• Journal of Satellite, Information and Communications
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• v.9 no.2
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• pp.12-17
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• 2014

In this paper, modified EDNMOS device with DPS (double polarity source) structure are suggested to realize stable and robust ESD (electrostatic discharge) protection performance of high voltage operating microchip. This DPS structure inserts the P+ diffusion layer on N+ source side, which in intended to block lateral extension of the electron rich region from N+ source side. Based on our simulation results, the inserted P+ diffusion layer effectively prevents the formation of deep electron channeling induced by high electron injection. As a result, our proposed DPS_EDNMOS devices could overcome the double snapback effect of conventional Std_EDNMOS device.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.644-647
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• 2004

RF 시스템에서 발룬(Balun)은 회로기판과 집적회로 사이의 임피던스 매칭에 사용되는 소자로서, 전력의 균등한 분배와 함께 180도 위상차를 만드는 역할을 하는 주요 회로부품이다. 시스템의 요구사양에 따라 balanced 임피던스가 $50\Omega$인 소자뿐만 아니라, 25 또는 100, $200\Omega$인 소자들도 많이 사용되는데, 대부분의 계측기가 $50\Omega$을 I/O 임피던스로 설정하고 있어, balanced 임피던스가 $50\Omega$이 아닌 경우 특성을 측정하기 위해서는 별도의 지그설계가 필요하다. 본 연구에서는 중심주파수가 900MHz이고, balanced 임피던스가 $100\Omega$이며, LTCC 모듈 내에 내장되는 임베디드 발룬의 최적 평가를 위한 PCB 측정지그의 구조에 대하여 설계 및 시뮬레이션을 실시하고, 이에 따라 제작된 지그를 시뮬레이션 결과와 비교하였다. 지그를 구성하는 마이크로스트림의 임피던스를 조절함으로써 유효한 측정주파수범위를 넓힐 수 있었으며, 제작된 지그는 설계치에 거의 근접한 전송특성을 나타내었다.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.9
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• pp.42-47
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• 1998

We have fabricated electron-optical lens for micro E-beam system that can overcome the limitation of current E-beam lithography. Our electron-optical lens consists of multiple silicon electrodes which were fabricated by micromachining technology and assembled by anodic bonding. The assembled system was installed in UHV chamber to observe the emission characteristics of focused electrons by the electro-optical lens. We used STM(Scanning Tunneling Microscope) tip for electron source. By performing lithography with the focused electrons with PMMA(poly-methylmethacrylate) as E-beam resist. We could draw 0.13${\mu}{\textrm}{m}$ nano-scale lines.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.1
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• pp.75-80
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• 2003

This paper presents novel compact circularly polarized(CP) operation of a annular ring slot antenna with a 45$^{\circ}$truncated in the patch and a cross-slot of unequal slot lengths. A simple configuration based on a cross-slot of unequal slot lengths on the annular ring patch is adopted to realize a small-size element antenna and used a proximity coupled feed method. Experimental results show that much wider impedance bandwidth of 7.74 % and axial ratio bandwidth of 1.9 % in GPS band(1.5 GHz).

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1534-1539
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• 2004

This experiment has been carried out to measure the process of droplet formation between water phase fluid(PVA 3%) and organic phase fluid(oil) and vector fields measured by a Dynamic Micro-PIV method in the inside of a droplet while generated. Droplet length controlled by changing flow rate conditions in microchannel. Water-in-oil(W/O) droplets successfully generated at a Y junction and cross microchannel. But oil-in-water(O/W) droplets could not be formed at a Y junction microchannel. That is, PVA 3% flow could not be detached from the PDMS surface and ran parallel with oil flow. When PVA 3% flow rate was constant, droplet length and time period decreased as oil flow rate increased, but droplet frequency increased. When PVA 3% and oil flow rate ratio was constant, droplet length and time period decreased as flow rate increased, but droplet frequency increased. All that case, Standard deviation of droplet formation have less than 5% at averaged droplet length and regular-sized droplets were reproducibly formed.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.4
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• pp.500-505
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• 2011

