurious emission of HPA. And confirm that the fifth IMD signal of HPA has more important effect upon CDMA ACPR characteristics than the third IMD signal. We present the method for the power amplifier to satisfy the 2-tone and CDMA specification simultaneously, and that is to use the predistorter for improving the third IMD signal of 2-tone for the power amplifier which is tuned to satisfy the CDMA specification and not to satisfy the 2-tone specification. The result by using the method which is presented from this paper shows that the ACPR is improved about 2 dB for CDMA 1FA(frequency allocation) signal and the third IMD signal is improved about 20 dB for CW 2-tone signals and we confirmed the specification is satisfied simultaneously.
Management Strategies for Electromagnetic Fields in Electric Power Lines
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 10, 2003, Pages 1017~1023
Recently, the use an electric apparatus has brought into concerns about health risks from exposure to electromagnetic fields. During the last 2 decades, a number of epidemiological studies have explored the association between childhood leukaemia and residential exposure to power-frequency electromagnetic fields. Several studies have suggested that there is a small excess leukaemia risk with magnetic field exposure above 2 mG. A number of governmental and international organizations have developed exposure gudelines. The most rigid regulation with exposure levels for the elementary school and hospital has been enacted by Switzerland. Although there is no convincing supportive laboratory evidence, and the absence of a plausible biological mechanism of disease causation limits, governments are increasingly called on to adopt precautionary approaches to regulating electromagnetic field exposures. The government would need to establish the policy for electromagnetic fields and continually to be concerned about possible health risks from exposure to electromagnetic fields.
Mode-Matching Analysis for Complex Antenna Factors of Circular Top-Hat EMI Monopole Antennas
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 10, 2003, Pages 1024~1029
This paper presents the complex antenna factor of a top-hat EMI monopole antenna for measuring time domain electromagnetic fields. The approach is facilitated by adding a artificial parallel ground plane above the monopole antenna. This allows use of cylindrical harmonic field expansions in each of three subregions enclosed by the two ground plane. The results show that the complex antenna factor of the top-hat monopole antenna does not diverge at low frequencies. When compared with a monopole antenna, the top-hat monopole antenna has broadband characteristics. In order to verify the availability of the mode-matching method, the input impedance of the antenna were compared with experiments.
Anti-Interference Analysis of IS-OFDM using the Frequency Diversity
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 10, 2003, Pages 1030~1035
In this paper, we compare the performance of IS-OFDM(interference suppressing orthogonal frequency division multiplexing) system with that of the conventional OFDM system. Each parallel branch symbol of IS-OFDM is multiplied by the orthogonal sequence and distributed into all sub-carriers. Then, each sub-carrier transmits information composed of the symbol components of all parallel branches in the given frame. The structure of IS-OFDM shows the frequency diversity characteristic. Therefore, IS-OFDM can be robust to the narrowband interference. BER performances are found in the narrow-band interference and a harmonic noise channels. When JSR(Jamming to signal ratio) increases from -10 dB to +10 dB in the constant interference bandwidth, IS-OFDM outperforms the conventional OFDM and the BER difference between IS-OFDM and OFDM is reduced as JSR increases. Also, the similar properly can be shown when interference bandwidth increases at the constant JSR. In the harmonic noise channel, we can find the good performance of IS-OFDM when the h-rate(harmonic noise bandwidth to signal bandwidth ratio) increases from 0.01 to 0.8. So, simulation results show that the IS-OFDM is more robust to the interference than the conventional OFDM.
Novel Lumped Element Backward Directional Couplers Based on the Parallel Coupled-Line Theory
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 10, 2003, Pages 1036~1043
In this paper, novel lumped equivalent circuits for a conventional parallel directional coupler are proposed. This novel equivalent circuits only have self inductance and self capacitance, so we can design exact lumped equivalent circuit. The equivalent circuit and design formula for the presented lumped element coupler is derived based on the even- and odd-mode properties of a parallel-coupled line. By using the derived design formula, we have designed the 3 dB and 10 dB lumped element directional couplers at the center frequency of 100 MHz and 2 GHz, respectively a chip type directional coupler has been designed with multilayer configurations by employing commercial EM simulator. Designed chip-type directional couplers have a 3 dB-coupling value at the center frequency of 2 GHz and fabricated lumped directional coupler on fr4 organic substrate has a 3 dB, 10 dB-coupling values at the center frequency of 100 MHz. Excellent agreements between simulation results and measurement results on the designed directional couplers show the validity of this paper. Furthermore, in order to adapt to multi-layer process such as Low Temperature Cofired Ceramic (LTCC), chip-type lumped element couplers have been designed by using this method.
The Compact Hairpin-Shaped Duplexer using a BMT Substrate with a High Dielectric Constant
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 10, 2003, Pages 1044~1051
In this paper, a compact planar microwave duplexer on the high dielectric substrate is presented. As the Ba(Mg
(BMT) has good dielectric performances with a high dielectric constant of
r/=23, it is suitable to apply to a printed circuit board fur reducing its circuit size. The BMT substrate is fabricated by using a tape casting fabrication process, and circuit patterns are screen-printed on it by suing silver paste. The open-loop ring type duplexer is designed and implemented on the BMT substrate, and it achieves the smaller size by 80% than one on a commercial substrate(
r/=6.15) without degenerating its performance. Therefore the proposed BMT substrate has provided the miniaturization of the duplexer, moreover it can make a contribution towards reducing the size of microwave passive circuits.
