• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.12
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• pp.11-20
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• 1999

We have designed and fabricated direct-and gap-coupled microstrip hairpin-comb filters by patterning double-sided YBCO films on a single 50-mm-diameter, 0.5-mm-thick $LaAlO_3$ wafer. Both filters have a center frequency at 1.773 GHz, 12 MHz bandwidth, 0.5 dB minimum insertion loss in the passband, and very strong out-of- band rejection. Due to two attenuation poles below and above the passband, the direct-coupled hairpin-comb filter showed a better skirt characteristic than the gapcoupled hairpin-comb filter which had only one attenuation pole below the passband.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.5
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• pp.23-31
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• 2001

A very compact narrowband high-temperature superconducting microstrip filter using multiple coupled line resonators is designed and fabricated to effectively use the limited space of the wafer. The fabricated 12 pole filter has a center frequency of 1.79 GHz and a 3dB bandwidth of 7.63 MHz(0.43% fractional bandwidth). The filter also shows sharp skirt characteristics of 71 dB/MHz and 41dB/MHz blow and above the passband, respectively, and has an insertion loss of less than 0.5dB and a return loss of more than 15dB in the passband.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.12
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• pp.59-64
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• 2009

In this paper, the design of a new bandstop filter with an ultra-wide stopband is proposed using the metamaterial CRLH-TL. Instead of conventional periodic structures and multi-staged CRLH-TLs, extremely small one-cell type is adopted to circumvent the setbacks of conventional filters such as the lengthened ${\lambda}_g/2$-resonator ones or alternating impedance lowpass filter, and relatively slow skirt. Besides, for a very broad stopband, a strong coupling structure including stepped impedances is suggested and the zero-order resonance is made for effective size-reduction. The validity of the proposed design is proven through the fabrication and measurement, showing the overall size less than ${\lambda}_g/10$, the stopband wider than 12 GHz, 0.7 dB of the insertion loss.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.1
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• pp.73-77
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• 2012

In this article, we designed a wide bandpass filter in order to apply microwave reflectometry for KSTAR. The proposed wide bandpass filter consists of a metamaterial structure which is to get a wide band, a lower insertion loss, and a high skirt. This is applied to VCO's output to enhance the linearity. A pass band is 18-28 GHz and the out of pass band is stopped over 20 dB. To confirm of the metamaterial, we suggest a dispersion diagram. The proposed filter in lower band and upper band of pass band is respectively a left handed and right handed characteristics. A group delay is below 0.5 ns.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.3
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• pp.284-290
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• 2004

In this paper, two types of thin nim bulk acoustic resonator(TFBAR) ladder filters are desisted and fabricated to analyze the effects of on-wafer inductor integration. To suppress the overmode phenomenon a 1 $\mu\textrm{m}$ thick air-gap is fabricated under the TFBAR and aluminum nitride is used for piezoelectric material, while platinum is employed for the top and bottom electrodes. The Tx filter in a duplexer, which usually has a steeper skirt characteristics o the right side of the passband, is designed with four serial and two shunt resonators, namely, a 4/2 stage. Similarly, the Rx filter is devised with a 3/4 stage to create a mirrored image of the Tx filter passband characteristics. Fabricated on-wafer spiral inductors with underpass reveals the Q factor of 5～9 at 2 ㎓. Inductor integrated filters have approximately 10 to 12 ㏈ out-of-band rejection improvement, when compared to the original filters.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.12 s.115
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• pp.1199-1205
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• 2006

This paper proposes a wideband monopole antenna with improved band rejection characteristics by inserting two band notch slots with half wavelength in radiator. The designed antenna is composed of bow-tie patch fed electromagnetically with parasitic ground patch of a semicircular shape. We obtained band rejection filter-like characteristics by controlling coupling amounts between two horizontal resonance slots. Using this technique, we achieved the broad rejection bandwidth and improved skirt characteristics compared with only one notch slot. The measured bandwidth is from 2.7 GHz to 6.9 GHz for VSWR below 2.0 except the limited band of $4.96{\sim}5.51GHz$. This antenna shows a similar radiation pattern of the ideal monopole and the radiation gain reduction is more than $5{\sim}10dB$ on the x-z plane at rejection frequency.

