• Journal of electromagnetic engineering and science
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• v.5 no.3
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• pp.112-116
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• 2005

This paper presents a broadband two-stage low noise amplifier(LNA) operating from 3 to 10 GHz, designed with 0.18 ${\mu}m$ RF CMOS technology, The cascode feedback topology and broadband matching technique are used to achieve broadband performance and input/output matching characteristics. The proposed UWB LNA results in the low noise figure(NF) of 3.4 dB, input/output return loss($S_{11}/S_{22}$) of lower than -10 dB, and power gain of 14.5 dB with gain flatness of $\pm$1 -dB within the required bandwidth. The input-referred third-order intercept point($IIP_3$) and the input-referred 1-dB compression point($P_{ldB}$) are -7 dBm and -17 dBm, respectively.

• Research in Mathematical Education
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• v.15 no.1
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• pp.1-14
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• 2011

Logo has influenced many researchers and learners for the past decades as a 20 turtle geometry environment in the perspective of constructionism. Logo uses the metaphor of 'playing turtle' that is intrinsic, local and procedural. We, then, design an environment in which the metaphor of 'playing turtle' is applied to construct 3D objects, and we figure out ways to represent 3D objects in terms action symbols and 3D building blocks. For this purpose, design three kinds of representation systems, and asked students make various 3D artifacts using various representation systems. We briefly introduce the results of our investigation into students' cognitive burden when they use those representation systems, and discuss the future application measures and the design principles of Logo-based 3D microworld.

• Journal of the Microelectronics and Packaging Society
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• v.20 no.1
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• pp.15-19
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• 2013

The n-type $Bi_2(Te_{0.9}Se_{0.1})_3$ powders, which were fabricated by melting/grinding method and dispersed with 0.5 vol% $TiO_2$ nanopowders, were hot-pressed in order to investigate the effects of $TiO_2$ dispersion on the thermoelectric properties of the hot-pressed $Bi_2(Te_{0.9}Se_{0.1})_3$. Excellent thermoelectric properties such as a maximum figure-of-merit of $2.93{\times}10^{-3}/K$ and a maximum dimensionless figure-of-merit of 1.02 were obtained for the hot-pressed $Bi_2(Te_{0.9}Se_{0.1})_3$. With dispersion of 0.5 vol% $TiO_2$ nanopowders, the maximum figure-of-merit and the maximum dimensionless figure-of-merit decreased to $2.09{\times}10^{-3}/K$ and 0.68, respectively.

• Journal of the Korean Society of Clothing and Textiles
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• v.42 no.2
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• pp.211-223
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• 2018

In global apparel product development, flat is one of the most important key factor for technical design communication. Proportionally correct flats based on correct scaled human body figures are imperative to be successful in the fashion business. In this study the researchers were to develop body templates for flats for Korean women body types using data from 'Size Korea 2004 (5th)', which is a Korean government apparel sizing project to analyze women's body measurements (age range 7-49). We measured 13 height measurements, 6 width measurements, 8 circumference measurements, 6 length measurements, 3 angle measurements and 5 body measurements. A body figure (i.e., schema) for each group was created by Pattern Design Software (PAD) System 4.1. Muscle was added to the schema created by Adobe Illustrator to ensure a better visualization and convenience for industry uses for flats. Developed body figure template of representative type had the largest difference in height level compared to exiting figures. It had a bigger head, lower crotch level, and longer crotch depth and hip length than existing figures.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.11
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• pp.1536-1543
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• 2004

Garment is made by a 2D pattern and should be fitted to a human body which has 3D characteristics. Therefore, to design a pattern more effectively, the use of 3D information of a human body and the investigation of relationship between the 3D garment and 2D pattern are necessary. In this work, ruled surface method was used to reflect the 3D information of a human body for a pattern design. The images of the brassiere line on the woman's dress form were captured by phase-shifting projection moire system and the 3D information on the design line was obtained. 2D patterns on the various parts of the brassiere were developed directly from the 3D data by the ruled surface method. In addition, design line, the area and the amount of dart were quantified. And then we verify the appropriateness of the ruled surface method to the 2D pattern development by measuring the distribution of the space between women's figure and segmented clothing item. It was found that the ruled surface method is useful to transform the 3D design line to the 2D pattern, if we followed the steps suggested in this paper.

