• KIEE International Transactions on Electrophysics and Applications
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• 제5C권2호
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• pp.81-85
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• 2005

This paper presents some interesting results regarding the harmonic performance on the photonic band-gap (PBG) structures formed by periodic conducting vias. Study on PBG structures has been one of the major topics in electromagnetics, microelectronics, and communications areas. In most of the studies, the band-gap filtering behavior was fulfilled by a periodic pattern of perforations on the ground planes of microstrip lines. Nevertheless, the PBG characteristics can also be realized using a periodic via-pattern along the transmission-line circuits. Hence, some of the via-typed PBG structures are studied and their frequency characteristics in terms of the scattering parameters are presented. It is found that by varying the length of vias with respect to the period pattern, different harmonic performances are observed.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2002년도 종합학술발표회 논문집 Vol.12 No.1
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• pp.423-433
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• 2002

A very fast method of moments(MoM) for the analysis of microstrip structure is considered based upon the use of rooftop basis and razor test functions in conjunction with a new closed-form Green's functions. The present method presents a robust approach to obtain the Green's functions which can be derived by use of only one set of approximation parameters independently of operating frequency range. Moreover, using the present MoM scheme, the MoM matrix elements can be analytically evaluated with few number of terms in comparison with the previous method. So, the computational efficiency can be improved significantly without loss of the precision. In order to check the validity of the present method, performance is demonstrated for the example of a coaxially-fed microstrip transmission line and the present results are compared with the previous results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1455-1457
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• 2002

The real-time dynamic rating system(DRS) can provide the maximum ampacity within required periods, so it can help the transmission-line operation more safely and efficiently. Because the conductor temperature is the main limit of increasing rating current, conductor temperature monitoring(CTM) technology is the basic to DRS. In this paper, real-time CTM was developed for 345kV XLPE cable in tunnel and we have also compared the CTM result of this study with the result according to IEC 287 and JCS 168 thermal parameters.

• 전자공학회논문지A
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• 제30A권11호
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• pp.29-39
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• 1993

For an economical or timely reason, the types of subscriber loops for ISDN basic rate access service will, at least initially, be that of the pre-existing telephone network, that is, 2-wire twisted-pair metallic cable. Therefore, it is important to assess the high-speed digital transmission capability of the 2-wire subscriber loops. In this paper, the impairments such as intersymbol interference, crosstalk, and impulse niose are modeled. And then, symbol error probabilities in terms of SNR in DSL system using ECH and 2B1Q line code are analytically derived and numerically calculated. Also, the relationship between the quality of service required in ISDN subscriber section and the loop parameters is investigated.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2002년도 춘계종합학술대회
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• pp.288-292
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• 2002

RF 회로에 적합한 새로운 형태의 on-chip ESD protection 방법을 제시하였다. RF 회로의 특성을 이용하여 DC blocking capacitor 앞에 short-circuited stub를 달아서 ESD 소자로 활용하였다. 특히 short-circuited stub를 매칭 회로의 일부로 사용하여 stub의 길이를 줄일 수 있다. 또한 short-circuited stub의 width와 metal의 성분으로 ESD threshold voltage를 쉽게 예측 가능하다. 기존의 ESD 방지 회로와 달리 RF 회로를 위한 ESD 방지 회로에서 문제시되던 기생 capacitance 성분에 대한 문제점을 해결 할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2464-2466
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• 1998

A switch is a component with two or more ports that selectively transmits, redirects, or blocks optical power in a fiber transmission line. Our switch uses rotation mechanism using stepping motor, hence the common optical fiber can scan and allign to one of the arrayed N optical fibers to provide optical path by electronic precise control. The developed switch is consisted of switching module and its control module. The performance parameters of a switching loss and a repeatability are considered very important. We performed the study to reduce the switching loss and improve the repeatability of switch. The switch can be widely used as a test instrument of optical device and of optical cable in factory, also of optical cable monitoring systems.

• Journal of electromagnetic engineering and science
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• 제15권1호
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• pp.31-36
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• 2015

The design of a new compact band-pass filter is proposed, which is based on the microstrip composite right- and left-handed transmission- line (CRLH-TL) structure. Particularly, the interdigital coupled (IDC) lines of the CRLH geometry are proposed to be parted by inserting open stubs to meet the specifications on the passband. In addition, there is another pair of stubs to complete the design in a limited space. These are considered in the TL-based analysis and the design parameters are calculated by genetic algorithm optimization. The measurement is shown to be acceptable and agreeable with the circuit and electromagnetic field simulations. In addition, the zerothorder resonance (ZOR) phenomenon is verified.

• Journal of electromagnetic engineering and science
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• 제18권2호
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• pp.73-77
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• 2018

This paper proposes a dual-band bandpass filter using stepped-impedance resonators (SIRs) with parallel coupled structures. The proposed filter adopts U-shaped SIRs with parallel coupled lines (PCLs) that have interdigital and comb-line shorted ends. The central PCLs build an upper passband and a transmission zero, and the two U-shaped SIRs build a lower passband. Four resonators and coupling structures are theoretically analyzed to derive its scattering parameters. A novel dual-band bandpass filter is designed and fabricated using the induced scattering characteristics. The measured results show that the fabricated dual-band bandpass filter has an insertion loss of less than 1.02 dB in the lower band of 2.45 GHz and of 3.01 dB in the upper band of 3.42 GHz, and a band-to-band isolation of more than 40 dB, from 3.14 to 3.2 GHz.

• 대한전기학회논문지:전력기술부문A
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• 제53권8호
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• pp.446-453
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• 2004

This paper focuses on the evaluation of FACTS control on available transfer capability(ATC) enhancement. Technical merit of FACTS technology on ATC boosting are analyzed. More effective control means for line flow and bus voltage are required for appling FACTS. In this paper, the power flow calculation method for deriving FACTS control parameters based on current injection model(CIM) and newton method. Integrated scheme for ATC calculation considering dynamic characteristic of power system is suggested. Study is based on the IEEE 57-bus system demonstrate the effectiveness of FACTS control on ATC enhancement.

• 조명전기설비학회논문지
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• 제15권3호
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• pp.83-90
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• 2001

본 논문은 전력계통에 저주파수 동요현상을 제거하기 위한 목적으로 쓰이고 있는 전력계통 안정화 장치의 적정 파라메타 선정에 관한 알고리즘을 다루었다. 실측에 의한 발전기 시스템의 모델로부터 시스템 제 정수를 구하고, 극좌표 이동법으로 적절한 전력계통 안정화 장치의 파라메타를 Matlab으로 작성하여 구했다. 이 기법으로 선정된 전력계통 안정화 장치의 파라메타로 1기 무한대 계통에 적용한 시뮬레이션 결과는 만족한 만큼의 댐핑 효과를 보았다.