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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
The Reverse Link Performance Analysis of cdma2000 Cellular System considering Adaptive Array Antenna
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 4, 2003, Pages 313~322
In this paper, the reverse link performance of imperfect power controlled cdma2000 cellular system that using array at a base station is analyzed, when MCGM beamforming algorithm and power control error is considered in shadowing. The blocking probability of the cdma2000 cellular system based on array parameters, E
0/ and interference statistics is calculated, and then the system capacity is calculated at a specific blocking probability. When the blocking probability is set 1 %, PCE(power control error) is 2 dB, M=2, 4, 8, 10, the capacity of cdma2000 is increased 2.3 ∼ 2.5 times higher than IS-95.
Method of Material Constants Extraction in Thin-Film Bulk Acoustic Resonator(FBAR) using Genetic Algorithm
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 4, 2003, Pages 323~329
In this paper, the method of material constants extraction in a thin-film bulk acoustic resonator(FBAR) using a genetic algorithm(GA) is proposed. The material constants are extracted from the input impedance of a FBAR by a GA optimizer. The characteristics of the FBAR input impedance affected by the material constants were studied to decide the fitness function for GA. As a result, the fitness was estimated by the series- and parallel -resonance frequencies and the FBAR bandwidth, as determined from the input impedance of the FBAR. A flowchart for the GA and a procedure fur the proposed extraction method are explained in detail, and the results of the material constants extraction are presented.
PAPR Reduction using Partial Transmit Sequences with Side Information of feedback Type
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 4, 2003, Pages 330~335
PTS（partial transmit sequences) has been widely studied for reducing the PAPR of OFDM signal, since it is flexible and any spectral regrowth may not occurred. A drawback of this PTS method should transmit the side information of the optimized phase factor for correct OFDM symbol recovery. A new idea of this paper is to insert the feedback type side information in the conventional PTS method. The simulation results show that the proposed scheme has the same PAPR reduction performance as the conventional PTS without side information and OFDM data are correctly recovered to get the required BER. Also, this method is independent of the channel characteristics and can be easily realized.
Optical Noise Reduction using a Solar Cell in a Wireless Optical Interconnection
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 4, 2003, Pages 336~342
In this paper, a new differential detector is introduced, in which a solar cell is used to reduce the low frequency interference from environmental optical noise. The solar cell also supplies electrical power to the detector circuit using the optical noise power. The DC voltage from the solar cell is used as a power supply to the detector, and the AC voltage is used to reduce the optical noise in a photodiode with the differential detection method. The signal to noise ratio was improved by about 20 dB.
Dual Band Antenna for GPS and Satellite Radio System
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 4, 2003, Pages 343~350
Circularly polarized-dual band antenna for GPS(Global Positioning System) and satellite radio system is developed and measured. Both circular polarization and overall antenna dimension reduction are achieved by placing a partially filled high-permittivity substrate under radiating edges. The bandwidth is also improved by choosing an optimal geometric configuration with a partially filled high permittivity substrate. The proposed antenna can be installed on moving vehicles or ships.
A Small Microstrip Patch Antenna
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 4, 2003, Pages 351~355
In this paper, rectangular patch antenna is miniaturized by changing the middle of patch into narrow microstrip line except the edges of the patch where the fringing field occurs. Miniaturized rate, gain, bandwidth, radiation pattern of suggested antennas were compared with general square and rectangular microstrip antennas by using simulator Ensemble. As a result, it reduces the dimension of antenna by 44 % and improves the characteristic of x-pol by 40 dB as an advantage when compare with square microstrip antenna while it reduces bandwidth.
