• 한국군사과학기술학회지
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• 제9권2호
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• pp.103-110
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• 2006

We present a W-band radiometer to detect the metal targets on the ground environment. The type of the designed radiometer is the total power radiometer(TPR) for the simple configuration. The front end of the TPR consists of only the Mixer and LO for miniaturizing the system. Because the radiometer system does not use the low noise amplifier, we use matching circuits and a diode detector configured as a voltage doubler to compensate the degradation of sensitivity. We solve the temperature variation problems by filtering the reference voltages of the radiometer output signals. Through some experiments, we have verified that the designed radiometer system has good performances in detecting metal targets lying at several hundred meters.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.592-593
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• 2012

Buck converter must operate at fairly high switching frequency for miniaturizing a whole circuit and achieving a fast response. However, at the conditions of low output voltage, high output current, and high switching frequency, the influence of parasitic elements to circuit operation will become extremely obvious. In this paper, it has been shown that these parasitic elements of output capacitor link the ripple of the output voltage. The MCP capacitors and aluminum electrolytic capacitors are applied to the buck converter and observed characteristics and the experimental results were reported.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.739-739
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• 2005

In the conventional AF lens actuating system the VCM actuator is used. However due to the actuating mechanism, the VCM actuator has disadvantage in miniaturizing which is essential to the actuator for the mobile device. Therefore novel type actuator is required and the one of the candidate is actuator using electoractive polymer (EAP). The EAP actuator is one of the attractive smart materials that is light and can be easily fabricated with low cost. This paper proposes an AF lens actuator for mobile phone using dielectric elastomer. The proposed actuator was designed and analyzed using finite element method. The designed actuator is verified by experiment and the position control algorithm is applied.

• 전자공학회논문지D
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• 제35D권11호
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• pp.23-30
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• 1998

수동 소자를 위한 대표적 구성요소의 하나인 마이크로스트립을 이용하는 소자는 넓은 점유면적으로 인하여 고주파 집적회로의 소형화를 제한하는 중요한 요인이 되고 있다. 본 논문에서는 신호의 진행 방향으로 마이크로스트립 도체를 주기적으로 천공함으로써 slow-wave 효과를 얻는 천공된 마이크로스트립을 제안하고 해석과 실험을 통하여 성능의 우수성을 확인하였다. 천공된 마이크로스트립의 특성 임피던스 정합(50 Ω)과 Q 값 등은 기존의 변조된 폭을 갖는 마이크로스트립보다 향상됨을 관찰하였다. 본 천공된 마이크로스트립은 그 구조의 단순함으로 보다 우수한 Q 값을 얻을 수 있으며 초고주파 소자의 소형화에 매우 효과적으로 이용될 것이다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.78-78
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• 2015

Metamaterials, artificially structured nanomaterials, have enabled unprecedented phenomena such as invisibility cloaking and negative refraction. Especially, hyperbolic metamaterials also known as indefinite metamaterials have unique dispersion relation where the principal components of its permittivity tensors are not all with the same signs and magnitudes. Such extraordinary dispersion relation results in hyperbolic dispersion relations which lead to a number of interesting phenomena, such as super-resolution effect which transfers evanescent waves to propagating waves at its interface with normal materials and, the propagation of electromagnetic waves with very large wavevectors comparing they are evanescent waves and thus decay quickly in natural materials. In this abstract, I will focus discussing our efforts in achieving the unique optical property overcoming diffraction limit to achieve several extraordinary metamaterials and metadevices demonstration. First, I will present super-resolution imaging device called "hyperlens", which is the first experimental demonstration of near- to far-field imaging at visible light with resolution beyond the diffraction limit in two lateral dimensions. Second, I will show another unique application of metamaterials for miniaturizing optical cavity, a key component to make lasers, into the nanoscale for the first time. It shows the cavity array which successfully captured light in 20nm dimension and show very high figure of merit experimentally. Last, I will discuss the future direction of the hyperbolic metamaterial and outlook for the practical applications. I believe our efforts in sub-wavelength metamaterials having such extraordinary optical properties will lead to further advanced nanophotonics and nanooptics research.

• 한국광학회:학술대회논문집
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• 한국광학회 2009년도 동계학술발표회 논문집
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• pp.387-388
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• 2009

바이오포토닉스는 생물학과 포토닉스의 융합학문으로 특히, 최근 바이오이미징기술, 광바이오센서, 광조절 및 바이오칩의 광학센서시스템 및 광학집게 개발등에 큰 관심을 받고 있고 다양한 융합연구를 창출하고 있다. 미세기전시스템(MEMS: Microelectromechancial system)은 센서나 구동기를 초소형화 하기 위해 매우 유용한 기술로서 지난 10여년간 광통신분야에서 미세광학소자 및 집적광통신 반도체소자개발에 응용되어왔다. 최근 이러한 MEMS 기술을 이용하여 고감도 바이오센서나 고분해능, 실시간 바이오 이미징시스템을 초소형하는 연구가 활발히 진행되고 있다. 본 연구에서는 바이오포토닉스 응용을 위한 광학소자의 초소형화 기술의 장점과 응용가능분야에 관해 소개하고자 한다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 추계학술발표대회
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• pp.4.1-4.1
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• 2009

