• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.4 s.95
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• pp.438-446
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• 2005

In this paper, the modified generalized Chebyshev rational function is presented. The new element values of prototype low pass filter are obtained by network synthesis using this rational function. This proposed filter has an equal ripple passband as same as conventional generalized Chebyshev filter, but unlike conventional filter which has only one attenuation pole at finite frequency, the proposed filter has two different from each other attenuation pole in stopband. If the harmonic frequency is set to the second attenuation pole frequency, this harmonic is suppressed efficiently. Furthermore, since the location of the second attenuation pole can be arbitrary adjusted. our filters are very available for the realization of wide stopband, particularly.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.9
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• pp.924-930
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• 2003

In this paper, a novel miniaturized microstrip duplexer with attenuation pole is proposed. A three-pole microstrip CT(Cascade Trisection) two bandpass filters have each asymmetrically prescribed transmission zero are design and fabrication. This CT bandpass filter changes coupling structure, which not only shifts the location of attenuation poles but also improves skirt characteristics. The duplexer results of measurement with the cross coupling CT bandpass filters has been yielded better isolation and sharper skirt behavior than that with a conventional bandpass filter. The results of measurement are almost similar to those of simulation results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.1
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• pp.12-18
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• 2002

In this paper a novel dielectric resonator (DR) bandpass filter (BPF) with flexible arrangement of attenuation poles is proposed. This DR filter is similar to a conventional DR filter except adding a microstrip line below a DR, which not only shifts the location of attenuation poles, but also improves skirt characteristics. The duplexer with the proposed DR BPF has been yielded better isolation and sharper skirt behavior than that with a conventional DR filter. The implemented duplexer has shown a good performance and been well agreed with the simulation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.11 s.102
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• pp.1155-1163
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• 2005

In this paper, we suggest the new method to considerably enlarge stopband without increment of filter sire and loss. The proposed low pass filter looks like outward configuration with the published Modified Generalized Chebyshev (MGC) low pass filter, but the element values completely differ from each other. The published MGC fille, had been considered only the second attenuation pole to reject(or suppress) the harmonic, whereas the stopband of the proposed filter is superior to the published MGC filter because not only the second attenuation pole but also the third harmonic of the first attenuation pole is made use of profitably. We fabricate a low pass filter according to the proposed theory. From the measurement of the fabricated filter, we can confirm that the stopband of the proposed filter is reached above 4 times wider than the conventional Generalized Chebyshev(GC) filter and above 1.7 times wider than the published MGC filter.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.3
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• pp.30-36
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• 2000

In this paper, an ultrasonic testing method for inspection of high attenuation welding area using the minimum Polarity threshold algorithm which combines the minimum amplitude selection algorithm and polarity threshold algorithm is suggested to increase the signal to noise ratio of the flow signal. In order to confirm the usefulness of the suggested algorithm, experiments were performed using four probes and standard specimens following the ASME Xl Code. As a result, scattering signals were observed from the SE(safe end) and CCSS (centrifugal casting stainless steel) materials due to the microstructural characteristical, and the detectability was reduced due to the highly attenuated signal from the weldment area, but it was conformed that using the suggested algorithm, the signal to noise ratio increased about 2.6.

• Journal of the Earthquake Engineering Society of Korea
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• v.13 no.4
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• pp.25-35
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• 2009

This paper introduces the performance of a newly developed base isolation system made from the combination of a polyurethane disk - attached pot bearing and C-shape steel dampers. Ultimate compressive load tests, ultimate rotation tests, dynamic tests, and dynamic load repeat tests have been completed to determine dynamic characteristics and to verify performance characteristics. The experimental results are compared with the analytic results. It is determined that all requirements for bridge bearing in the specifications are satisfied, and that adequate energy dissipation has occurred. The EDC and effective stiffness estimated by tests are similar to the theoretical values.

• Proceedings of the Optical Society of Korea Conference
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• 2007.07a
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• pp.167-168
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• 2007

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2001.11a
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• pp.202-206
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• 2001

In this paper a novel dielectric resonator (DR) bandpass filter (BPF) with flexible arrangement of attenuation poles is proposed. This DR filter is similar to a conventional DR filter except adding a microstrip line below a DR, which not only shifts the location of attenuation poles, but also improves skirt characteristics. The duplexer with the proposed DR BPF has been yielded better isolation and sharper skirt behavior than that with a conventional DR alter. The implemented duplexer has shown a good performance and been well agreed with the simulation.

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.279-280
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• 2008

극자외선 영역(${\lambda}$=13.5 nm)에서 기하학적 그림자 효과를 줄이기 위해 ITO 박막을 RF 스퍼터링을 사용하여 증착하였다. 이를 러더퍼드 후방산란 분석법과 X-선 반사율 분석법을 이용하여 극 자외선 영역에서 ITO 박막의 광학상수를 결정하였다.

• Journal of the Korean Ceramic Society
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• v.40 no.11
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• pp.1090-1095
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• 2003

In this paper, the modeling and design of high-Q multilayer passives and multilayer diplexer for GSM/DCS applications designed and fabricated using these passives have been investigated.. To miniaturize the system, configurations of inductor and capacitor have involved a square spiral structure and a vertically-interdigitated capacitor similar to 3D interdigital structure, respectively. Multilayer diplexers for GSM/DCS applications were designed and fabricated to apply high-Q multilayer passives to practical systems, which were designed by the proposed structural and equivalent circuit model. LPF for GSM band had the passband insertion loss of less than 0.55 dB, the return loss of more than 12 dB, and the isolation level of more than 26 dB by locating attenuation pole at 1800 MHz. HPF for DCS band had the passband insertion loss of less than 0.82 dB, the return loss of more than 11 dB, and the isolation level of more than 38 dB by locating attenuation pole at 930 MHz.