RF Predistortion Techniques using 2nd Harmonics and Difference Frequency for Linearization of Power Amplifier
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 4, 2003, Pages 356~362
In this paper, we propose a predistortion technique which uses a novel combination of the second harmonic technique and the difference frequency technique to achieve independent control of the 3rd and 5th order intermodulation products generated by the PA. The second harmonic and difference frequency terms are generated using an envelope detector and two frequency multipliers. The RF predistorter has capability to independently control of the 3rd and 5th order intermodulation products so that high power amplifier is optimized for linear characteristics. From the measurement results, over the frequency band 2137.5 MHz to 2142.5 MHz, ACPR reduction of 11 dB is obtained for a single 30 dBm W-CDMA carrier.
The Multi-Mode Circular Horn Antenna for the Transfer of High Power
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 4, 2003, Pages 363~368
In this paper, the characteristics of the horn antenna for the high power transfertation system is stuided and several kinds of a horn antenna are compared and finally a conical hem antenna using multi-mode is proposed. In the high power system, the efficiency of power transfer is very important. Therefore the feeding hem of a reflector must have a circular symmetric radiation pattern. And the side lobe must be suppressed to reduce a spillover power loss and interference. By using multi-mode in a circular hem antenna, the whole length can be shorter and the radiation pattern can be adjusted according to the shape and direction of a reflector. This is confirmed by the experiments.
Design and Fabrication of Ka-Band NRD Guide Filter with Newly Designed Inductive Post Structure
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 4, 2003, Pages 369~376
In this paper, Ka-Band NRD guide band pass filter with newly designed inductive post structure is proposed and analyzed with its test results. Generally, millimeter-wave filters are very sensitive in their physical dimensions, hence, it is requires extreme precisions of several micron so as to get the designed performance. In case of common NRD Guide filter with air gap coupled structure, it is fabricated with dielectric blocks coupled via air gap. In these structures, however, it was not easy to fabricate and to process of each NRD guide dielectric resonator blocks using PTFE, so it was almost impossible to assemble with several microns in precision. In this our research, however, each dielectric resonators are coupled with a pair of inductive metal post, so all resonators are located in a single NRD Guide. The dielectric parts between two pairs of posts are operated as resonators of each stage, and the positions of the post decide the couplings between resonators. The structure we suggested is suitable fur mass production, because it is very simple and easy to process. As a result of measurements, designed NRD guide inductive post filter has a superior performance. The center frequency is 39.475 GHz with 350 MHz bandwidth, insertion loss is less than 1.8 dB, and the return loss is below than -18 dB.
Measurement of Transfer Impedance on Shielded Multiconductor Telecommunication Cables using IEC 96-1 Line Injection Method
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 4, 2003, Pages 377~383
As the high-speed data communications such as xDSL using the existing copper cable come into wide use, the electromagnetic coupling characteristics of telecommunication cables become more significant. In order to describe the screening performance of telecommunication cable, the transfer impedance of cable shield is required. This paper describes the transfer impedance for two types of telecommunication cables using the line injection method of IEC 96-1. Results are analyzed to show how the materials of cable shields, the positioning of the injection line and of the inner conductor of the CUT(Cable Under Test) affect the value of transfer impedance. We then propose the transfer impedance model of telecommunication cable based on the measurements.
Cavity-type and Parasitic-type Couplings through a Harrow Slit in A Parallel-Plate Waveguide with a Conducting Strip
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 4, 2003, Pages 384~392
In this study, the electromagnetic coupling through a narrow transverse slit in the upper wall of a parallel-plate waveguide(PPW) covered by a dielectric slab with a nearby conducting strip on the slab is considered. Two contrastive coupling phenomena, cavity-type and parasitic-type, observed in the geometry have been distinguished by differences in the resonant strip lengths and offset positions, induced strip current, radiation pattern, frequency bandwidth, and electromagnetic field distributions near the coupling slit.
