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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 9, Issue 6 - Dec 1998
Volume 9, Issue 5 - Oct 1998
Volume 9, Issue 4 - Aug 1998
Volume 9, Issue 3 - Jun 1998
Volume 9, Issue 2 - Apr 1998
Volume 9, Issue 1 - Feb 1998
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FDTD Calculation for SAR Induced in a Head Model by the Electromagnetic Fields Irradiated from a Cellular Phone
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 9, issue 1, 1998, Pages 1~7
The near field radiated from the monopole antenna of the cellular phone was calculated by using the modified finite difference time domain algorithm derived from the integral form of Maxwell's equations. Substituting the near field value into the differential form of Maxwell's equations, SAR's distribution in the human head was obtained. The human head was simulated by a model of 800,000 block cells with dielectric constant and conductivity. The cell size was taken to be 0.5 cm. the transmitted power of the cellular phone was assumed to be 0.6 watts at the frequency of 833 MHz. The distance between the head and the cellular phone was 2.0 cm, the maximum SAR induced in the human head was about 1.5 W/kg and was below the IEEE's upper safety limit of 1.6 W/kg.
A Study on the Bandwidth Improvement of the Microstrip Antenna for Mobile Communications
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 9, issue 1, 1998, Pages 8~15
In this paper, to improve the bandwidth of microstrip antenna, we discussed parasitic patch structure coupled capacitively at radiating slot. To reduce the overal size of antenna,
/4 short structure is accepted instead of
/2 patch. Since ground plane is reduced, backward radiation is occurred. The characteristics of the designed antenna is evaluated, based on the transmission line model and the aperture analysis method. And by computer program the radiation pattern and return loss are evaluated. As simulation results, backward radiation is -15 dB. Bandwidth of constructed antenna is 167 MHz at the resonant frequency of 2.45 GHz, which is very broad, compared to conventional microstrip antennas. Therefore the proposed antenna will be suitable for very wide bandwidth communications.
Compensation for laser chirping and chromatic dispersion using optical equalizer in fiber optic transmission systems
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 9, issue 1, 1998, Pages 16~24
In a high speed long haul fiber optic communication system using modulation, fiber chromatic dispersion and laser chirping can cause serious performance degradations. In this paper, the combined effect of laser chirping and chromatic dispersion on the per- formance of 2.5[Gbps] rate lightwave systems operating at a wavelength of 1550[nm] was investigated. Also we used an optical equalizer to compensate the laser chirping and fiber dispersion, and knew that the receiver sensitivity was improved by about 2 ~ 4[dB].
Manufacture of a single gate MESFET mixer at PCS frequency band
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 9, issue 1, 1998, Pages 25~33
In this paper, we describe a single-gate MESFET mixer at PCS(Personal Communication Service) frequency band. The PCS frequency band is 1965~2025 MHz in FR and 140 MHz in IF irrespectly. The design of the mixer was executed by microwave simulator, EEsof Libra. The matching network is consisted of rectangular inductor, MIM capacitor and open stub. The ma- nufacture work was accomplished by the micro-pen and wedge-bonder. The mixer showed
dB of conversion gain,
dB of RF reflection coefficient and 57.83 dB of LO/IF isolation at 10 dBm of LO power when LO frequency is 1855 MHz. When this mixer is used at PCS terminal, IF-amplifier which compensates the conversion loss of diode mixer may be omitted.
The analysis of sleeve monopole antenna by lumped-element equivalent circuit
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 9, issue 1, 1998, Pages 34~42
This paper discribes an analysis for the sleeve monopole antenna with single sleeve. The structure of the proposed antenna is very simple. Therefore, it is very economical in terms of manufacturing and installation which makes it convenient for either portable or mobile use by making an up-and-down type antenna. In the method of analysis, instead of the complex electro- magneticapproach, we used a lumped element equivalent circuit derived from the information about the electrical dimensions and the resonance characteristics of the antenna. An error between a resonant frequency by lumped-element circuit analysis of the proposed antenna and a measured one by an experiment is below 0.9%. It is shown that the theoretical and experiment results are little different.
The Performance Analysis of the Initial Synchronization for the Direct Sequence Spread Spectrum Communication under the Rician Fading Channel
Lim, Myoung-Seob ;
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 9, issue 1, 1998, Pages 43~51
In this paper, the performance about the CDMA inital synchronization under the Rician fading channel, which is actively studied as a CAI for IMT2000(FPLMTS) is analyzed. Through the performance analysis with the double dwell serial search code acquisition, the minimum mean initial synchronization acquisition time vs signal detection threshold value and first dwell duration time respectively with parameters of false alarm probability, detection probability and test PN chips is presented and the results show the mean initial synchronization acquisition time is increased with lower slope than Rayleigh fading as the threshold value of the initial synchronization acquisition decision is increased.
