• Journal of the Korean Vacuum Society
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• v.20 no.3
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• pp.233-241
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• 2011

Currently, solar module is using the two methods such as a glass-filled method or a super-straight method. The common point of these methods is to use glass structure on the front of solar module. However, the reflectance of the solar module is high depending on the height of the incident sunlight due to the flat surface of the module front glass. Purposed to solve these problems, AG (anti-glare) structures were formed on the glass surface. Next is fabrication methods of AG structure. First, uneven structure made by micro blaster equipment was dipped in Hydro-fluidic acid (HF) acid. HF acid process was carried out to remove particles and to make high transmittance. The reflectance and transmittance of the anti-glare glass was compared to those of the bare glass. The reflectance of anti-glare glass decreased approximately 1% compared with bare glass. The transmittance of anti-glare glass was similar to bare glass. According to the sample angle, the difference of the reflectance between bare glass and the anti-glare glass was about 19%. Isc and efficiency value of anti-glare glass on bare solar cell appeared about 3.01 mA and 0.228% difference compared with bare glass. Anti-glare glass on textured solar cell appeared about 9.46 mA and 0.741% difference compared with bare glass. As a result, the role of anti-glare in the substrate is to reduces the loss of sunlight reflected from the surface. In this study, therefore, AG structure on the solar cell was used to improve the efficiency of solar cell.

• Korean Journal of Optics and Photonics
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• v.28 no.2
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• pp.59-67
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• 2017

This paper proposes an asymmetric split-loop resonator with an outer square loop (ASLR-OSL), which can actively control terahertz wave transmission properties while maintaining a high-Q-factor of the asymmetric split-loop resonator (ASLR). An added outer square loop is designed to play the roles of both a metamaterial and a micro-heater, which can control the temperature through a directly applied bias voltage. A vanadium dioxide ($VO_2$) thin film, which exhibits an insulator-metal phase transition with temperature change, is used to control the transmission properties. The proposed ASLR-OSL shows transmission properties similar to those of the ASLR, and they can be successfully controlled by directly applying bias voltage to the outer square loop. Based on these results, an electrically controllable terahertz high-Q metamaterial could be achieved simply by adding a square loop to the outside of a well-known high-Q metamaterial.

• Korean Journal of Materials Research
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• v.3 no.6
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• pp.598-605
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• 1993

Methacryloxyethyl dimethyl alkyl($C_{1}\sim C_{12}$, benzyl and 2, 2-diethoxy ethyl) ammonium bromide monomers were prepared to investigate the relative humidity characteristics for polymer electrolytes with different chemical structures. They were coated on the alumna substrate printed comblike gold electrode by photopolymerization after micro-syringe injection. As the thickness of rhe humid membrane increased, the impendance decreased, whereas the impedance ~ncreased as the carbon cham of alkyl substituent in the monomer increased. The impendance of the polymeric electrolytes with $C_6\sim C_8$ substituents were varied from 19M$\Omega$ to 5K$\Omega$ for the range of 30-90% Mi. The temperature depedence coefficient in the range of 15-$35^{\circ}C$ was found to be -0.45% $RH/^{\circ}C$and the hysteresis falled within the range of $\pm$2% RH. The response time was 35 second for varying humldity from 33% to 85% RH.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.13 no.1
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• pp.61-66
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• 2014

This paper describes the design, fabrication, and measurement of a compact hexa-band coupling antenna for 4G mobile handset using a small element with two slots. In order to obtain sufficient bandwidth (LTE700, GSM850, GSM900, GSM1800, GSM1900, UMTS) with a Voltage Standing Wave Ratio $(VSWR){\leq}3:1$, two slots are inserted in the small element, and coupling patch is used. The measured result of the fabricated antenna provides 410MHz bandwidth form 0.688 to 1.098GHz and 643 MHz bandwidth form 1.607 to 2.250GHz (${\leq}VSWR 3:1$) with the gain ranging from -0.52 to 4.68 dBi. Also, a good radiation pattern is achieved within the hexa-band (0.698-0.960GHz and 1.710-2.170GHz) range.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.185-190
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• 2015

In this paper we characterized and designed the waveguide antipodal finline transition at 57-65GHz frequency band in V-band for 5G mobile communication systems. Especially, we proposed the design method of spline taper for finline tapers by means of increasing curvature from linear taper. We could perform optimization more effectively by excluding improper regions for optimal performance from optimization using the method. Return losses and insertion losses of antipodal finline transitions were mainly affected by the taper shape of the finline. The resonances in the structure of the finline transition were the strongest enemies who deteriorate the performance of the transition. And we alleviated the resonances using semicircle shaped patch. The designed antipodal finline transition showed good performance as it showed less than -24.2dB of return loss and -0.24dB of insertion loss in the band(57-65GHz) which we suppose to use.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.5
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• pp.421-426
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• 2008

