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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal 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 8, Issue 4 - Dec 2008
Volume 8, Issue 3 - Sep 2008
Volume 8, Issue 2 - Jun 2008
Volume 8, Issue 1 - Mar 2008
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M-1-1 Cooperative Protocol Based on OSOC-SS to Improve Bandwidth Utilization in USN
Kong, Hyung-Yun ; Hwang, Yun-Kyeong ;
Journal of electromagnetic engineering and science, volume 8, issue 2, 2008, Pages 41~46
DOI : 10.5515/JKIEES.2008.8.2.041
A bandwidth and power efficient high speed ubiquitous sensor network(USN) for realizing a ubiquitous society is a great challenge for researcher community. In this paper we incorporate a cooperative transmission protocol within a special type of multi-code modulation to meet these requirements. Multi-code(Mc) modulation has been developed for high-speed data transmission over wireless channels. We proposed a new class of orthogonal codes for multi-code modulation which is an orthogonal subset of orthogonal codes(OSOC). Our proposed OSOC structure allows us to use only one relay to cooperate M nodes that effectively reduces the bandwidth and power requirement. This protocol is similar to spread-spectrum(SS) technique that can reduce both broad and narrow band jamming.
Parallel-Branch Spiral Inductors with Enhanced Quality Factor and Resonance Frequency
Bae, Hyun-Cheol ; Oh, Seung-Hyeub ;
Journal of electromagnetic engineering and science, volume 8, issue 2, 2008, Pages 47~51
DOI : 10.5515/JKIEES.2008.8.2.047
In this paper, we present a cost effective parallel-branch spiral inductor with the enhanced quality factor and the resonance frequency. This structure is designed to improve the quality factor, but different from other fully stacked spiral inductors. The parallel-branch effect is increased by overlapping the first metal below the second metal with same direction. Measurement result shows an increased quality factor of 12 % improvement. Also, we show an octagonal parallel-branch inductor which reduces the parasitic capacitances for higher frequency applications.
Linearly Constrained Adaptive Array Processing with Alternate Mainbeam Nulling
Chang, Byong-Kun ; Jeon, Chang-Dae ; Song, Dong-Hyuk ;
Journal of electromagnetic engineering and science, volume 8, issue 2, 2008, Pages 52~58
DOI : 10.5515/JKIEES.2008.8.2.052
This paper concerns with signal cancellation problem in a linearly constrained adaptive array processor in coherent environment. Alternate mainbeam nulling approach was proposed to prevent the signal cancellation phenomenon. The linearly constrained LMS algorithm with a unit gain constraint and that with a null constraint in the direction of the desired signal is alternately implemented to reduce the signal interaction between the desired signal and the interferences, which is the main cause of the signal cancellation. It is shown that the proposed method performs better than a conventional method.
Probability Density Function of Samples` Amplitude of ASSS OFDM Signal
Wang, Lei ; Yoon, Dong-Weon ; Park, Sang-Kyu ;
Journal of electromagnetic engineering and science, volume 8, issue 2, 2008, Pages 59~63
DOI : 10.5515/JKIEES.2008.8.2.059
The adaptive symbol selection scheme(ASSS) is popular in reducing peak to average power ratio(PAPR) for orthogonal frequency division multiplexing(OFDM) signals. The probability density function(pdf) of the samples` amplitudes of the adaptively selected OFDM signal without over-sampling has been considered to be approximately equal to the Rayleigh pdf. In this paper, we derive a more precise pdf which shows the relationship between the probability distribution of the samples` amplitudes and the number of the candidate symbols for ASSS. Using the newly derived pdf in the theoretical analysis, more accurate calculation results can be obtained.