• The Research Journal of the Costume Culture
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• v.28 no.1
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• pp.1-14
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• 2020

This study is based on a representative body shape drawn from previous studies that classify adult male torso shapes. In this study, a design method is proposed by developing a tight-fit pattern that can be easily developed into various items and designs using the body surface development figure. This is obtained by converting the 3D body shape of the model representing the representative body shape. The specific design method was conducted as follows. Actual measurement values were used for waist back length, waist-to-hip length, shoulder length. The scye depth was determined as C/4-1.7 cm, and the front and back Interscye was set at (1/2 × actual measurements)-0.2 cm. The front-back neck breadth was set to (1/5 × base neck circumference)-1.3 cm and (1/5 × base neck circumference) cm. The front-back neck depth was set to (1/5 × base neck circumference)-1.2 cm and 3.5 cm. Front chest circumference was C/4-1 (front-back difference)cm; (1/4 × back chest circumference) was C/4 + 1 (front-back difference) + 0.3 (dart amount) cm. Front waist circumference was W/4-0.2 (front-back difference) + 2.2 (dart amount) cm; back waist circumference was W/4 + 0.2 (front-back difference) + 2.5 (dartamount) cm; front hip circumference was H/4 + 0.2 (ease) + 0.2 (front-back difference) cm; and back hip circumference was H/4 + 0.2 (ease)-0.2 (front-back difference) cm; Front droop was 1.6 cm. The newly developed tight-fit pattern is expected to be of great use as a basis for garment construction.

• ETRI Journal
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• v.18 no.3
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• pp.171-179
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• 1996

Fully passivated low noise AlGaAs/InGaAs/GaAs pseudomorphic (PM) HEMT with wide head T-shaped gates were fabricated by dose split electron beam lithography (DSL). The dimensions of gate head and footprint were optimized by controlling the splitted pattern size, dose, and spaces of each pattern. We obtained stable T-shaped gate of $0.15{\mu}m$ gate length with $1.35{\mu}m-wide$ head. The maximum extrinsic transconductance was 560 mS/mm. The minimum noise figure measured at 18 GHz at $V_{ds}=2V andI_{ds}=17mA$ was 0.41 dB with associated gain of 8.19 dB. At 12 GHz, the minimum noise figure and an associated gain were 0.26 and 10.25 dB, respectively. These noise figures are the lowest values ever reported for GaAs-based HEMTs. These results are attributed to the extremely low gate resistance of wide head T-shaped gate having a ratio of the head to footprint dimensions larger than 9.

• ETRI Journal
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• v.33 no.3
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• pp.462-465
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• 2011

A millimeter-wave (mm-wave) high-linear low-noise amplifier (LNA) is presented using a 0.18 ${\mu}m$ standard CMOS process. To improve the linearity of mm-wave LNAs, we adopted the multiple-gate transistor (MGTR) topology used in the low frequency range. By using an MGTR having a different gate-source bias at the last stage of LNAs, third-order input intercept point (IIP3) and 1-dB gain compression point ($P_{1dB}$) increase by 4.85 dBm and 4 dBm, respectively, without noise figure (NF) degradation. At 33 GHz, the proposed LNAs represent 9.5 dB gain, 7.13 dB NF, and 6.25 dBm IIP3.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.10
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• pp.1169-1176
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• 2010

The RF front-end for L1/L2 dual-band Global Positioning System(GPS) receiver is presented in this paper. The RF front-end(down-converter) using low IF architecture consists of a wideband low noise amplifier(LNA), a current mode logic(CML) frequency divider and a I/Q down-conversion mixer with a poly-phase filter for image rejection. The current bleeding technique is used in the LNA and mixer to obtain the high gain and solve the head-room problem. The common drain feedback is adopted for low noise amplifier to achieve the wideband input matching without inductors. The fabricated RF front-end using $0.18{\mu}m$ CMOS process shows a gain of 38 dB for L1 and 41 dB for L2 band. The measured IIP3 is -29 dBm in L1 band and -33 dBm in L2 band, The input return loss is less than -10 dB from 50 MHz to 3 GHz. The measured noise figure(NF) is 3.81 dB for L1 band and 3.71 dB for L2 band. The image rejection ratio is 36.5 dB. The chip size of RF front end is $1.2{\times}1.35mm^2$.

• Journal of the Korean Magnetics Society
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• v.10 no.3
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• pp.99-105
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• 2000

One dimensional magneto-photonic crystal having structure of (A/B)$^{k/W}$(B/A)$^{k}$ , where M is a magnetic layer of highly Bi-substituted iron garnet, A and B are dielectric layers of $SiO_2$ and T $a_2$O$_{5/}$, and k is the stacking number of the dielectric layers, has been numerically analyzed as a function of the thickness (d$_{M}$) of M (1∼535 nm) and the stacking numer of k (5∼15). The transmittance, Faraday rotation, and figure of merit of the magneto-photonic crystal have been investigated both in the visible and infrared wavelengths. A factor of several and several tens greater Faraday rotation and figure of merit have been obtained compared to the single layer of M, at many localized modes. In the visible the maximum figure of merit of 0.15 was obtained ( = 720 nm) when k = 11 and d$_{M}$ = 375 nm with T : 0.54, $\theta$$_{F}$ = 8.13$^{\circ}$, which was a factor of 30 greater than that of single garnet layer. Much greater maximum figure of merit, 0.285, was obtained in the infrared ( = 1114 nm) when k = 11 and d$_{M}$ = 800 nm with T = 0.66, $\theta$$_{F}$ = 18$^{\circ}$, which was a factor of 100 greater than that of single garnet layer.