• 한국광학회:학술대회논문집
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• 한국광학회 2004년도 하계학술발표회
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• pp.2-3
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• 2004

• 한국전자통신학회논문지
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• 제8권7호
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• pp.979-986
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• 2013

최근, 전기, 전자, 로봇, 의료 산업 등 전 분야에서 소형화된 크기로 고도의 지적인 기능을 가지는 MEMS 기반의 스마트 디바이스 개발에 큰 관심이 집중되고 있다. MEMS 기술은 스마트 디바이스에서 요구되는 복잡한 전기적, 기계적, 화학적 그리고 생물학적 기능들을 하나로 결합하여, 초소형, 초경량으로 설계하고, 동시에 이들 디바이스들을 대량으로 일괄 제조할 수 있기 때문에 생산성 및 실용성, 경제성 측면에서 매우 효과적이다. 따라서 본 연구에서는 다가올 MEMS 기반의 새로운 기술적 패러다임에 대비하기 위해 MEMS의 공정들을 분석하고 그 적용 사례들을 고찰함으로서 기본적인 적용 방법론을 확립한다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.436-441
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• 2008

One of important factors in designing array-type MEMS resonators is obtaining a desired frequency response function (FRF) within a specific range. In this paper Krylov subspace-based model order reduction using moment-matching with non-zero expansion points is represented to calculate the FRF of array-type resonators. By matching moments at a frequency around a specific range of the array-type resonators, required FRFs can be efficiently calculated with significantly reduced systems regardless of their operating frequencies. In addition, because of the characteristics of moment-matching method, a minimal order of reduced system with a specified accuracy can be determined through an error indicator using successive reduced models, which is very useful to automate the order reduction process and FRF calculation for structural optimization iterations.

• 대한기계학회논문집A
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• 제33권9호
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• pp.878-885
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• 2009

One of important factors in designing MEMS resonators for RF filters is obtaining a desired frequency response function (FRF) within a specific frequency range of interest. Because various array-type MEMS resonators have been recently introduced to improve the filter characteristics such as bandwidth, pass-band, and shape factor, the degrees of freedom (DOF) of finite elements for their FRF calculation dramatically increases and therefore raises computational difficulties. In this paper the Krylov subspace-based model order reduction using moment-matching with non-zero expansion points is represented as a numerical solution to perform the frequency response analyses of those array-type MEMS resonators in an efficient way. By matching moments at a frequency around the specific operation range of the array-type resonators, the required FRF can be efficiently calculated regardless of their operating frequency from significantly reduced systems. In addition, because of the characteristics of the moment-matching method, a minimal order of reduced system with a prearranged accuracy can be determined through an error indicator using successive reduced models, which is very useful to automate the order reduction process and FRF calculation for structural optimization iterations. We also found out that the presented method could obtain the FRF of a $6\times6$ array-type resonator within a seventieth of the computational time necessary for the direct method and in addition FRF calculation by the mode superposition method could not even be completed because of a data overflow with a half after calculation of 9,722 eigenmodes.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2018년도 공동국제학술발표회
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• pp.76-76
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• 2018

• Transactions on Electrical and Electronic Materials
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• 제14권4호
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• pp.172-176
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• 2013

Microelectromechanical system switches are becoming more and more popular in the electronics industry; there is a need for careful selection of the materials in the design and fabrication of switches for reliability and performance issues. The membrane used for actuation to change the state of an RF switch is made mostly using gold or aluminum. Various designs of membranes have been proposed. Due to the flexure-type structures, the design complexity increases, which makes stress analysis mandatory to validate the reliability and performance of a switch. In this paper, the effective stress and actuation voltage required for different types of fixed-fixed membranes is analyzed using finite element modeling. Effective measures are presented to reduce the stress and voltage.

• 센서학회지
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• 제14권4호
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• pp.265-271
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• 2005

In this study, a variable capacitive pressure sensor is fabricated for TPMS (Tire Pressure Monitoring System). This study is for developing sensors which consecutively measure the tire pressure given as 30 psi from the industrial standard. For improving non-linearity of the prior capacitive pressure sensors, it is suggested that touch mode capacitive pressure sensor be applied. In addition, initial capacitance is designed as small as possible for the conformity to the wireless sensor. ANSYS, commercial FEA package, is used for designing and simulating the sensor. The device is progressed by MEMS (Micro Electro Mechanical Systems) fabrication and packaged with PDMS. The result is obtained sensitivity, 1 pF/psi, through a pressure test. The simulation result is discrepant from experiment one. Wafer's uniformity is presumed as the main reason of discrepancy.

• 한국정밀공학회지
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• 제22권4호
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• pp.181-187
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• 2005

In this study, a microchip system fabricated with MEMS technology was developed to detect bioelectrical signals. The developed microchip using the conductivity of gold nanoparticles could detect the biopotential with a high sensitivity. For designing the microchip, simulations were performed to understand the effects of the size and number of nanoparticles, and the sensing width between electrodes on the detection of biosignals. Then, a series of experiment was performed to validate the simulation results and understand the feasibility of the proposed microchip design. Both simulation and experimental results showed that as the sensing width between electrodes increased the conductivity decreased. Also, the conductivity increased as the density of gold nanoparticles increased. In addition, it was found that the conductivity that changes with the nanoparticles density could be approximated by a cumulative normal distribution function. The developed microchip system could effectively apply when a biosignals should be measured with a high sensitivity.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1315-1320
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• 2003

The thermal expansion coefficient, which causes the micro failure at the interfacial state of thin films is necessary to consider for proper designing MEMS. The effect of temperature on the coefficient of thermal expansion(CTE) of $SiO_2$ and $Si_3N_4$ film was investigated. Thermal strain induced by mismatch of CTE between substrate and thin film continuously measured with resolution-improved electronic speckle pattern interferometry(ESPI). The thermal stress induced by mismatch of CTE derivate through thermal strain. The thermal expansion coefficients of thin film were calculated with the general equation of CTE and thermal stress in thin films, and it confirmed that CTE of $SiO_2$changed from $0.25{\times}10^{-6}/^{\circ}C$ to $1.4{\times}10^{-6}/^{\circ}C$ with temperature increasing from 50 to $600^{\circ}C$

• 센서학회지
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• 제22권1호
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• pp.44-48
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• 2013

For a successful commercialization of microbolometer, it is required to develop a robust package including thermal stabilizing mechanism. In order to regulate the temperature within some operating range, thermoelectric cooler is generally used but it's not easy to model the whole package due to the coupled physics nature of thermoelectric cooler. In this paper, SPICE-compatible modeling methodology of a microbolometer package is presented, whose steady-state results matched well with FEM results at the maximum difference of 5.95%. Although the time constant difference was considerable as 15.7%, it can be offset by the quite short simulation time compared to FEM simulation. The developed model was also proven to be useful for designing the thermal stabilizer through parametric and transient analyses under the various working conditions.