• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.4
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• pp.825-834
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• 2000

In this paper, we have designed a bandpass filter with via-holes ground on K-band To pass only the 25 ~30% of the bandwidth at the center frequency of 19.6GHz, we have designed a six-order interdigital bandpass filter using microstrip lines. Simulation results of optimization according to via-holes size and numbers of interdigit bandpass filter shows a excellent agreement with theoretical values on passband frequency. Experimental results of BP filters show that mesaured center frequency is 19.150Hz, insertion loss, -4.1dB, reflection coefficient, -16.7dB. It proved that the vis-holes ground size and numbers must be considered to design the bandpass filter.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.9
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• pp.888-895
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• 2004

This paper proposes new miniaturization method of parallel coupled line filter by using capacitors and grounding. Proposed method can reduce resonator size by using only a small number of capacitor and grounding of parallel coupled line filter which is conventional in field of RF filters because of its design and fabrication simplicity. This paper applies the miniaturization method of transmission line and parallel coupled line to parallel coupled line filter, and presents that grounding can reduce the number of shut capacitors. Presented miniaturized method has merits of miniaturization of parallel coupled line, harmonic suppression, and improvement of high frequency skirt with harmonic suppression. For verification of proposed method, this paper presents a hairpin filter, which has 900 MHz center frequency and 10 % FBW, miniaturized to λ/4 by proposed method.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.10
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• pp.2233-2238
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• 2013

A novel design method of ultra wideband based on the composite right-/left handed (CRLH) transmission line is presented in this paper. Defected ground structure and microstrip interdigital coupler are used to implement the CRLH transmission line. The proposed CRLH transmission line in this paper have composite characteristics of low pass filter and high pass filter, also it has good advantages of low insertion loss and ultra wide passband characteristics. The structure with different cell number are studied, and the UWB filter using 3-cell CRLH transmission line is fabricated and measured, which shows a good agreement between simulated and measured results. It has center frequency of 5 GHz, fractional bandwidth of 105 %, and insertion loss of 0.7 dB at center frequency.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.6
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• pp.43-48
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• 2001

This paper represents the design of the ground resistance measuring system insensitive to the noise in the earth. Generally, conventional ground resistance measuring instruments may fail to give a precise values for ground resistance under the situations where there is a high ground potential produced by unbalanced power system currents, haromonic currents and noise etc. To make up the defect of conventional ground resistance measuring instruments, in this paper the ground resistance measuring system using high-performance L-C resonant filter and digital signal processor is designed and the insentivity of the designed ground resistance measuring system for noise in the earth is verified by field test on power service and off power service.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.11
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• pp.1248-1253
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• 2008

The MCS(Micro-Coplanar Strip) line with ground has been analyzed. The conformal mapping method is used to calculate the quasi-static effective dielectric constant and characteristic impedance of this MCS line. The computed results of the present work are found to be in good agreement when compared with the results obtained using commercial S/W, IE3D. And in this paper, the stepped-impedance low pass filter is designed and fabricated with MCS lines for improving the frequency responses. The LPF proposed structure has been also designed and implemented to have the sharp attenuation characteristics in stop band. The agreement between simulation and measurement results verify the implemented LPF.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.11
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• pp.36-40
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• 2013

A novel design method of ultra wideband bandpass filter using CRLH transmission line with Dumbell type DGS is presented in this paper. Defected Ground Structure and microstrip interdigital capacitor are used to design the ultra wideband (UWB) filter. CRLH transmission line has composite characteristics of low pass and high pass filter. As control of cutoff frequency of low pass and high pass response on CRLH transmission line, we can get characteristic of UWB filter. We designed and simulated for CRLH transmission lines with one, two, four, and eight cells. A UWB filter using four cells CRLH is designed and fabricated to verify the results. The characteristics of designed filter have center frequency of 5GHz and relative bandwidth of 88%.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2011.10a
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• pp.67-67
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• 2011

본 논문에서는 접지시스템의 성능을 평가하기 위한 광대역 접지임피던스 분석기에 대하여 기술하였다. 시제작 측정기는 65 Hz~1.28 MHz의 신호발생부와 이득 20 dB, 출력 임피던스가 $0.1{\Omega}$인 전류 증폭부, 전압 및 전류 측정부, 신호처리부, 표시부로 구성된다. 또한, 외부 노이즈로 인한 측정의 오차를 줄이기 위하여 디지털 대역통과 필터를 적용하였다.

• The Journal of the Acoustical Society of Korea
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• v.31 no.5
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• pp.309-316
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• 2012

This paper suggest configuration method of small-size system and design method of module using multi power. In particular module designed to focus on PDN(Power Distribution Network) and filter configuration method to improve the characteristics of noise sensitive analog IC. For the prevention of high-voltage noise, manufactured module is used the ground-isolated technique and via stitching, and is connected grounds with a series of filters. In this paper, so we analyzed PDN structure through the simulation using lumped modeling and confirmed through measurement. Simulation results, when connecting 4.7uH inductor, we made certain that noise of -7dB decreases much more than when it did not. And it was confirmed 12% less than Background Noise.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.5
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• pp.22-28
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• 2003

This paper describes the frequency dependence of the grounding impedance. In order to propose the evaluation method of the transient response of powered grounding systems, the grounding impedances were measured with varying the frequency of incoming currents by way of the variable frequency inverter and band pass filter. The magnitude and phase of the grounding impedance were analyzed in the frequency range of 20 [Hz]∼2.1[kHz]. The grounding impedance were increased with increasing the frequency of the test current. The grounding impedance at the frequency of 2[kHz] in the actual 22.9[kV] substation grounding system was approximately 3 times as large as the 60[Hz] grounding impedance. It was found that the frequency dependence of the grounding impedance is mainly subject to the inductive reactance of the grounding conductors. As a result, it is critical to determine the shape and size of grounding grid reducing the resultant inductance in grounding systems for lightning surge protection.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.1
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• pp.169-174
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• 2018

In this paper, a design method for a wideband LPF for harmonic suppression applications is investigated. The proposed wideband LPF is comprised of four circular slot pairs with different diameters, which are added symmetrically in the ground plane of a CPW transmission line. Four circular slot pairs act as a defected ground structure and provide a wideband low pass characteristic. The circular slot with the smallest diameter is located at the side of port 1, and the diameter of the circular slot is increased as it goes toward port 2. The low pass characteristics of each circular slot are compared with the proposed wideband LPF. The final designed LPF was fabricated on FR4 substrate, and its characteristics were tested. The measured S11 characteristic was maintained at over -3.3 dB in the frequency range of 1.89-20.00 GHz band, whereas the S21 characteristic was less than -21.4 dB in the frequency range of 2.66-20.00 GHz.