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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of electromagnetic engineering and science
Journal Basic Information
Journal DOI :
The Korean Institute of Electromagnetic Engineering and Science
Editor in Chief :
Volume & Issues
Volume 5, Issue 4 - Dec 2005
Volume 5, Issue 3 - Sep 2005
Volume 5, Issue 2 - Jun 2005
Volume 5, Issue 1 - Mar 2005
Selecting the target year
Efficient Performance Enhancement Scheme for Adaptive Antenna Arrays in a Rayleigh Fading and Multicell Environments
Kim Kyung-Seok ; Ahn Bierng-Chearl ; Choi Ik-Gueu ;
Journal of electromagnetic engineering and science, volume 5, issue 2, 2005, Pages 49~60
In this paper, an efficient performance enhancement scheme for an adaptive antenna array under the flat and the frequency-selective Rayleigh fadings is proposed. The proposed signal enhancement scheme is the modified linear signal estimator which combines the rank N approximation by reducing noise eigenvalues(RANE) and Toeplitz matrix approximation(TMA) methods into the linear signal estimator. The proposed performance enhancement scheme is performed by not only reducing the noise component from the signal-plus-noise subspace using RANE but also having the theoretical property of noise-free signal using TMA. Consequently, the key idea of the proposed performance enhancement scheme is to greatly enhance the performance of an adaptive antenna array by removing all undesired noise effects from the post-correlation received signal. The proposed performance enhancement scheme applies at the Wiener maximal ratio combining(MRC) method which has been widely used as the conventional adaptive antenna array. It is shown through several simulation results that the performance of an adaptive antenna array using the proposed signal enhancement scheme is much superior to that of a system using the conventional method under several environments, i.e., a flat Rayleigh fading, a fast frequency-selective Rayleigh fading, a perfect/imperfect power control, a single cell, and a multicell.
A 2.4 GHz 802.11b Throughput Estimation In a Noisy Environment Using an Experimental Noise Parameter
Hur Min-Ho ; Lim Sung-Jin ; Kwon Sewoong ; Yoon Young-Joong ;
Journal of electromagnetic engineering and science, volume 5, issue 2, 2005, Pages 61~65
In this paper, a numerical permissible disturbance model is proposed to preserve a throughput performance of a 2.4 GHz wireless LAN service. The model is composed of two parameters, a peak value and a time rate of noise signal. The model parameters are experimentally determined from an APD parameter measurement. The APD parameter is measured by using the APD measurement method which is recommended from CISPR/A/447/CD.
Complex Antenna Factors of EMI Antenna with Coaxial Cable Balun for Measuring Electromagnetic Fields
Ju Chang-Hyun ; Jun Dae-Hwa ; Kim Ki-Chai ;
Journal of electromagnetic engineering and science, volume 5, issue 2, 2005, Pages 66~71
The purpose of this paper is to present the complex antenna factor of an EMI dipole antenna with a balun consisting of two coaxial feeders(coaxial cable balun) for measuring electromagnetic fields. A new formula of complex antenna factors for an EMI antenna with coaxial cable balun is derived using by power loss concepts. The complex antenna factor shows that the present result in this study was identical with that of the result from S-parameters. The theoretical complex antenna factors derived by power loss concepts are in good agreement with the experiments.
Leaky Dispersion Characteristics in Circular Dielectric Rod Using Davidenko's Method
Kim Ki Young ; Tae Heung-Sik ; Lee Jeong-Hae ;
Journal of electromagnetic engineering and science, volume 5, issue 2, 2005, Pages 72~79
The leaky dispersion characteristics of a circular dielectric rod were investigated using Davidenko's method for several lower-order transverse magnetic(TM) modes. The normalized complex propagation constants were precisely determined and their tolerances below
compared with zero for both real and imaginary parts. It was also checked whether the normalized complex propagation constants obtained represented forward leaky waves. The leaky modes existing below the cutoff frequency of the guided mode were classified as a nonphysical mode, reactive mode, antenna mode, and spectral gap based on a precise determination of the complex propagation constants. Finally, the effects of the dielectric constant and radius of the dielectric rod on the leaky dispersion characteristics were also considered.
A Design of Varactor-Tuned Combline Bandpass Filter Using Coupling Varactor Diode
Kim Byung-Wook ; Back Hyung-Il ; Yun Sang-Won ;
Journal of electromagnetic engineering and science, volume 5, issue 2, 2005, Pages 80~86
In this paper, a novel varactor-tuned combline bandpass filter is presented. The coupling varactor diode between line elements is introduced to control the passband bandwidth so that the passband bandwidth can be maintained almost constant within the tuning range. The equivalent circuit and design equations are derived, and the optimum design is discussed. A 1.7 GHz, two-pole bandpass filter with a bandwidth of
was constructed. The absolute passband bandwidth was maintained almost constant within more than 0.4 octave tuning range.
Analysis of Electromagnetic Wave Scattering from a Sea Surface Using a Monte-Carlo FDTD Technique
Choi Dong-Muk ; Kim Che-Young ; Kim Dong-Il ; Jeon Joong-Sung ;
Journal of electromagnetic engineering and science, volume 5, issue 2, 2005, Pages 87~91
This paper presents a Monte-Carlo FDTD technique to determine the scattered field from a perfectly conducting surface like a sea surface, from which the useful information on the incoherent pattern tendency could be observed. A one-dimensional sea surface used to analysis scattering was generated using the Pierson-Moskowitz model. In order to verify the numerical results by this technique, these results are compared with those of the small perturbation method, which show a good match between them. To investigate the incoherent pattern tendency involved, the dependence of the back scattering coefficients on the different wind speed(U) is discussed for the back scattering case.
Novel Oscillator Incorporating a Compact Microstrip Ring Type Resonant Cell with High Efficiency and Superior Harmonic Characteristics
Hwang Cheol-Gyu ; Myung Noh-Hoon ;
Journal of electromagnetic engineering and science, volume 5, issue 2, 2005, Pages 92~96
This paper presents a novel microwave oscillator incorporating a simple microstrip ring type resonant cell as its terminating resonance component. Reduced chip size, higher dc-ac power efficiency, superior harmonic characteristics can be achieved from the introduction of a compact microstrip ring resonator cell. The oscillator provides a second harmonic suppression of 26.51 dB and the output power of 2.046 dBm at 2.11 GHz.
Measurement of Sonobuoy Transmitting Antenna System for Anti-Submarine Warfare
Min Kyeong-Sik ;
Journal of electromagnetic engineering and science, volume 5, issue 2, 2005, Pages 97~103
This paper describes the measured results of sonobuoy transmitting antenna system for anti-submarine warfare (ASW). Since radiation pattern and power density depend on impedance matching between transmitting RF part and antenna with termination resistance, design of matching circuit is very important for sonobuoy system performance. Matching circuit is designed by Smith chart using control of L and C. In standing wave ratio(SWR) measurement using Network Analyzer, SWR of antenna with matching circuit observed 1.5 below at the assigned VHF band. It shows very excellent performance comparison with conversional product that is used for the same object. The measured vertical and horizontal radiation patterns are also shown the satisfaction of military specifications. A drop out of sonobuoy system on the sea is happened when angle of elevation direction is over 10 degrees, and it is conformed that it takes less than I second return to original signal level. The required electric power density is
in the military specification, and measured electric power density is observed over average
at all frequency bands.