In this paper, two types of micro-optic submersion detection systems are proposed and demonstrated. The structures are based on the transmission and reflection of incident light, respectively. Two collimators are separated by 10 mm and installed face to face in straight line. The incident light transmits from one side of collimator to the other through the air, but the optical loss is below 1 dB. On the other hand, when the sensors are submersed into water, most of optical power scattered into water. The systems monitor the dramatical power change to alarm the submersion. Reflection type of sensor system has a Bragg grating at the end of the sensor for back-reflection of sensing signal. This is for simple configuration of systems. The performance of two sensor systems are described in detail.

• Journal of the Microelectronics and Packaging Society
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• v.14 no.4
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• pp.1-7
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• 2007

Nanoimprint lithography (NIL) is an emerging technology enabling cost-effective and high-throughput nanofabrication. To successfully imprint a nano-sized pattern, the process conditions such as temperature, pressure, and time should be appropriately selected. This starts with a clear understanding of polymer material behavior during the NIL process. In this work, the squeezing of thin polymer films into nanocavities during the thermal NIL has been investigated based upon a two-dimensional viscoelastic finite element analysis in order to understand how the process conditions affect a pattern quality. The simulations have been performed within the viscoelastic plateau region and the stress relaxation effect has been taken into account.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1137-1139
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• 1999

저가의 우수한 성능을 갖는 적외선 영상표시 소자 구현에 적합한 마이크로 볼로미터를 MEMS 기술을 사용하여 제작하였다. 작은 열질량을 갖는 마이크로미터 단위의 열적고립 구조(thermal isolation structure) 제작은 폴리이미드(PI2611)를 희생층으로 사용하여 최종적으로 ashing공정 단계에서 폴리이미드를 제거하여 마이크로 볼로미터 구조를 완성하였다. 이 때의 구조층으로는 PECVD 질화실리콘($SiN_x$) 박막, 감지층으로 산화바나듐($VO_x$) 박막을 사용하였다. 본 연구에서는 폴리이미드 패턴 형성시 건식식각 공정조건 변수에 따라서 패턴의 기울기를 조절하여 폴리이미드 측면에서 발생되는 불 균일한 박막 증착과 패터닝 문제를 개선하였다. 또한 저응력의 질화실리콘 박막을 사용하여 잔류응력에 의한 열적고립 구조의 뒤틀림 현상을 완화하였다.

• Journal of Advanced Navigation Technology
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• v.10 no.4
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• pp.326-332
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• 2006

In this study, the antenna was proposed for the omni-directional characteristic in horizontal plane. Therefore we proposed $1{\times}4$ microstrip patch array on cylindrical surface for studying microstrip patch antennas. This antenna is designed for 2.45GHz ISM band and applications. This antenna can be applied to the base station of wireless microphone and access point of wireless LAN. The length and width of the patch antenna and the width of the feed line were calculated by using the theory of microstrip patch antenna, by using the both the 2.5D and 3D EM simulators the optimized antenna characteristics are obtained. From result of measured, antenna's impedance of coaxial waveguide port was 51.915-j3.688 ${\Omega}$, the return loss was -31dB and VSWR was 1.081.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.3
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• pp.355-361
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• 2012

Though a micro pump is a crucial element in miniaturized bio-fluidic systems or drug delivery systems, it has some intrinsic disadvantages such as backward flow, pulsation of flow, low repeatability and producibility, and high cost. To overcome these limitation, a PZT disc actuated micro pump including a novel ring-shaped multi-flap check valve is introduced. To enhance the performance of the micro pump, the static behaviour of flap valve module and the micro fluidic behavior of fluids are numerically modelled and analyzed. As results of the numerical analysis, the optimal dimension and configuration of the ring-shaped multi flap valve are $1{\times}0.05$ mm and 2 (inlet side)${\times}1$ (outlet side) type. The obtained maximum flow rates and flow resolution are about 90 ml/min and 30 ${\mu}l$/stroke respectively.