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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
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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Performance Improvement of Asunchronous DS-CDMA Systems with a Multistage Interference Canceller in the Presence of Timing and Phase Errors
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 1, 2001, Pages 1~10
In this paper, a multistage parallel interference canceller (MPIC) and a partial multistage parallel interference canceller (PMPIC) are employed as a technique for improving the performance of the asynchronous DS-CDMA systems. The degree of the effect of the timing errors and phase errors on the interference cancellation capability of two types of cancellers is theoretically analyzed and the computer simulation is performed to confirm the analytical results. From the results, the large performance improvement is obtained by employing MPIC and PMPIC with perfect synchronization over the conventional matched filter, and the performance improvement obtained by MPIC and PMPIC is very close to each other as the number of the stage of MPIC and PMPIC increases. When the timing errors and phase errors are considered (in the case of imperfect synchronization), the performance improvement reduces as the performance degradation at the first stage (no cancellation) has a bad effect on the decision statistics at each stage. However MPIC and PMPIC have the strong interference cancellation capability in spite of imperfect synchronization as the number of the stage increases. An interference canceller, which has the strong interference cancellation capability as well as lower complexity for the implementation, is needed for practical systems with timing errors and phase errors because the perfect synchronization is impossible. Therefore, the excellent tradeoff between complexity and performance offered by PMPIC makes it an attractive approach for practical systems.
A Study on Interference Analysis between Base Stations with FDD and TDD Modes for IMT-2000
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 1, 2001, Pages 11~17
This paper introduces an interference analyzer based on the statistical approach called the Monte Carlo methodology, which has been chosen as one of the interference analyzing techniques in ITU-R. Furthermore, using the interference analyzer developed in this paper with modified Hata model, computer simulation is performed to examine probability of interference affecting between the base stations with FDD and TDD modes for IMT-2000. Through the simulation results, it is confirmed that two different systems with FDD/TDD modes of same frequency bands can be simultaneously used in a cell without significant interference, under the parameter conditions specified in this paper.
Resonant Mode Analysis of Microwave Film Bulk Acoustic Wave Resonator using 3D Finite Element Method
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 1, 2001, Pages 18~26
In this paper, the resonant characteristics and modes of the film bulk acoustic wave resonator (FBAR) used in 1~2 GHz frequency region are analyzed by it's input impedance which was calculated by three dimensional finite element method formulated as eigenvalue problem using electro-mechanical wave equation and boundary condition. It was extracted that the resonant and the spurious characteristics considering the effects of electrode area and shape variation and unsymmetry of upper and lower electrode. Those effects couldn't be analyzed by on dimensional analysis, e.g. Mason equivalent model. The simulation result was confirmed by comparing with the simulation data from Mason model analysis and the measured data of the ZnO FBAR fabricated using micro-machining technique. Also, through the simulation of the area variations of FBAR, it was obtained that the optimum ratio of length and thickness is 20:1 and the minimum ratio is 5:1 to operate thickness vibration mode.
Micromachined Millimeter-Wave Cavity Resonators
Song, K.J. ; Yoon, B.S. ; Lee, J.C. ; Lee, B. ; Kim, J.H. ; Kim, N.Y. ; Park, J.Y. ; Kim, G.H. ; Bu, J.U. ; Chung, K.W. ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 1, 2001, Pages 27~36
In this paper, micromachined millimeter-wave cavity resonators ar presented. One-port and two-port cavity resonators at Ka-band are designed using 3D design software, HP
ver. 5.5 Cavity resonators are fabricated on Si substrate, which is etched down for the cavity, bonded with a Quartz wafer in which metal patterns for the feeding line coupling slot are formed. One-port resonator shows the resonant frequency of 39.34 GHz, the return loss of 14.5 dB, and the loaded
of 150. Two-port cavity resonator shows the resonant frequency of 39 GHz, the insertion and return losses of 4.6dB and 19,9dB, the loaded(
) and unloaded
) of 44.3 and 107, respectively.
A Study on Wideband Linear Power Amplifier Considering Delay Characteristics
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 1, 2001, Pages 37~43
In this paper, we designed a linear power amplifier considering its delay characteristics fur wideband operation. The power amplifier has the gain of 37 dB and is designed in 3-stage typ with 1W output power. The error amplifier has the gain of 55 dB and is designed in 4-stage typ. And directional coupler and power divider are designed. Vector modulator is used to adjust magnitude and phase of signal. A linear power amplifier, that is assembled with each modules, is designed considering the delay characteristics for 2.11~2.2 GHz. Its C/I3 ratio has been improved by B5 dB for bandwidth of 30 MHz.
VCO Nonlinearity Correction Technique using an Internal Reflection
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 1, 2001, Pages 44~49
In this paper, we propose a new technique to compensate for the VCO nonlinearity using only the returned beat signal whose spectrum contains the internal reflections and the targets simultaneously. In the case of a distance measurement system using single antenna, the reflections from the circulator and the antenna are much larger than the return signal from target. The beat signal by these reflections is at much lower frequency than that of the target, and the VCO nonlinearity can be compensated for using these signals. Indoor experiments were carried out and the results show marked improvement in the shape of range profile and the range resolution.