The magnetic bio-sensor used the PHR (planar hall resistance) effect generated by the free layer in spin-valve giant magnetoresistance structure of Ta/NiFe/CoFe/Cu/NiFe/IrMn/Ta. The PHR element with micrometer size was fabricated through the photolithograph and dry etching process. The PHR signal with magnetic field was measured under the conditions of with and without single magnetic bead. A single magnetic bead of diameter $2.8\;{\mu}m$ was successfully detected using the PHR sensor. Therefore, the high resolution PHR sensor can be applied to bio-sensor application utilizing the output voltage variation of the PHR signals in the presence and absence of a single magnetic bead.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.475-475
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• 2013

Cuprous oxide ($Cu_2O$)는 밴드갭이 2.17 eV p-type 산화물 반도체로써 태양에너지 변환기, photocatalysis (광촉매작용), 센서, 스위칭 메모리 등 응용이 다양한 재료이다. 산화물 반도체의 기본 특성은 나노/마이크로 범위 안에서 재료의 표면형태, 크기, 구조와 형상 공간방향등에 크게 영향을 받는다. 그렇기 때문에 원하는 $Cu_2O$ 특성을 얻기 위해서 성장 거동을 아는 것은 매우 중요하다. RF 마그네트론 스퍼터법으로 rod 성장 사례는 잘 알려지지 않았다. 그래서 RF 마그네트론 스퍼터법 $Cu_2O$ rod 형성 실험을 통하여 $Cu_2O$ 형성과 성장 거동을 알아보았다. RF 마그네트론 스퍼터법으로 $Cu_2O$ rod를 glass 기판 위에 Cu metal target을 이용하여 형성시켰다. $Cu_2O$ rod 합성을 위해 기판온도 및 산소분압 O2/(Ar+O2)=3%, 5%, 7% 증착시간 등을 변화시켜 실험하였다. 성장된 rod의 분석은 XRD, SEM으로 확인하였다. 성장 거동은 증착온도와 증착시간에 차이를 보였다. 증착온도 $550^{\circ}C$에서 rod가 생성되는 것을 관찰하였다. 증착시간이 길어질수록 rod 길이가 길어지고 일정 시간이 지나면 rod의 길이 성장보다는 두께(폭)가 성장하는 것을 확인하였다. 증착온도 $550^{\circ}C$ 그리고 산소분압 3%, 5%, 7% 조건에서 rod 합성 실험을 하였을 때 3%, 5% 조건에서 rod의 성장을 확인하였다. 이때 3%, 5% 산소분압에 따라 rod의 모양이 변화하였다. 하지만 7% 조건에서는 rod가 성장하지 않았다. 이유는 3%, 5%에서는 Cu metal peak을 확인하였지만, 7% 조건에서는 Cu metal peak이 없었다. 이로부터 Cu metal이 $Cu_2O$ rod 생성에 영향을 미치는 중요한 요소임을 예상할 수 있었다.

• Journal of Sensor Science and Technology
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• v.10 no.3
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• pp.173-179
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• 2001

The currently used semiconductor pressure sensors are piezoresistive and capacitive type. Especially, semiconductor micro pressure sensors have a great deal of attention because of their small size. However, its fabrication processes are difficult, so that its yield is poor. For the purpose of resolving the drawbacks of the existing silicon pressure sensors, we demonstrate a new type of pressure sensor using PSFET(pressure sensitive field effect transistor) and investigate its operational characteristics. We used PZT(Pb(Zr,Ti)$O_3$) as a pressure sensing material. PZT thin films were deposited on a gate oxide of MOSFET by an rf-magnetron sputtering method. To abtain the stable phase, perovskite structure, furnace annealing technique have been employed in PbO ambient. The sensitivity of the PSFET was 0.38 mV/mmHg.

• Journal of Internet Computing and Services
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• v.6 no.4
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• pp.21-35
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• 2005

Software product-lines is the software development paradigm to attain the rapid development of quality applications by customizing the reconfigurable components and composing them based on predefined software architectures. Recently various methodologies for the component-based product lines are proposed, but these don't provide the specific implementation techniques of the components in terms of variability resolution mechanism. In other hand, the several approaches to implement the component supporting the variabilities resolution are developed, but these don't define the systematic analysis and design method considering the variabilities from the initial phase. This paper proposes the integration of PLUS, the one of product line methodologies extending UML modeling, and component code generation technique in order to increase the efficiency of producing the specific product in the software product lines. In this paper, the component has the hierarchical architecture consisting of the implementation elements, and each implementation elements are implemented as XSLT scripts. The codes of the components are generated from the feature selection. Using the microwave oven product lines as case study, the development process for the reconfigurable components supporting the automatic variability resolution is described.

• 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.