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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 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
Selecting the target year
A Study on the Errors for the Improved Version of the Virtual Transmission-Line Model
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 10, 2002, Pages 971~981
An open-ended coaxial probe method has been considered as one of effective tools for measuring electrical properties of its contacted material without shaping and fitting. The measured reflection coefficient at the probe's end is able to convert into the corresponding complex permittivity by employing the improved version of virtual transmission-line model Presented by our lab already. But the error of complex permittivity converted by equivalent model increases as the operating frequency ascends high. The errors of complex permittivity in the open-ended coaxial probe can be yielded compositively by the imperfect contact or probe, manufacture error of probe and complex permittivity error of reference material etc. Therefore it is necessary to limit the problem to identify the error causes in high frequency. In this paper, the errors which are resulted from the measurement of reflection coefficient are removed by using the FDTD(Finite-Difference Time-Domain) method, the error causes are limited the conversion model problem. And the error study of the improved conversion model is performed from several viewpoints. At first, the local minimum of parameter to be calculated by the iteration method in the conversion model is checked. At second, the modeling of the equivalent model is checked in the frequency range. From this study, we know the valid range of the improved conversion model.
Design of Ku-band Channel Amplifier Engineering Model for Communication and Broadcasting Satellite Payload
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 10, 2002, Pages 982~988
This paper summarizes the design concepts and implementation of a Ku-band channel amplifier's engineering model for the communication and broadcasting satellite applications. The selected architecture uses the analog gain control for the FGM(Fixed Gain Mode) and the output level limiting using automatic loop control for the ALC (automatic level control) mode. The Ku-band channel amplifier incorporates several state-of-the-art components including voltage-controlled PIN diode attenuators, and various temperature-compensation circuits. The measured characteristics of the Ku-band channel amplifier are in good agreement with the expected performance. The results show a fixed gain control of 28 dB, and an automatic level control of 16 dB over operating temperature range. The designed engineering model could be used as a channel amplifier for Ku-band communication and broadcasting satellite payload system.
Adaptive Beamforming Technique of Eigen-space Smart Antenna System
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 10, 2002, Pages 989~997
This paper presents a new technique that enhances the performance of the smart antenna system especially in signal environments of wide angular spread by adopting a weight vector obtained from two eigenvectors of theautocovariance matrix of the received data. While the conventional beamformingtechnique employs only one eigenvector corresponding to the largest eigenvalue, the proposed algorithm uses two eigenvectors corresponding to the largest and second largest eigenvalue in such a way that it can be robust enough to the signal environments of wide angular spread. An efficient adaptive procedure is shown to verify that the optimal weight vector consisting of the two eigenvectors is obtained with a reasonable complexity(3.5
+ 12N) and accuracy. it is also shown in this paper that the numerical results obtained from the proposed adaptive procedure well agree with those obtained from a commercial tool computing the eigen-function of MATLABTM.
Design of Feedforward Linear Power Amplifier using Novel Injection Method of a Pilot Signal
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 10, 2002, Pages 998~1004
This paper reports a design of feedforward linear power amplifier using pilot tone for IMT-2000 band repeaters accepting multi-carrier. As this time pilot tone is applied to the circuit differently from the existing method. Only one pilot tone is used in both 1-st loop(IMD abstraction loop) and 2-nd loop(IMD cancellation loop) to cancell IMD signals automatically according to variation of frequency or power level of input signals. As an experiment, in range of 2110 MHz - 2170 MHz at LPA output power of
, IMD characteristics of over 20 dB was improved maintaining below -60 dBc considering respective 20 MHz. Therefore the supposed feedforward linear power amplifier can be used for linear power amplifier in IMT-2000 band repeaters.
On a Modified Structure of Taper Type Planar Power Divider/Combiner at 2 GHz
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 10, 2002, Pages 1005~1016
In this paper, a 2 GHz tapered shape of multiport power divider/combiner modified from the model published by  and adopted PBG(Photonic Band Gap) structure is proposed. Parameters determining electrical property of the circuit structure have been analyzed by HFSS simulation. For input matching, balance of output signals and phase linearity at each output port, one circular hole has been etched out on the circuit surface. 1:2 and 1:3 power dividers/combiners designed by this study have been compared with the same circuits designed by the method of  in terms of S-parameters. As a result, it has been found that tile modified structure and PBG of power divider/combiner have improved return loss more than 20 dB and another 18 dB. respectively, at 2 GHz.