A Study on Input Multiplexer for Ku-Band Satellite Transponder
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 4, 2003, Pages 393~400
This paper deals with the design and manufacturing technique of EQM(Engineering Qualification Model) of input multiplexer(IMUX) for the Ku-band satellite transponder. Channel dropping method by circulator chain structure is adopted for demultiplexing each channel. External equalizers are attached behind channel filters fur reduction of group delay variation and amplitude variation simultaneously. Both channel filters and equalizers adopted dual-mode technique in design f3r mass and volume reduction. Channel filters are designed to have 8-pole elliptic response and equalizers to be of 2-pole reflection type. For good temperature stability characteristics, INVAR36 material is used for channel filters and external equalizers. Vibration test, Thermal Vacuum Test, and EMC test have been performed on input multiplexer and it is shown to be suitable for Ku-band satellite transponder.
A Study on a New Broadband 180° Phase Shifter using the Network with Great Phase Dispersive Characteristics
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 4, 2003, Pages 401~412
In this paper, a broadband phase shifter structure using a new switched network was proposed. A new reference network is composed of coupled lines and 45
open and short stubs, which are shunted at the edge points of a main line, respectively, A delay network is composed of only a standard transmission line. It is possible to design a broadband 180
phase shifter that phase dispersive characteristics by an impedance ratio R of coupled lines and greater phase dispersive characteristics by characteristic impedances Zm, Zs of a main line and stubs are used together. By considering a structure symmetry, the even and odd mode analysis was performed to obtain theoretical S-parameters of the proposed phase shifter. Also, through computer simulation on the basis of derived equations, design graphs were presented to optimally design a 180
broadband phase shifter. Design graphs provide the values of characteristic impedances Zm, Zs, and I/O match and phase bandwidths. To verify electrical performances of the broadband phase shifter proposed in this paper, low different 180
phase shifters, operated at the center frequency 3 GHz were designed and fabricated using design graphs, and were experimented. One of them was designed as a standard Schiffman structure to compare with electrical performances. Measured results of each phase shifter to satisfy simultaneously design conditions of I/O match （VSWR=1.15:1) and maximum phase deviation(
) were well in agreement with corresponding simulation results over impedance match and phase error bandwidths, and showed broadband characteristics.
Correction of Beam Direction Error caused by Frequency Scan Effect in Active Phased Array Antenna for Satellite Communications
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 4, 2003, Pages 413~420
In this paper, the correction method of antenna beam direction errors is introduced which caused by frequency scan effect in active Phased may antenna for satellite communications. The antenna makes the beam directional error from frequency scan effect when it has dual beam may structure with asymmetrical series connection, their frequencies are different and for from each other, their 3dB beamwidth is narrow, and scan range is wide. By proposed equations, estimated beam direction error angles can be calculated and active phase shifter control values also can be calculated to compensate them. In this paper, the active phased array antenna system was fabricated to measure beam direction errors both before and after correction, which has dual beam from 32
4 main level array and 4
2 second level array, frequency deviation 500 MHz max.(6.7 %) at 7.25 GHz∼7.75 GHz ranges, 0
nm ranges, and 35.6 dBi gain with 2.2
3 dB beam width. Its beam direction error by frequency san effect which was 2.5
max., was reduced to 0.2
max. after correction. This was 7 dB improvement of signal loss. The active phased array antenna can accurately track the target satellite for communications by this proposed correction method.
A Study on SAR Variation by Folding Angle and EMI Paint Distribution of Case for Mobile Handsets
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 14, issue 4, 2003, Pages 421~430
In this paper, we propose a method to consider SAR(Specific Absorption Rate) at beginning stage of handsets development. First, simulation was carried out with changing folding angle from 150
. Simulation results show that SAR value is decreased with decreasing the folding angle. When folding angle is 142
, error between simulation and measurement results is about 3.95 %. Second, we made some experiments with EMI (Electromagnetic Interference) paint, and its results show that different pattern of EMI paint have different SAR values. After removing EMI paint at the lower part of antenna feeding point, we got the decrease efficiency of 15.46 % for SAR value. When we applied zigzag painting pattern, we got the highest SAR decrease efficiency.