A Design of Two Layer Re-entrant Microstrip Directional Coupler Improving Coupling and Isolation
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 10, 2003, Pages 1052~1059
In this paper, we proposed the directional coupler using two layer microstrip substrate which is improved coupling and isolation. Also, we notified a design method. Modified re-entrant mode coupler is the structure added to the aperture on the ground plane in order to improving the coupling value. And, by adding to slits on the floating conductor, this structure has good performance in isolation, VSWR according to S
11/, and phase difference. As a result, proposed re-entrant mode microstrip directional coupler has about 1.5 dB more higher coupling and 20 dB more higher isolation than conventional coupler. And because this coupler has good performance in phase difference, it can be used multi-section coupler.
Design of Ka/Ku Band Frequency Selective Surface with Triple Square Loop Slot Array
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 10, 2003, Pages 1060~1070
The frequency selective surface for use in Ka/Ku band parabolic antenna of domestic satellite communications is proposed. The frequency selective surface structure consists of the infinite periodic arrays of the triple square loop slot element with narrow width on the honeycomb structure of multi-layered dielectric. The frequency selective surface is fabricated and measured. The good agreement is obtained between theory and experiment. It is demonstrated that the frequency selective surface passes 14/12 GHz band wave while reflecting 30/20 GHz band wave as required.
Small Broadband Phased Array Antenna with Compact Phase-Shift Circuits
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 10, 2003, Pages 1071~1078
In this paper, the planar, compact, and broadband phased array antenna system for IMT-2000 applications has been investigated. Two methods far designing a low-cost and low-complex beam-farming network are proposed. First, a new compact and broadband phase shifter with continuously controlled phase bits is designed by using parallel coupled lines. Second, its equivalent phase delay line is suggested to be capable of replacing the complex phase shifter with a reference phase bit on a phased array antenna. For the purpose of achieving the broadband system, in addition to the broadband phase shifter, a wide-slot antenna with a ground reflector is utilized as an element antenna. Therefore, the phased array antenna system has achieved compact size, broad bandwidth, and wide steering angle, although it has low complexity and low fabrication cost. The 3
1 phased array antenna system has a compact size of 1.6 λ
l.6 λ, which is the sufficient ground plane of the wide-slot antenna. Experimental results present that the S
11/ has less than 15 dB within the band and its radiation patterns on an E-plane have the capability of steering an antenna beam from -29
Detection and Estimation of Multiple Faults on a Coaxial Cable Based on TFDR Algorithm
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 10, 2003, Pages 1079~1088
In this paper, we propose a high-resolution time-frequency domain reflectometry technique as a methodology of detection and estimation of faults on a wire. This method adopts the time-frequency cross correlation characteristics of the observed signal in both time and frequency domains simultaneously. The accuracy of the proposed method is verified with experiments using a RG type coaxial cable and comparing it with traditional time domain as well as frequency domain reflectometry methods. It is clearly shown here that the proposed algorithm produces excellent results compared to the conventional methods for single as well as multiple fault cables.
Design of Omnidirectional Antennas Composed of the Parabolic Reflector
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 10, 2003, Pages 1089~1095
In this paper, the 26 GHz band omnidirectional antenna that produces an isotropic radiation pattern in the azimuth plane and a directive radiation pattern in the elevation plane was designed by using reflector antennas. To investigate the reliability of the designed antenna, that was analyzed by using the aperture field method and the calculated value was compared with the measured value. An good agreement was achieved between the calculated characteristics and the experimental performance. We found that the designed antenna in this paper can be used as the omnidirectional antenna with reflectors and the analysis method in this paper can be used for the analysis of this type antenna.
Analysis of Transient Electromagnetic Scattering from 3-Dimensional Dielectric Objects by using Time-Domain PMCHW Integral Equation
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 10, 2003, Pages 1096~1103
In this paper, we analyze the transient electromagnetic response from three-dimensional(3-D) dielectric bodies using a time-domain PMCHW(Poggio, Miller, Chang, Harrington, Wu) formulation. The solution method in this paper is based on the Galerkin's method that involves separate spatial and temporal testing procedures. Triangular patch basis functions are used for spatial expansion and testing functions for arbitrarily shaped 3-D dielectric structures. The time-domain unknown coefficients of the equivalent currents are approximated by a set of orthonormal basis functions that are derived from the Laguerre polynomials. These basis functions are also used as the temporal testing. Numerical results involving equivalent currents and far fields computed by the proposed method are presented.
I/Q Gain and Phase Imbalances Compensation Algorithm by using Variable Step-size Adaptive Loops at Direct Conversion Receiver
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 10, 2003, Pages 1104~1111
The paper presents an algorithm for the compensation of gain and phase imbalances to exist between I-phase and Q-phase signal at direct conversion receiver. We propose a gain and phase imbalances blind equalization compensation algorithm by using variable step-size adaptive loop at direct conversion receiver. The blind equalization schemes have trade-off between convergence speed and jitter effect for the compensation of gain and phase imbalance. We propose the variable step-size adaptive loop method, which varies the loop coefficients according to errors, for recovering these problem. By using variable step-size adaptive loops, we propose to speed up the convergence process and reduce the jitter effect and simulation results show that the algorithm compensates signal loss and speeds up convergence time.