Analysis of Radio-Wave Propagation Characteristics in Curved Tunnel
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 10, 2002, Pages 1017~1024
In this paper, we present the analysis of radio wave propagation characteristics in curved tunnels. Tunnel propagation models are performed in two cases which are using ray-tracing method for straight tunnels and geometrical optics extension to the standard hybrid waveguide model for curved ones. By regression analysis for measured power based on distance between the transmitter and the received antenna in tunnels that have 3.5 m
6 m cross section and limited wall depth path loss are 0.19 dB/m for straight section and 0.68 dB/m for curved ones. By comparing model analysis with measurement in tunnels, it has been shown that the simulated results of tunnel propagation models are similar to the measured values.
Design of Temperature-Compensation Circuits of Ku-band Amplifiers for Satellite Payload
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 10, 2002, Pages 1025~1033
This paper presents temperature-compensation circuits of Ku-band amplifiers for satellite payload. After carefully investigating design specifications of Ku-band amplifiers for satellite payload, we designed three types or temperature-compensation circuits, which are an active bias circuit, an attenuator control, and an ALC loop circuit. Our design technique demonstrates good agreement between measured and predicted results. These temperature-compensation circuits are suitable for Ku-band satellite payload active components, such as channel amplifiers, LNA and IF amplifiers.
Aperture Coupled and 3-D Transition Microstrip Line Fed Dual Polarization Rectangular Microstrip Antenna
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 10, 2002, Pages 1034~1039
In this paper, the design of a dual-polarization rectangular microstrip patch antenna with high isolation between two feeding ports excited by using both an aperture-coupled feed (port 1) and a 3-dimensional microstrip feed (port 2) is presented. From the simulation using the commercial program IE3D, the optimum values of the antenna parameters are investigated at both two feed structures and the optimum antenna is designed and fabricated. Experimental results confirmed that an bandwidth of the antenna is about 17 % and the isolation of two ports is great than 30 dB over all frequency bands.
Investigation of Power Bus Decoupling by the Screw Connection of the PCB to Chassis
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 10, 2002, Pages 1040~1047
In this paper, we investigated noise decoupling on the power bus by the screw connection, used to the mechanical join and grounding of the PCB ground to chassis. The screw connection penetrates the power bus and then it affects noise propagation on the power bus. To verify effect of the screw connection, we compare bare board with board having screws connection with 0.5 mm separation between power bus and chassis. From these results, we observed that the power bus noise was decreased about 5 dB at the frequency range from 0.1 GHz to 1 GHz. Also, we verified that a 4-layer PCB with signal trace had the better signal quality up to 600 MHz by the screw connection. Therefore, these results will be useful in designing to the high speed circuit and chassis.
TFBAR Lattice and Balanced Type Filter Topologies
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 10, 2002, Pages 1048~1053
In this paper, thin film bulk acoustic resonator(TFBAR) lattice and balanced type filter topologies are designed and fabricated. Aluminium nitride and platinum are used for piezoelectric material and top and bottom electrodes, respectively. Air-gap is placed to avoid silicon substrate loading effect and the performance of these lattice and balanced filters is compared with ladder filters. These filters have selectivity over 15 dB for lattice type and 30 dB for balanced type and reveal wider bandwidth of the ladder filters. For balanced type filters, minor tuning procedure is not needed and they are readily available for RF filter in wireless applications.