A study on the rain attenuation prediction model using effective permittivity
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 9, issue 1, 1998, Pages 52~59
We calculated the wave attenuation due to rain using the effective permittivity of the air with raindrops. The effective permittivity depends on the complex permittivity of rain drop and the fractional volume occupied by the raindrops. We calculate the complex permittivity of rain drop and the raindrops' volume using Marshall-Palmer Rain drop size distribution. The rain attenuation calculated by effective permittivity is compared with the results of ITU rain attenuation model, and the two rain attenuation models have a very close agreement. The effetive permittivity model underestimates the rain attenuation under 50 GHz, and overestimate at the frequencies under 50 GHz copmpared with the ITU model.
The analysis on the effect of rician fading and lognormal shadowing in microcellular mobile radio system using outage probability
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 9, issue 1, 1998, Pages 60~71
The propagation environment is effected by Rayleigh fading, Rician fading, path loss and lognormal shadowing in microcellular mobile radio system. In these surroundings we analysed the performance on received Rician signals among L Rician interferers and the characteristics of lognormal shadowing for various parameters such as reuse distance, cluster size, signal to interference power ratio and protection ratio using outage probability. We also studied various channels Rayleigh signal and Rician interferer, Rician signal and Rayleigh interferer, Rician signal and Rician interferer and so on using outage probability. The theoretical extention and computer simulation effectively analysed the characteristic of lognormal shadowed Rician channel.
Estimation of Characteristics of Meteor Burst Radio Path Using Reference Path Comparison Method
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 9, issue 1, 1998, Pages 72~86
This paper introduces a simple yet accurate method to predict burst rate and durence expected in a meteor burst communication path in question by comparing its path specifications to those of an exiting path. In this article, the authors analyze the method to derive the burst rate and duration by comparing span distance, frequency, antenna gain, transmitting power and thre- shold level to those of a existing path selected for the reference. the authors further report the result of experiments made for two difference paths; 750 km path and 1,200 km path to Hamamatu Japan and Hatinohe Japan from Kyongsan korea respectively. The occuring rate and average length of the bursts measured on the experiment paths show fairly good agreement with the analysis.
An analysis of tunable characteristic for magnetically tunable E-plane waveguide filters
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 9, issue 1, 1998, Pages 87~97
This paper describes an analysis of tunable characteristic for magnetically tunable E-plane type finline filter on a ferrite substrate. The proposed design is based on using of quarter wavelength transmission line for compensating the negative length transmission line of end K-inverters of E-plane type waveguide filters and the tunable characteristics of designed filters are analyzed. The analysis results of filter and inverter structure loaded with finline on a ferrite substrate are obtained using the edge based finite element method including higher order mode effects. The X-band experimental results for bilateral and unilateral finline magnetically tunable E-plane type waveguide filters agree well with the simulated data.
Implementation of DS/SS(FM-DS/SS) system using FM
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 9, issue 1, 1998, Pages 98~107
For implementation of FM-DS/SS system. This paper has analyzed SO(Synchronous Oscillator) being oscillated by the motivation of injected signal. Transmitter has adopted FM-DS/SS modulation method using RF output-signal of FM. Receiver is used SO to demodulation of FM-DS/SS and applied sliding correlator for synchronization of PN clock. As a result of the inspection, SO presented stable lock ability in spite of doppler apperance and proved the synchronous properties of it in the FM-DS/SS system.
Analysis and Fabrication of Waveguide E-Plane Metal Insert Bandpass Filter for Milli-meter Waves
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 9, issue 1, 1998, Pages 108~114
This paper presents the design and fabrication of waveguide E-plane metal insert bandpass filter for milli-meter waves which is analyzed transmission characteristics by calculating the generalized scattering matrix using mode-matching method. The bandpass filter was fabricated to verify the proposed method by the WR-34 rectangular waveguide to operate in 30.085 ~ 30.885 GHz. The fabricated waveguide E-plane metal insert band- pass filter was established the fact that it is so adaptive for milli-meter waves due to the measured data closely consistent with the results of analysis using mode-matching method, that is, the maximum value of insertion loss is 0.8 dB and the return loss is below -15 dB.
A study on the sharing between NGSO/MSS service link and existing fixed-service microwave system
The Journal of Korean Institute of Electromagnetic Engineering and Science, volume 9, issue 1, 1998, Pages 115~125
This paper examined the feasibility of adding a new NGSO/MSS(Non-Geostationary orbit/Mobile satellite service) service link to a frequency band which is already allocated to fixed-service microwave(M/W) system. To achieve this goal, the NGSO/MSS handset performance under the influence of the M/W multiple stations and the influence of handsets on the M/W station were both analyzed. Sharing criterions were also obtained by means of coordination contour in the former case, and handset capacity in the latter case. As the results, it was proven that sharing was feasible only when the vertical distance between handset and trendline was above 4 km except front and back points of M/W antenna bore sight under influence of 9 hops(the distance between hops = 50 km) M/W system on the NGSO/MSS handset, and only when the capacity of handset was below
under influence of handsets on the M/W station.