• 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.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.8
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• pp.913-921
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• 2007

In this paper, we propose a novel small antenna for direction finding applications. The proposed antenna employs a skirt type disk to eliminate the radiation null on the broad-side direction in the high frequency range. Additionally, the multi-section matching stub is used for impedance matching in the low frequency range, The size of the proposed antenna is reduced as a half of the 60cm dipole which has a same resonance frequency of 200MHz. The antenna maintains a donut shape radiation pattern with a broad beam width for a wide range of frequency while the 60cm dipole shows radiation nulls on the broad-side direction and the high side-lobe level from 700MHz to 1,300MHz.

• Journal of Korean Home Economics Education Association
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• v.4 no.1
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• pp.57-75
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• 1992

The purpose of this study was to survey the actual condition of education on the western clothing construction in Home Economics and Housework curriculum of high school. And the finding of this study will the helpful to the persons in authority who take part in the course of compilation of the western clothing contruction. The subjects of this study were 101 high school teachers in Chonbuk province. Their responses to the questionaires were analyzed by frequencies and percentiles. The major findings of the study were as follows. 1. Most high school had only a little educational facilities for learning of clothing construction of, if any, they could only show examples in practice. 2 In case of making clothes, students who sew by hand carried out drafting and cutting on their desks in the classroom. When they have practical training, 56.4% of them cheese only one of one-piece dress trousers, and skirt which are presented in the textbook. The related teachers indicated that content composition of the texbook was not fit for the purpose of the students level, and also pointed out the deficiencies of educational facilities, lack of teacher’s research and training, and lack of school hours of evaluation, practical skill was performed in parallel with paper-test at 73.3%. 3. Pajamas and one-piece dress presented in the textbook were the most suitable for the practice at 64.7%. They hoped that illustrations in textbook are so large and full that clothes made through the practice can be worn. Also they hoped that their opinions and wearable guidance will be reflected in the textbook. They emphasized the need of western clothing construction unit because of acquistion of elementary knowledge. The current amount of content composition was enough or excessive. In addition, they understood the curriculum of high school is rather closely connected with that of middles school. Their recognition of the rate of difficulty is very similar to that of other school teachers. They recognized the goal of learning should be applied to the real home life.

• Journal of the Korean Society of Costume
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• v.12
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• pp.39-54
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• 1988

The purposes of this study were to identify the periodicity of fashion in modern society and to find the correlation between each detail and bustle constitution through the bustle styles that have been recently revived. For the study of periodicity, fashion plates or pictures in Vogue or in the books related Vogue since 1930 were selected, and were analyzed into bell, tubular and bustle silhouettes that were devided by Young (1937). And for the study of the correlation of detail and bustle constitution, fashion plates and pictures that were related to the bustle in the 19th century and the 20th century were selected, and according to the epoch (19C, 20C) and the use (daytime dress or evening dress), each of them was analyzed. The results were as follows: 1. After 1930, $24{\sim}33$ year amplitude was founded at tubular and bell shape, that proved shorter cycles than Young's. 2. In each characters of clothing details, deep decolletage, undivided waistline, spaced bodice in daytime dress were partly identified the characteristics of 20th century costume. 3. The form of bustle was converted from the complex ornament of the 19th century to the simple shape of the 20th century. In other words, it is necessary that the definition of bustle be changed not the previous definition as the silhouette and instrument but that as the emphasis dimension. 4. The dimensions that showed difference at daytime dress and evening dress were 'existence of collar', 'neckline', 'length of sleeve', 'kind of sleeve' for 19th century, and 'neckline', 'length of sleeve', 'kind of sleeve,' 'length of skirt' for 20th century. 5. Correlations with the bustle constitution and details were shown at bodice and waistline with the complex bustle in the 19th century and at collar and neckline with the simple bustle in the 20th century.