The dream of futurists andtechnologists is to build complex, multifunctional machines so small that theycan only be seen with the aid of a microscope. The unprecedented technologyadvancements in miniaturizing integrated circuits on semiconductors, and theresulting plethora of sophisticated, low cost electronic devices demonstratethe impact that micro/nano scale engineering can have when applied only to thearea of electrical and computer engineering. Emerging research efforts indeveloping organic and inorganic nano materials together with using micro/nanofabrication techniques for implementing integrated multifunctional devices hopeto yield similar revolutions in other engineering fields. By cross linking theindividual engineering fields through micro/nano technology, various organicand inorganic materials and miniaturized system devices can be developed thatwill have future impacts in the IT and life science applications. Yet to buildthe complex micromachines and nanomachine of the future, engineering will needto develop the technology capable of seamlessly integrating these materials andsubsystems together at the micro and nano scales. The micromachines of thefuture will be “integrated nanosystems,” complex devices requiring the integration of multiple materials,phenomena, technologies, and functions at the same platform. To develop thistechnology will require great efforts in materials science and engineering, infundamental and applied sciences. In this talk, we will first discuss thenature of micro and nanotechnology research for IT and life sciences, and thenintroduce selected current activities in micro and nanotechnology research fororganic and inorganic materials and devices. The newly developed micro/nanofabrication processes and devices, combined with in-depth scientificunderstandings of materials, can lead to rapid development of next generationsystems for applications in IT and life sciences.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.1-4
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• 2008

Fuel cells have the potential of providing several times higher energy storage densities than those possible using current state-of-the-art lithium-ion batteries, but current energy density of fuel cell system is not better than that of lithium-ion batteries. To achieve the high energy density, volume and weight of fuel cell system need to be reduced by miniaturizing system components such as stack, fuel tank, and balance-of-plant. In this paper, the thin flexible PCB (Printed circuit board) is used as a current collector to reduce the stack volume. Two end plates are made from light weight aluminum alloy plate. The plate surface is wholly oxidized through the anodizing treatment for electrical insulation. The opening rate of cathode plate hole is optimized through unit cell performance measurement of various opening rates. The performances are measured at room temperature and ambient pressure condition without any repulsive air supply. The active area of MEA is 10.08 $cm^2$ and active area per a unit cell is 1.68 $cm^2$. The peak power density is about 210 mW/$cm^2$ and the air-breathing planar stack of 2 Wis achieved as a small volume of 18 cc.

• 한국정보통신학회논문지
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• 제3권2호
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• pp.255-265
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• 1999

최근 정보통신 기술의 발달로 통신 시스템의 디지털화, 고속화, 소형 경량화 요구에 따라 통신기기 회로의 설계는 수동소자와 능동소자의 복합 형태를 나타내고 있으며, 정보 통신 기기에서 디지털 신호의 전송속도가 높아짐에 따라 선로의 종류와 특성에 따라 발생하는 누화(Crosstalk)와 상호 결합 등의 문제로 인하여 데이터의 손실 및 왜곡이 발생한다. 이런 문제점을 해석하기 위해서는 전송 선로를 등가적인 회로로 표현하는 것이 필요하며 중요하다. 본 논문에서는 전송 선로의 등가 파라미터를 계산하기 위해 모멘트법을 이용하여 단층 및 다층 구조의 마이크로 스트립 선로에 대한 해석 결과를 비교하여 나타낸다.

• Interdisciplinary Bio Central
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• 제2권2호
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• pp.1.1-1.8
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• 2010

Microdevices have been used as effective experimental tools for the rapid and multiplexed analysis of individual cells in single-cell assays. Technological advances for miniaturizing such systems and the optimization of delicate controls in micron-sized space homing cells have motivated many researchers from diverse fields (e.g., cancer research, stem cell research, therapeutic agent development, etc.) to employ microtools in their scientific research. Microtools allow high-throughput, multiplexed analysis of single cells, and they are not limited by the lack of large samples. These characteristics may significantly benefit the study of immune cells, where the number of cells available for testing is usually limited. In this review, I present an overview of several microtools that are currently available for single-cell analyses in two popular formats: microarrays and microfluidic microdevices. Then, I discuss the potential to study human immunology on the single-cell level, and I highlight several recent examples of immunoassays performed with single-cell microdevice assays. Finally, I discuss the outlook for the development of optimized assay platforms to study human immune cells. The development and application of microdevices for studies on single immune cells presents novel opportunities for the qualitative and quantitative characterization of immune cells and may lead to a comprehensive understanding of fundamental aspects of human immunology.