• Journal of electromagnetic engineering and science
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• 제5권1호
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• pp.14-20
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• 2005

In this paper, a technique is presented for broadbanding the bow-tie slot antenna fed by a CPW(coplanar waveguide). The bandwidth performance of existing bow-tie slot designs is greatly enhanced by optimizing the slot shape and properly adjusting the characteristic impedance of the coplanar waveguide feeding the slot. To connect the 50-ohm input coaxial line to the CPW feed line, a linear taper in the CPW is employed. The designed antenna shows a 3.5 $\~$ 10.0 GHz impedance bandwidth, a 3.5 $\~$ 6.0 GHz pattern bandwidth, and a 5.5 $\~$ 7.5 dBi gain over 3.5 $\~$ 6.0 GHz. Above 6.0 GHz, the antenna radiation pattern appreciably deviates from the typical dipolar pattern.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 D
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• pp.2009-2010
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• 2006

This paper presents an adaptive line coupler to match input impedance of the Power line Communication(PLC) modem between access impedance of the power line. This line coupler provides maximum signal power transmiting capability, high reliability. The structure of this coupler is simple and designed to make a easy and low cost. The proposed line coupler is suitable for Amplitude Shift Keying(ASK) or Phase Shift Keying(PSK) modem. To figure out our models, the analysis of the transmitting features of power line channel is performed in the time domain at the carrier frequency. As a result of this study, we present the values of capacitors in the capacitor bank and adaptive line coupler circuit.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 춘계학술대회
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• pp.329-332
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• 2011

최근 사용하는 정보량의 증가로 인해 디지털 회로가 점점 고속, 소형 집적화를 요구로 인해 인쇄회로 기판 역시 높은 신뢰성과 소형화가 요구되어 지고 있다. 특히 POWER PLAN / GROUND PLAN 간 임피던스 영향, 주파수 영향을 고려하여 GROUND / POWER VIA를 통해 개선하고 있으나 너무 많은 VIA가 사용되어 PCB 제조업체 입장에서는 단가 상승 및 납기 지연, 불량요인이 지속적으로 증가하고 있다. 하여 본 논문에서는 VIA 개체수 최적화를 검증 하기 위하여 정형화된 PCB구조의 기본 Design을 활용하여 POWER PLAN과 GROUND PLAN 사이에 VIA의 특정 개수에서 IMPEDANCE값이 수렴하는 것을 검증하여 최적화된 VIA개수를 찾아 보았다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.652-655
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• 2003

In this paper, step-down piezoelectric transformer is studied. The piezoelectric transformer, made of lead zirconate titanate solid solution ceramic, is operated by a fundamental contour-extensional vibration mode. The transformer of 14mm length, 14mm width and 4.5mm thickness was made up two shape(Type I and II). The resonant frequency (fr) is 144kHz and 128kHz at the load resistant of $7.5{\Omega}$ that is a similar to calculating matching impedance. The gain (G) obtained 0.19 and 0.08 at each resonant frequency, when applied input voltage is 25V. The temperature difference with the variation of load resistant was increased with increasing load resistant and was the lowest at $7.5{\Omega}$ near the matching of output impedance.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2002년도 종합학술발표회 논문집 Vol.12 No.1
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• pp.290-292
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• 2002

In this paper, we present a simple design method and measurement results for circular loop antenna arrays, which can be used for LS band operation, such as access point antennas in the wireless LAN system. It has been shown that the input impedance of a circular loop can be adjusted near 100 $\Omega$ using a short stub. The length of the stub can be immediately determined in the work place through the measurement of S11 with a network analyzer. Fabricated arrays show high antenna gains as much as 12.4㏈i and 15.1 ㏈i at the center frequency of 2.45 ㎓ for 4${\times}$l and 4${\times}$2 array, respectively. These types of loop arrays can be fabricated at a low cost.

• 한국정밀공학회지
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• 제23권4호
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• pp.60-66
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• 2006

For the purpose of finding out the sound field characteristics in a rectangular cavity, analytical and experimental studies are performed with white noise input. Two-microphone impedance tube method is used to measure the impedances of foamed aluminum. Foamed aluminum is well known metallic porous material which has excellent properties of light weight and high absorbing performance. And predicted impedances of foamed aluminum are compared with measured impedances. The predicted acoustical parameters are applied to the theoretical analysis to predict sound pressure field in the cavity. The measured sound absorption effects are compared with the predicted values for both cases with and without foamed aluminum lining in the cavity of the rectangular enclosure.

• 한국통신학회논문지
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• 제26권12B호
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• pp.1754-1757
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• 2001

본 논문에서는 IMT-2000, 무선LAN, PCS 대역인 R-band에서 Coplanar waveguide (CPW)와 Photonic Bandgap (PBG)을 이용한 증폭기를 설계 및 제작하였다. 기존 마이크로스트립을 이용한 증폭기에만 적용되던 PBG 기술을 처음으로 CPW를 이용한 증폭기에 적용하여 출력효율 및 IMD를 측정하였다. PBG구조는 매칭 네트웍구성을 위해 최적화되었으며 이로인해 입출력 반사손실이 최소화 되도록 PBG 구조가 정합되었다. 측정결과 CPW구조에 새롭게 적용퇸 PBG구조를 이용하여 동일 IMD에 대해 15%의 출력효율과 동일 출력에 대해 IMD 4.5dB 향상을 얻을 수 있었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.318-318
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• 2000

Current signal square based on switch current is presented in this article. This is the new technique that can design current signal square circuit by using switch-current memory cell, current square and sample and hold technique, which have been presented by the general switch-current. This principle which is present have the good electrical characteristics such as the low input impedance, high output impedance and high frequency response. The system can also operate in the audio frequency range to the high frequency current signal. The system application of this technique can be apply to the current signal multiplier by quarter square technique. The experimental results agree well with the theory as high accuracy and linearity.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1995년도 춘계학술대회
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• pp.68-70
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• 1995

A low-noise pre-amplifier is developed for use in Topographic Brain Mapping system. It consists of signal generator, signal amplifier with a impedance converter, shield driver, body driver, differential amplifier, and isolation amplifier. Pre-amplifier circuit is designed with the concept of isolation and active body and shield driver. This amplifier shows the good noise behavior, high CMRR, high input impedance, low leakage current and high IMRR.

• 대한전자공학회논문지
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• 제8권5호
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• pp.1-9
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• 1971

양산화를 전제로한 계수형계측기로서 4자리표시, 정도 ±0.1% 진치 ±1 digit 이내, 입력 impedance 1000MΩ 이상(1.500V 범위), 측정범위 1mV∼1,000V 4단절환, 자동영점교정으로 저항 및 직류전류 측정기능도 갖춘 Digital Voltmeter를 목표로 이에 적합한 A/D 변환기를 추구하였다. 이 결과 A/D 변환기에서 일어나는 적분 slope의 직선성에 미치는 요인을 해석하여 매우 간단한 회로구성으로도 효과적인 성능을 보장 할 수 있음을 확인하였다.