Design for the Circularly Polarized Microstrip Cross Dipole Array Antenna by Electromagnetic Coupled Technique
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 1, 2001, Pages 50~57
This paper describes a design for the circularly polarized microstrip EMC cross dipole array antenna with the wide bandwidth. To realize the characteristics of wide bandwidth and circular polarization, the electromagnetic-coupled cross dipole element is proposed. The optimum design parameters of a circularly polarized EMC cross dipole element are calculated by the FDTD and the Ensemble. To obtain the uniform aperture illumination of electric field in an array, offset technique that the cross dipole elements are alternatively arranged on center of the microstrip feed line is adopted. In 20-element array design, the calculated axial ratio and gain are about 0.1dB and 9.9 dBi at 12 GHz, respectively, The frequency characteristics of a fabricated 20-element array antenna are measured. The calculated results agree well with the measured ones.
A Broad-band Microstrip Patch Antenna for B-WLL System Applications
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 1, 2001, Pages 58~64
A microstrip patch antenna with B-WLL applications is designed and manufactured. To make a array antenna the size of patch antenna was miniaturized. A broad band is obtained by two additional parasitic elements, which are closely located to the main patch. The bandwidth of the manufactured antenna is 15% at the center frequency of 26.8 GHz. Radiation patterns are measured over a wide bandwidth.
Design of a Rceiver MMIC for the CDMA Terminal
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 1, 2001, Pages 65~70
This paper presents a Receiver MMIC for the CDMA terminal. The complete circuit is composed of Low Noise Amplifier, Down Conversion Mixer, Intermediate Frequency Amplifier and Bias circuit. The Bias circuit implementation, which allows for compensation for threshold voltage and power supply voltage variation are provided. The proposed topology has high linearity and low noise characteristics. Results of the designed circuit are as follows: Overall conversion gain is 28.5 dB, input IP3 of LNA is 8 dBm, input IP3 of down conversion mixer is 0 dBm and total DC current consumption is 22.1 mA.
A 3 Stage MMIC Low Noise Amplifier for the Ka Band Satellite Communications and BWLL System
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 1, 2001, Pages 71~76
A Ka Band 3-stage MMIC (Monolithic Microwave Integrated Circuits) LNA (Low Noise Amplifiers) has been designed and fabricated far the Ka band satellite communications and BWLL(Broad Band Wireless Local Loop)system. The MMIC LNA consists of two single-ended type amplification stages and one balanced type amplification stage to satisfy noise figure, high gain and amplitude linearity. The 0.15
pHEMT has been used to provide a ultra low noise figure and high gain amplification. Series and Shunt feedback circuits and λ/4 short lines were inserted to ensure high stability over the frequency range form DC to 80 GHz. The size of the MMIC LNA is 3.1mm
). The on wafer measured performance of the MMIC LNA, which agreed with the designed performance, showed the noise figure of less than 2.0 dB, and the gain of more than 26 dB, over frequency ranges from 22 GHz to 30 GHz.
EMC Design of Communication System on the Basis of EMC Design Rule
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 1, 2001, Pages 77~83
We analyzed the mechanism of EM emission in telecommunication system and extracted the dominant parameter in EMC design. The I/O cable, ventilation hole and shield design of chassis are important EMC design Issues in telecommunication systems. Because telecommunication systems have much more I/O cables than other electronic products, EMC design of I/O cable is very important in telecommunication systems. Therefore by the method of experimentation and simulation, EM coupling mechanism of I/O cable was analyzed and the design rule for low emission was extracted. On the base of these EMC design rules, EMC design of telecommunication system was executed without complex redesign or debug. The result obtained by these methods was shown in this paper.
Analysis of Current Density Distribution and In Vitro Exposur System fot ELF Exposed Cell Experiments
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 1, 2001, Pages 84~91
In in vitro cell experiments for the biological assessment of electromagnetic (EM) field, exposure system (ES) must be analyzed in terms of current density (J) and induced electric field intensity (E). Although in uniform B field, E and J in the sample medium are not distributed uniformly because of conductivity in sample dish. Thus, the precise estimation for E and J induced by uniform ELF within sample media is very important keys for successful in in vitro experiments. In this paper, we designed in vitro ELF ES with electromagnetic analysis using MATLAB simulator. Then we calculated from the measured B field to verify induced E & J distribution for random locations of cells within media in two cases of samples existence or not. ES with B field ranging from 0 to 20G consists of Helmholz coil and current generator based on the microprocessor. Also, we developed ELFES for each B field generation as uniform and non-uniform modes.
