• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.6 s.109
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• pp.529-537
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• 2006

Multi-layer PCBs are of ien used In compact microwave circuit design as density of PCB layout is increased. In this paper, the crosstalk between coupled lines connected with vias in a 4-layer PCB is investigated theoretically based on the circiuit-concept approach. Coupled lines connected with vias in a 4-layer PCB are divided into three sections, which are coupled microstrip lines and upper via section, center via section, and lower via and coupled microstrip lines section, respectively. Each section is represented by ABCD matrix. By cascading these three ABCD matrices crosstalk between coupled lines connected with vias in a 4-layer PCB is approximately calculated. The validity of this theoretical approach is verified by comparing the calculated results with the simulated ones using HFSS.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12B
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• pp.1724-1732
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• 2001

In this paper, a technique for increasing the bandwidth of microstrip array antennas using the parallel coupled lines on a single layer is presented. Four types of wideband microstrip array antenna are designed and the characteristics of each type are analyzed. In addition, an iterative method using a distributed network is proposed to design the parallel coupled lines as a wideband impedance matching network. Measurements show that the proposed antennas provide wider bandwidths ∼1.7 times those of conventional microstirp array antennas, while the sizes of proposed antennal are the same as that of a conventional array. And low cross-polarization level can be obtained through symmetrical locations of the parallel coupled lines section

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.6 s.121
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• pp.680-688
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• 2007

Time domain closed-form analytical solutions to the coupled telegrapher's equations for the voltage and current on a lossless multiconductor transmission line are presented. The resulting expressions are obtained in the form of exact time domain propagators operating on the line voltage and current. Time domain numerical methods are developed and examples showing exceptionally accurate results are obtained for uniform and nonuniform; symmetric and asymmetric strip lines.

• Electronics and Telecommunications Trends
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• v.19 no.1 s.85
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• pp.109-115
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• 2004

최근 들어 통신시장이 성숙단계에 도달하여 성장이 한계를 보임에 따라 선진 각국의 통신사업자들은 유무선 결합서비스 제공을 통해 새로운 돌파구를 찾고자 노력하고 있다. 본 고에서는 이러한 유무선 결합서비스와 관련된 최근동향을 위주로 하여 미국내 3개 장거리통신사업자 및 4개 지역통신사업자(RBOC)의 유무선 결합서비스 제공현황을 분석하고, 미국 정부의 결합서비스에 대한 규제정책을 살펴본 다음 결론으로서 시사점을 제시하였다.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.206-207
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• 2003

광집적회로의 등장으로 그 설계에 있어서 다양한 구조의 광배선은 필수적 요소가 되었다. 일반적으로 전기적 배선 및 소자간에 전자기파의 간섭으로 인해 신호의 왜곡이 야기될 뿐 아니라 기생정전효과 등에 의해 소자 시간지연이 유발되듯이, 광 집적회로에서도 광배선간 감쇄필드의 겹침으로 인해 원하지 않는 광결합이 발생하게 된다. 이러한 광집적회로내에서의 이러한 불필요한 광결합을 줄이기 위해서 곡선형 구조의 광배선들이 이용되며 대부분의 경우 이러한 곡선형 도파로 부분의 광결합은 무시된다. (중략)

• Proceedings of the KAIS Fall Conference
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• 2002.11a
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• pp.225-228
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• 2002

현대 산업이 점차 세분화되고 산업용 반응조, 수조, 송수관 등 시설물이 증가하고 시설물의 관리가 증가함에 따라 본 논문에서는 감마선을 이용한 결합 검출기를 개발하였다. 물질의 투과성이 좋은 감마선의 특성을 이용하여 물체의 결합을 측정을 한다. 감마선이 물체를 투과하여 수집된 데이터를 영상 신호처리를 하여 이미지로 나타냄으로서 측정을 하는 사용자가 물체의 결합의 위치를 쉽게 알 수 있도록 하였으며 측정기기를 소형화하여 이동을 편리하게 하는데 본 논문은 목적을 두고 하드웨어를 제작하였으며, 물체내부의 결함은 영상 신호처리의 시뮬레이션을 통해서 확인하였다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.10 s.113
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• pp.935-942
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• 2006

In this paper, a novel theory of realizing the series capacitor with broadside coupled suspended substrate stripline (BCSSS) is proposed. The proposed theory is relatively simple because the method of odd mode analysis is only applied: However, this theory supplies reliable result by considering the line effective width and end effect caused by the fringing field. The simulation results are presented to compare and analyze the characteristics of the ideal lumped capacitor and the coupled line capacitor. Also, the capacitive gap coupled line band-pass filter based on the proposed theory are designed and fabricated. The results prove successfully the validity of the proposed theory.

• Journal of the Korean Magnetics Society
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• v.15 no.6
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• pp.299-302
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• 2005

We investigated the structural md magnetic properties of Fe-Pt nanowires with linear and zigzag structures by using first-principle calculational methods. Structural degrees of freedom are optimized, the bond lengths and bond angles are determined, magnetic moments, spin density, and density of states are calculated. Results show that the zigzag structure is more stable than the linear one, and has a longer bond length and smaller magnetic moments for both Fe and Pt atoms.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.5
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• pp.510-515
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• 2011

In this paper, an artificial transmission line coupler with slotted-triangular patches, which is compact and spacesaving structure, is proposed. The proposed structure has specific features of not only convenience for adjusting the characteristic impedance and the phase of its coupled line by varying the lengths of the slots of the artificial transmission lines in designing a coupler but also the maximized coupling value at less than ${\lambda}$/4 electrical length so that it can be designed in compact and small dimensions, while conventional coupled line couplers are generally limited in compact and miniaturized designs by their ${\lambda}$/4 transmission lines. A fabricated 15 dB test-coupler at 2.4 GHz band by proposed design method shows good agreement with theory and simulation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.10
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• pp.1145-1150
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• 2012

In this paper, an improved Schiffman phase shifter is proposed using slot-coupled lines. It consists of the typical coupled lines and a simple rectangular slot which is placed in the ground plane underneath the coupled lines. Phase responses of the slot-coupled Schiffman phase shifter are analyzed in consideration of the phase velocity of two independent transmission modes and the characteristic impedance of slot-coupled line. The $905^{\circ}$ Schiffman phase shifters with high impedance ratio is realized at 2.4 GHz, which cannot be implemented with the conventional coupled lines. The measured results show that the bandwidth is around 74.2 % within the phase errors ${\pm}5^{\circ}$. The measured return loss is found to be better than 15.0 dB and insertion loss is less than 1.5 dB over the operating frequency band.