• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.12
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• pp.43-49
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• 2004

In this paper, we have designed a mode size converter to reduce coupling loss between super-high delta silica optical waveguides and single mode fibers. The new mode size converter has three design aspects; periodically segmented taper waveguide for minimal size, lateral taper waveguide for simple fabrication, and surrounding trenches to improve coupling loss. In the optimal mode size converter design, coupling loss is 0.33dB/point without trenches and 0.2dB/point with trenches.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.7
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• pp.1770-1776
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• 1998

This paper presents a waveguide-to-mircostrip transition at Ka-band using antipodal finlines. Critical design parameters were identified with the help of theoretical analysis. Experimental optimization was performed together with 3-D FEM analysis in an effort to find optimum dimensions of the transition. In addition to the conventional antipodal finline transition, a new dielectric impedance transformer was introduced to further reduce the insertion loss. Optimized waveguide-to-microstrip transition showed an insertion loss of 0.3~0.4dB/transition at Ka-band. This transition provides superior reproducibility and better performance than conventional coaxcable-to-microstrip transition.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.4
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• pp.487-493
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• 2001

In this paper, A new microstrip bandpass filter is proposed. The novelty of the proposed structures is to use a interdigital capacitor and embeded slot that are fanned on a patch resonator such that its insertion loss and size can be significantly reduced simultaneously. As a result, it is found that the resonant frequency of patch filter designed at 5 GHz is decreased to 1.8946 GHz and the insertion loss is reduced from -2.168 dB to -0.379 dB. This proposed filter has small size and low insertion loss in comparison with the conventional parallel edge coupled bandpass filter.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.2
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• pp.173-181
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• 2011

In this paper, we propose a half mode substrate integrated waveguide(HMSIW) balanced bandpass filter to yield improved isolation between output ports. In order to achieve good isolation, resistive coupling slot is employed in HMSIW filter. The measurement results show that the insertion losses($S_{21}$, $S_{31}$) are $5.4{\pm}0.2$ dB and input return loss($S_{11}$) is more than 10 dB from 5.8 GHz to 6.4 GHz. Moreover isolation between output ports is larger than 18 dB and phase difference of output ports is $180{\pm}10^{\circ}$.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.35T no.3
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• pp.31-36
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• 1998

In this paper, Image Rejection Interdigital Filter(IRIF) for 5.8GHz wireless LAN was designed and implemented. When the input signal is -30dBm in the 4~8㎓ frequency band, the insertion loss including all kinds of loss is 6.3dB in the center frequency 5.775GHz. Therefore, it was showed practically insertion loss of about -3.3dB. Especially, image signal rejection is about -l7dB in the image frequency 6.475GHz. and skirt characteristics of the high frequency band is very excellent. Therefore, it was confirmed that the proposed IRIF is suitable for RF image signal rejection in the 5.8GHz wireless LAN system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.123-124
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• 2009

현재 전자기기의 소형화 추세에 맞물려 수동 소자중의 하나인 트랜스포머의 소형화가 큰 이슈가 되고 있다. 본 논문에서는 실리콘 웨이퍼 위에 트랜스포머와의 절연층을 삽입 하여 기판의 에디 커런트로 오는 멤돌이 손실의 영향을 줄이고 중간 코어를 투자율이 높은 퍼멀로이로 설계하여 1차 코일과 2차 코일의 턴수의 비를 기준으로 1:1 인 트랜스포머 (3/3, 5/5, 7/7)의 인덕턴스 및 상호 인덕턴스를 시뮬레이션 하였다. 트랜스포머의 최대 크기는 $1mm\;{\times}\;1.95mm$이고 선폭과 선간 간격, post의 높이는 각각 50um 이다. 이때 삽입 손실은 10GHz에서 0.12dB의 낮은 손실 값을 나타내었다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.152-157
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• 2008

Enclosure is widely used for the sound insulation in a ship. But it is very difficult to estimate the sound insertion loss for the enclosure because the sound field between the enclosure and the machine is so complex. Therefore, it is usually estimated experimentally. In this research, sound insertion loss of the enclosure is estimated by theory assuming that the sound field in the enclosure is reverberation field. And the results from the theory are compared to those from the experiment.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10c
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• pp.544-547
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• 2006

본 논문에서는 디지털콘텐츠 식별자 연계 표준인 UCI 정보를 이용하여 효율적인 디지털 콘텐츠의 관리가 가능한 무손실 비디오 워터마킹 기법을 이용하였다. 제안한 기법은 각 비디오 프레임의 히스토그램의 특정 구간의 화소값을 수정함으로써 워터마크를 삽입한다. 4CIF 크기의 테스트 시퀀스를 통한 실험결과 화질의 열화가 적으면서도 UCI 정보를 100% 왜곡없이 검출이 가능하였으며, 원본 디지털 비디오 콘텐츠도 모든 테스트 시퀀스에서 100% 복원이 가능하였다. 제안한 기법은 디지털 비디오에 UCI 정보를 직접 삽입하여 메타데이터가 없을 경우 콘텐츠만으로도 콘텐츠의 식별이 가능하고 콘텐츠로부터 추출한 UCI 정보를 통하여 효율적인 관리가 가능하면서 유사시 원본 콘텐츠를 손실없이 복원이 가능할 수 있어 영화, 방송 등의 다양한 비디오 콘텐츠의 관리를 위해 응용될 수 있다.

• The Journal of the Acoustical Society of Korea
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• v.17 no.1
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• pp.17-23
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• 1998

본 논문은 높은 전기 역학적 결합 계수를 갖고 있는 64°LiNbO3기판에 leaky표면 탄성파를 이용하여 종 결합 형태의 대역이 넓고, 손실이 적은 필터의 제작을 위한 연구이다. 이 기판 위에 1차 모드와 2차 모드를 이용하고 입력 IDT와 출력IDT사이의 거리, 그리고 전 극의 두께 및 전극 개수를 적절하게 조절하므로서 통과 대역 폭이 15MHz이상, 삽입 손실 1.28dB 및 저지대역 50dB인 특성을 얻을 수 있었다. 아울러, 전극의 두께는 파장과의 비를 고려해 2500Å으로 할 때 최적의 결과를 얻을 수 있었으며, IDT와 IDT 사이의 거리는 0.25 λ, IDT와 반사기 사이의 거리는 0.46λ로 할 때 가장 이상적인 결과를 얻을 수 있었다. 제 작한 필터는 329.3MHz의 중심 주파수를 갖고 있는 소자로서 소형이고 낮은 삽입 손실을 갖 고 있으며, 무선 호출기에 사용 가능하다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.324-329
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• 2018

This study examined the effects of the contact position and structure of the test probe on its signal transmission characteristics. The contact position in the operating of the test probe was considered and then divided into the plunger inner contact and barrel inlet contact. The high frequency performance of the test probes was investigated for both contact positions. The signal transmission characteristics of the test probes with the structures of double, single, and out-spring was also analyzed. The insertion and return losses were calculated using the HFSS and the characteristic impedance of the test probes was analyzed using a Q3D simulation. The insertion loss of the barrel inlet contact was smaller than that of the plunger inner contact. The contact position of the test probe may result in a change in the high frequency performance. The out-spring probe has better frequency characteristics at -1 dB insertion loss and -10 dB return loss. The double probe and single probe have the same characteristic impedance with $30.8{\Omega}$. On the other hand, the out-spring probe has an impedance of $47.1{\Omega}$. The out-spring probe is closer to $50{\Omega}$ than the other probes and then shows higher signal transmission characteristics. The out-spring probe has superior high-frequency characteristics and is expected to be suitable for high-speed applications.