• 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.639-647
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• 2007

This paper proposed the novel method that can realize the parallel coupled line(PCL) band-pass filter with directly coupled feeding structure by means of transforming the first and last PCL sections of the conventional PCL band-pass filter into K-inverters, then substituting T-type equivalence for K-inverter. The proposed method supplies simple design formulae and can considerably reduce time and efforts needed to optimize filter performance when compared to reported methods using external Q or equivalent parameters. On the basis of the proposed method, the band-pass filter using directly coupled feeding structure and having 18% fractional bandwidth was designed and fabricated. The validity of proposed method was proven by the measured result.

• 한국ITS학회:학술대회논문집
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• v.2006 no.10
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• pp.175-178
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• 2006

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1345-1347
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• 2008

This paper described a method of determining whether arcing is present in a low-voltage wiring system. We simulated the series arcing that generated in electrical loads and fabricated a arc detection module which can discriminate between normal and arcing state. The module consists of a high-pass filter with a low cut-off frequency of 3 kHz to attenuate power frequency voltage and an active band-pass filter with a frequency of 4 kHz ${\sim}$ 8 kHz to detect series arc signals only. We tested an Incandescent lamp that was controlled by a dimmer and analysed. The module consists of a high-pass filter with a low cut-off frequency of 3 kHz to attenuate power frequency voltage by 80 dB and an active band-pass filter with a frequency of 4 kHz to detect series arc signals only. From the experimental results, we could detect series arc signals without an influence of non-linear loads.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.2
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• pp.260-267
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• 2014

In this paper, the unit cell of LH structure using microstrip transmission line and chip capacitor is devised, and the reactive components of equivalent circuit are extracted from the proposed unit cell. And then, we have analyzed for the unit cell parameters and applied the characteristics to the wideband high pass filter design. This filter cascading several unit cells with high pass property has been implemented on microstrip transmission line, and the performance has been the band rejection characteristics of 62.9 dB in the stop band to 0~2.18 GHz and less than the insertion loss of 1.17 dB in the pass band from 3.0G Hz to 12.75 GHz.

• Journal of Advanced Navigation Technology
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• v.22 no.1
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• pp.27-30
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• 2018

In this study, a 40 GHz band pass filter(BPF) employing a hair-pin structure has been designed, fabricated, and characterized for millimeter-wave wireless communication applications. Using the 3 dimensional(3-D) electromagnetic(EM) tool and design equations of the hairpin BPF, the BPF was desgned on the 5 mil-thick Duroid substrate(RT5880) with a relative dielectric constant (${\varepsilon}_r$) of 2.2. The tapping point (t) of the U-shape resonator in the input and output port has been determined using extracted an external Q-factor ($Q_e$). The coupling coefficients between the other resonators are calculated by adjusting the physical dimensions for the desired response of the BPF. The fabricated BPF was characterized using probing method on a probe station. Its measured center frequency(fc) and fractional BW are 41.6 GHz and 7.43 %, respectively. The measured return loss is below -10 dB at the pass band and the insertion loss is 3.87 dB. The fabricated BPF is as small as $9.1{\times}2.8mm^2$.

• 한국ITS학회:학술대회논문집
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• v.2006 no.10
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• pp.187-190
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• 2006

In this paper, the equivalent circuit of tapped-line that is applied in the feeding of the band-pass filter with high coupling is suggested and the value of an equivalent circuit is mathematically defined. An equivalent circuit of tapped-line is composed by open stub and additional transmission line, and the electrical lengths of stub and line can be obtained by the impedance of resonator and the inverter. The new equivalent circuit of tapped-line can be simply applied of design of band-pass filter and leads to very good agreement compared with theoretical value. The coupled-line band-pass filter using equivalent circuit of tapped-line shows the insertion loss of 1.97 dB and the return loss of 18.5 dB at the center frequency of 5.8 GHz.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.9
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• pp.904-911
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• 2011

This paper deals with transmission characteristics of a new dual resonant structure for designing waveguide band-pass filter. The structure which has a pass-band between two adjacent stop-bands in a single body consists of circular ridged aperture and four armed conducting patch. The dual resonant behavior of the structure can be represented by a combination of LC series and parallel resonant circuits. Also these resonant properties can be easily controlled by varying the geometry of the aperture and four armed conducting patch. Actually, the structure is fabricated on the microstrip substrate by use of etching technique so that it is formed an iris type resonator which can be easily put into the transverse plane of the waveguide. We use WR-90 standard waveguide, adapters, and VNA(vector network analyzer) to measure the resonant characteristics of the structure. It is very useful to design and to improve the cutoff skirts characteristics in the waveguide band-pass filter design area.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.12
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• pp.21-30
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• 1999

Several kinds of design method for the hairpin type band-pass filter have been reported. The conventional design methods have some restrictions in characteristic impedance of coupled line section, which provide complexities to designer. In this paper, the novel design formulas for the hairpin type band pass filter have been derived and proposed to resolve the problems of the reported design methods. By employing the equivalent circuit of the coupled line section and band pass filter design theory, the design procedures and formulas are derived. The hairpin type RX/TX band pass filters for the IMT-2000 service have been designed, fabricated with duplexer configuration, and then measured to show the validity of the proposed design method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.8
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• pp.884-890
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• 2008

In this paper, Characteristics responded to frequency of a band-pass filter with admittance inverters(J-inverters) is considered. As a result, it is confirmed that attenuation characteristics of upper and lower frequency is asymmetric. And a modified circuit and design formulas are proposed to improve the asymmetric attenuation characteristics. By confirming the simulated and measured results that are got from designed and made a experiment on the band-pass filter with the proposed circuit and formulas for design, we confirm that the asymmetric attenuation characteristics of the band-pass filter are improved without any optimization or iterative design procedures and additional calculation efforts.

• Applied Microscopy
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• v.42 no.2
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• pp.105-109
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• 2012

Electron tomography (ET) of biological specimens is performed from a series of images obtained over a range of tilt angles in a transmission electron microscope. When using the high voltage electron microscope (HVEM), various noises appear in EM images acquired from thick sections by high voltage electron beam. In order to obtain an adequate result in electron tomograms that allow visualization of rather complex and mega-cellular structure such as brain tissue, it is necessary to remove the noise in each original tilt images of thick section. Using band-pass filtering of original tilt images, the filtered images are obtained and used to assemble a reconstructed tomogram. The qualified 3D tomogram from filtered images results in a considerable reduction of the noises compared to conventional tomogram. In conclusion, this study suggests that band-pass filtering is effective to improve the brightness and intensity of HVEM produced tomograms acquired from micron-thick sections of biological specimens.