Design of the Pattern Adjustable Base Station Antenna for WCDMA Applications
Lee, Sang-Ho ; Lee, Jung-Nam ; Lee, Don-Shin ; Park, Jong-Kweon ; Kim, Hak-Sun ;
Journal of electromagnetic engineering and science, volume 8, issue 2, 2008, Pages 64~69
DOI : 10.5515/JKIEES.2008.8.2.064
In this paper, we have proposed the pattern adjustable base station antenna for WCDMA applications. The proposed antenna consists of an omni-antenna(sleeve monopole) and two movable reflectors. The two reflectors can be controlled by mechanically and used to adjust the horizontal pattern of the base station antenna. The antenna was designed, fabricated, and measured. The antenna covers the entire WCDMA band for VSWR<1.4. The measured antenna gain is more than 15 dBi over the operating frequency range. By changing the angle (a) and the distance (d) of the antenna, the pattern adjustment of the proposed base station antenna is found to be possible.
A Study on Development of the EM Wave Absorber for ETC System
Park, Soo-Hoon ; Kim, Dong-Il ; Song, Young-Man ; Yoon, Sang-Gil ;
Journal of electromagnetic engineering and science, volume 8, issue 2, 2008, Pages 70~75
DOI : 10.5515/JKIEES.2008.8.2.070
In this paper, the EM wave absorber was designed and fabricated for countermeasure against EMI from a ceiling of a tollgate in ETC system. We fabricated several samples in different composition ratios of MnZn-ferrite, Carbon, and CPE(Chlorinated Polyethylene). Absorption abilities were simulated in accordance with different thicknesses of the prepared absorbers and changed complex relative permittivity and permeability according to composition ratio. The optimized mixing ratio of MnZn-ferrite, Carbon, and CPE was found as 40:15:45 wt.% by experiments and simulation. Then the EM wave absorber was fabricated and tested using the simulated data. As a result, the developed EM wave absorber has the thickness of 3.3 mm and absorption ability was more than 20 dB in the case of normal incidence and more than 11 dB for the incident angle from 15 to 45 degrees at 5.8 GHz. Therefore, it was confirmed that the newly developed absorber can be used for ETC system.
A 9 mW Highly-Digitized 802.15.4 Receiver Using Bandpass ∑Δ ADC and IF Level Detection
Kwon, Yong-Il ; Park, Ta-Joon ; Lee, Hai-Young ;
Journal of electromagnetic engineering and science, volume 8, issue 2, 2008, Pages 76~83
DOI : 10.5515/JKIEES.2008.8.2.076
A low power(9 mW) highly-digitized 2.4 GHz receiver for sensor network applications(IEEE 802.15.4 LR-WPAN) is realized by a
CMOS process. We adopted a novel receiver architecture adding an intermediate frequency (IF) level detection scheme to a low-power complex fifth-order continuous-time(CT) bandpass L:tl modulator in order to digitalize the receiver. By the continuous-time bandpass architecture, the proposed
modulator requires no additional anti-aliasing filter in front of the modulator. Using the IF detector, the achieved dynamic range(DR) of the over-all system is 95 dB at a sampling rate of 64 MHz. This modulator has a bandwidth of 2 MHz centered at 2 MHz. The power consumption of this receiver is 9.0 mW with a 1.8 V power supply.
Empirical Prediction Models of 1-min Rain Rate Distribution for Various Integration Time
Jung, Myoung-Won ; Han, Il-Tak ; Choi, Moon-Young ; Lee, Joo-Hwan ; Pack, Jeong-Ki ;
Journal of electromagnetic engineering and science, volume 8, issue 2, 2008, Pages 84~89
DOI : 10.5515/JKIEES.2008.8.2.084
In a wireless channel above microwave frequency, rain attenuation is very important. In order to predict rain attenuation, 1-min. rain rate distribution is required. This paper discusses appropriate conversion methods to estimate 1-minute rain rate from that of other integration time. Based on the measurement data filed in ITU-R WP3J including ETRI data for 6 consecutive years, distributions of rain rate with 1-, 5-, 10-, 20-, 30-minute integration time were analyzed, both on the global and regional basis, and the parametric relationship between the statistical characteristics of 1-minute and other measurement data were investigated to deduce the conversion methods. It is shown that the global model works good with good accuracy for 5-, 10-, 20-min integration time, and the global model is also applicable globally with good accuracy for 5-, 10-, 20-min integration time. The global conversion model was adopted last year as an ITU-R document for new recommendation. The regional conversion model would also be very useful for locations of similar climatic zone.