• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 1996년도 The Korean Institute of Navigation 1996년도 한·중 국제학술 심포지움 및 추계학술발표회 논문집
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• pp.125-134
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• 1996

A design method of double layered electromagnetic wave absorbers with cross-shaped ferrite prominence in the second layer which has broad band frequency characteristics was proposed. The broad band electromagnetic wave absorber can be designed under some approximations by the theoretical model using the equivalent material constants method for the second layer. Based on the developed model broad band electromagnetic wave absorbers with excellent reflectivity frequency characteristics in the frequency range of 30MHz to 3,990MHz were designed.

• 한국세라믹학회지
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• 제31권1호
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• pp.11-16
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• 1994

The impedance matching solution map is not a sufficient method for designing the broad-band absorber because of its difficulty to get numerical data about practical band-width. Therefore, we develope a new method to design the broad-band absorber. The complex permeability limits, which is necessary for designing the broad-band absorber in C-X band (4 GHz~12.4 GHz) were investigated and application was also examined. The complex permeability limits represent the frequency dependence of the complex permeability at a practical frequency band. These complex permeability limits can be used effectively to design broad-band single-layered absorber because they offer numerical data about the band-width in the case of various dielectric loss tangent, practical frequency bands and permitted reflection losses of an absorber.

• Current Optics and Photonics
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• 제2권6호
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• pp.629-634
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• 2018

A broad dual-band terahertz metamaterial filter with sharp out-of-band rejections is designed and demonstrated. The center frequencies of the first and the second bands occur at 0.35 THz and 0.96 THz with 3 dB relative bandwidth of 31% and 17%, respectively. Results are measured using a THz time-domain spectroscopy system that shows agreement with simulations. Physical mechanisms of the broad dual-band resonance are clarified based on transmissions of different structures and surface current density distributions. Influence of structure parameters on the transmission characteristics are discussed. Symmetry of the structure ensures the filter polarization independence at normal incidence. These results supported by the design of the filter could find applications in broad multi-band sensors, terahertz communication systems, and other emerging terahertz technologies.

• ETRI Journal
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• 제28권1호
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• pp.119-122
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• 2006

We present an intelligent optical switching structure based on our lambda-group model along with a working scheme that can provide a distinctive approach for dividing complicated traffic into specific tunnels for better optical performance and grooming efficiency. Both the results and figures from our experiments show that the particular channel partition not only helps in reducing ports significantly, but also improves the average signal-to-noise ratio of the wavelength channel and the blocking performance for dynamic connection requests.

• 전자공학회논문지D
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• 제35D권5호
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• pp.11-17
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• 1998

In this paper, the synthesis procedufe of impedance matching network is presented for broad-band microwave amplifier design, whereby amplifier operating in the octave bandwidth is designed and fabricated in detail. The transfer function of the matching netowrks is synthesized by chebyshev approximation and element values for the networks of specified topology are calculatd for various MILs and ripples. After the transistor is modeled by negative-image device model, the synthesis procedure for matching networks is applied to broad-band amplifier design which has electrical performance of about 12dB gain in 4 to 8GHz range. Experimental results obtained from the fabricated amplifier are shown to approach the electrical performance designed in the given frequency range. Construction of the impedance matching networks by transfer function synthesis is very useful method for the design of broad-band microwave amplifiers.

• 한국ITS학회:학술대회논문집
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• 한국ITS학회 2008년도 제7회 추계학술대회 및 정기총회
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• pp.342-346
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• 2008

• 한국전자파학회논문지
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• 제26권8호
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• pp.718-729
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• 2015

S-대역과 X-대역에서 동작하며, 개구면 공유 구조를 가지는 광대역 패치 안테나를 제작하였다. S-대역 안테나는 $2{\times}2$로 천공된 패치를 가지며, 천공된 자리에 X-대역에서 동작하는 패치 안테나를 $2{\times}2$ 배열하였다. 두 대역에서 모두 20 % 이상의 넓은 대역폭 특성을 가지는 개구면 공유 구조를 가지는 이중 대역 안테나를 제작하고, 방사 특성을 분석하였다.

• 한국정보통신학회논문지
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• 제10권8호
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• pp.1352-1358
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• 2006

이 논문은 듀얼 반사판을 이용한 광대역 보우타이 슬롯 안테나를 제작 실험 했다. 슬롯 안테나는 넓은 도체판에 약 1/2 길이의 가늘고 긴 슬롯을 뚫게 되면 반파장 다이폴과 마찬가지로 효율이 좋고 강한 전파가 복사된다[1] 이 논문에서는 보통 사각 슬롯 보다 대역폭이 넓은 보우타이 형태의 슬롯으로 제작하였다. 먼저 단일 반사판 슬롯 안테나를 제작 실험 측정하였으며 제작된 단일 반사판 슬롯 안테나에 또 하나의 반사판을 슬롯 안테나와 반사판 사이에 삽입함으로서 대역폭을 확장하였다. 제작 실험 결과 VSWR<2.0 이하인 Low Band 대역폭은 약 $22%(793MHz\sim992MHz)$ 대역폭을 가졌으며 High Band 대역폭은 약 $61%(1626MHz\sim3064MHz)$의 대역폭을 가짐을 실험을 통해 알 수 있었다.

• 전기학회논문지
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• 제60권12호
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• pp.2286-2292
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• 2011

In this paper we present the design of Low Noise Amplifier(LNA), mixer and filter for RF front-end part of partial discharge monitoring system. The monitoring system of partial discharge in high voltage power machinery is used to prevent many kinds of industrial accidents, and is usually composed of three parts - sensor, RF front-end and digital microcontroller unit. In our study, LNA, mixer and filter are key components of the RF front-end. The LNA consists of common gate and common source-cascaded structure and uses the resistive feedback for broad band matching. A coupled line structure is utilized to implement the filter, of which size is reduced by the meander structure. The mixer is designed using dual gate structure for high isolation between RF and local oscillator signal.

• 한국항해학회지
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• 제10권1호
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• pp.29-40
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• 1986

Abroad-band design method of a lumped-element 3 dB quadrature hybrid without magnetic coupling is proposed and discussed, where techniques of cascading fundamental hybrids via second-order delay equializers and adding matching sections are adopted. It is shown that the designed broad-band lumped-element 3 dB quadrature hybrid can be easily constructed and its bandwidth reaches up to 54%. Furthermore, the experiments have been carried out, the results of which agree with the theoretical ones, and hence, the validity of the broad-band design method proposed here was confirmed.