Numerically Efficient Evaluation of MoM Matrix in Conjunction with the Closed-form Green s Functions in Analysis of Multi-layered Planar Structures
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 1, 2001, Pages 92~98
When analyzing the scatting problem of multi-layered planar structures using closed-form Green's function, one of the main difficulties is that the numerical integrations for the evaluation of diagonal matrix elements converge slowly and are not so stable. Accordingly, even when the integration fur the singularity of type
, corresponding to the source dipole itself, is performed using such a method, this difficulty persists in the integration corresponding to the finite number of complex images. In order to resolve this difficulty, a new technique based upon the Gaussian quadrature in polar coordinates for the evaluation of the two-dimensional generalized exponential integral is presented. Stability of the algorithm and convergence is discussed. Performance is demonstrated for the example of a microstrip patch antenna.
The Design and Implementation of MCPA for IMT-2000 using Feedforward Linearization
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 1, 2001, Pages 99~106
In this paper, an 1-Watt amplifier for IMT-2000 was designed and fabricated using feedfarward method which has the highest linearity and wide bandwidth. Since feedforward is sensitive to surroundings for example heat, input power level, time and so on, adaptive controller using micro controller is adopted. We fabricated a HPA with 35 dB gain, 40 dBm of 1-dB compression point, and utilized variable attenuator and variable phase shifter using reflection type to cancel loop signal. From the measured results, the fo11owing facts were obtained, in signal loop, main carrier over 35 dB was suppressed and error signal over 30 dB is cancelled in error loop, IMD characteristics above 60 dBc were obtained.
Design and Analysis of PIFA with Frequency Operation
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 1, 2001, Pages 107~116
In this thesis, characteristics of compact PIFA are analyzed for operation in dual frequencies (dual-PIFA) as variety of parameters. The antenna is composed of two patches. These are operated in high frequency and low frequency. The dimension of experiential antenna is fixed for attaching at the handset. The variable parameters are dimension of small patch, length of shorting strip and dimension of folded conductor plate, the frequencies are 900 MHz and 1800 MHz. The compact antenna is implemented with 2-layer type, electric field intensities and radiation patterns are simulated. In order to analyze characteristics of a performance as variety of parameters, FDTD method is used.
Design of U-slot Array for OCS Base Station
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 1, 2001, Pages 117~124
In this paper, the design of a U-slot array antenna for PCS base station has been implemented and studied. The U-slot antenna is a single layer type with an antenna volume smaller but a bandwidth lager than the designs utilizing parasitic patches, which exceed 17 % bandwidth, for the probe fed case. Designed U-slot array antenna has stable radiation patterns and an average gain above 12 dB across the PCS frequency band. In this paper, through the designing of a U-slot array antenna, we have presented the availability for PCS base station antenna.
Design and Fabrication of a Dual Polarized Load-bearing Microstrip Antenna
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 1, 2001, Pages 125~135
4 microstrip antenna array is designed at 5.3 GHz and its characteristics are investigated with respect to the application in dual polarized synthetic aperture radars. The design is focused on the achievement of a wide bandwidth, a high polarization purity, a low loss, a good isolation and some mechanical requirements suitable for the application. The antenna is fed by a -3 dB tapered feed network, and is composed of dual polarized SSFIP (Strip-Slot-Foam-Inverted Patch) elements with honeycomb and shielding plane. Simulation results for the antenna array are presented and compared with measurements. It is observed that the antenna shows a bandwidth of 80 MHz, a polarization isolation better than 20 dB, an isolation of 40 dB, and good mechanical characteristics.
A Study on the PCB Design of a CAT.5E Modular Jacks Employing Field Cancellation Techniques
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 1, 2001, Pages 136~142
In this paper, a method of canceling and suppressing differential mode crosstalk noise signals caused by non-uniform coupling between two transmission lines in UTP (unshielded twisted pair) modular jacks is discussed. Differential mode crosstalk noise signals in balanced transmission lines with UTP modular jacks were suppressed, by applying field cancellation techniques to this modular jack. To verify an effectiveness of the field cancellation techniques, 8 pin modular jacks were made, and the NEXT (Near End Crosstalk) losses were measured to prove its applicability by the network analyzer(HP8720C) at 100 Mb/s.
Characteristics of Stacked Probe-Fed Sqare-Ring Microstrip Antenna
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 1, 2001, Pages 143~152
A method for miniaturization of microstrip patch antenna without degrading its radiation characteristics is investigated in this paper. It involves perforating the patch to form a microstrip square-ring antenna, and it's BW enhancement is investigated numerically and experimentally. A ring geometry introduces additional parameters to the antenna, and those are used to control impedances, resonance frequencies, and bandwidths. For a single square ring antenna, an increase of the size of perforation increases its input impedance, decreases the resonance frequency, and bandwidths. But it affects little on directivity of the antenna. To match the antenna to a transmission line and also enhance its bandwidth, the ring is stacked by a square patch or another square ring. Also numerically simulated results by the IE3D, and experimental data are compared for proof.
Efficient Calculation Method of the Green효s Function for the Rectangular Cavity
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 12, issue 1, 2001, Pages 153~159