Modified Microstrip Filters Improving the Suppression Performance of Harmonic Signals
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 10, 2002, Pages 1054~1060
In this paper, a new parallel-coupled-line microstrip BPF(BandPass Filter) improving the suppression performance of 2nd harmonic signals is studied. Using the consecutive pattern in coupled-line, the desired passband performance is improved and harmonic passband signal is rejected. Recalculation of classical filter design parameters(space-gap between lines, line widths and lengths) is not required. That is, after using the classical design methodology for parellel-coupled-line BPF, new filters can be easily realized by inserting periodic patterns in coupled-line. To investigate the validity of this novel technique, order-3 Butterworth BPF centered at 2.5 GHz with a 10 % FBW(Fractional Bandwidth) and order-5 Chebyshev BPF centered at 10 GHz with a 15 % FBW were used. When five and three square grooves are used, over 30 dB harmonic suppression at 2nd harmonic is achieved in simulation and experiment.
Performance Analysis of a Smart Antenna Test-bed Operating in a IS2000 Environment
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 10, 2002, Pages 1061~1070
In this paper, we present a performance analysis of the smart antenna test-bed operating in a IS2000 1x through a test-bed that has been implemented on a DSP(TMS320C6711) board. The test-bed consists of a PC (for generating the RX data), beam-former(i.e., a stand-alone PCB for weight computation), and an interfacing module. The performance improvements compared to a normal base station system consisting of a single antenna are shown in terms the BER(bit error rate) in the wide-band CDMA channel.
Pressed PBG Ring Structure with a Wide Stopband
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 10, 2002, Pages 1071~1077
In this paper, we have studied the dependence of insertion loss of the pressed microstrip PBG ring consisting of coupled two microstrip lines. When the distance decreases, two or three attenuation poles are created by the coupling between the lines. Thus the pressed PBG ring exhibits a wide stop band and sharp cutoff characteristics.
Analysis of Stepped Impedance Lowpass Filter with Coupled Open Stubs
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 10, 2002, Pages 1078~1082
In this paper, we have studied the dependence of insertion loss of a microstrip stepped impedance lowpass filter with coupled open stubs. Coupling mechanisms in the filter depend not only on the transmission line width of the filter but also the gap width of coupled open stubs and three attenuation poles are created with the proper conditions. Also edge capacitance between open stubs play an important role in having three attenuation Poles. We verify the results by obtaining [S] matrices.
A 5.8 GHz High Gain MMIC Amplifier Considering the Coupling Effects among the Lumped Elements
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 10, 2002, Pages 1083~1088
A 5.8 GHz high gain MMIC amplifier was designed and fabricated. A HEMT was used as a active device and the spiral inductors and the metal insulator metal capacitors were used as the passive devices. To stabilize the high gain amplifier a RC feedback circuit was used. The amplifier has 4 stage and 31 dB measured gain. To prevent a oscillation by the coupling effects among the passive devices, the distance between the passive devices are made as far as possible. The via grounds were used to reduce the coupling effect between the input stage and the output stage.
Shipboard Active Phased Array Antenna System for Satellite Communications
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 13, issue 10, 2002, Pages 1089~1097
In this paper, the novel shipboard Active Phased Array Antenna(APAA) system for maritime mobile satellite communications is introduced. The antenna uses novel technologies like wide range hybrid tracking, single antenna elements with both of Rx and Tx, asymmetrical array structure, interference isolation between Rx and Tx, and error correction method from frequency scan effect. The antenna has single aperture for both of Rx and Tx with 32
4 two-dimensional array. The antenna has two beams. Its frequencies are 7.25 ~ 7.75 GHz for Rx and 7.9 ~ 8.4 GHz for Tx. The antenna gains are 35.4 dBi for Rx and 35.7 dBi for Tx, those are 54 % of efficiency. The electrically steering ranges are
of elevation direction and
of azimuth direction. The mechanical control ranges at hybrid tracking capability are continuous 360
of azimuth direction and
of elevation direction. The antenna has 2.2
of 3 dB beamwidth, -14 dB of sidelobe level, and 21 dB of cross-pol suppression. The antenna performance was measured by near field measurement set. Its system performance was tested on the ship motion simulator and with the satellite transponder simulator. The test result showed that its tracking error was within -3 dB from its peak gain under motion condition. The antenna system was tested by real modulated Direct Broadcasting Satellite(DBS) signals to check its communication processing function.