• Smart Structures and Systems
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• 제1권2호
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• pp.159-184
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• 2005

The paper intends to summarize some guidelines for future smart structure system application in military aircraft. This preview of system integration is based upon a review on approximately one and a half decades of application oriented aerospace related smart structures research. Achievements in the area of structural health monitoring, adaptive shape, adaptive load bearing devices and active vibration control have been reached, potentials have been identified, several feasibility studies have been performed and some smart technologies have been already implemented. However the realization of anticipated visions and previously initial timescales announced have been rather too optimistic. The current development shall be based on a more realistic basis including more emphasis on fundamental aircraft strength, stiffness, static and dynamic load and stability requirements of aircraft and interdisciplinary integration requirements and improvements of integrated actors, actuator systems and control systems including micro controllers.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권8호
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• pp.340-346
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• 2002

Capacitor material utilized in the downsizing passive devices and integration of passive devices requires the physical and electrical properties at given area such as capacitor thickness reduction, relative dielectric constant increase, low leakage current and thermal stability. common capacitor materials, $Al_2O_3$, $SiO_2$, $Si_3N_4$, $SiO_2$/$Si_3N_4$, TaN and et al., used until recently have reached their physical limits in their application to integration of passive devices. $Ta_2O_{5}$ is known to be a good alternative to the existing materials for the capacitor application because of its high dielectric constant (25~35), low leakage current and high breakdown strength. Despite the numerous investigations of $Ta_2O_{5}$ material, there have little been established the clear understanding of the annealing effect on capacitance characteristic and conduction mechanism. This study presents the dielectric properties $Ta_2O_{5}$ MIM capacitor structure Processed by $O_2$ RTA oxidation. X-ray diffraction patterns showed the existence of amorphous phase in $600^{\circ}C$ annealing under the $O_2$ RTA and the formation of preferentially oriented-$Ta_2O_{5}$ in 650, $700^{\circ}C$ annealing and the AES depth profile showed $O_2$ RTA oxidation effect gives rise to the $O_2$ deficientd into the new layer. The leakage current density respectively, at 3~1l$\times$$10_{-2}$(kV/cm) were $10_{-3}$~$10_{-6}$(A/$\textrm{cm}^2$). In addition, behavior is stable irrespective of applied electric field. the frequency vs capacitance characteristic enhanced stability more then $Ta_2O_{5}$ thin films obtained by $O_2$ reactive sputtering. The capacitance vs voltage measurement that, Vfb(flat-band voltage) was increase dependance on the $O_2$ RTA oxidation temperature.

• 마이크로전자및패키징학회지
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• 제7권3호
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• pp.31-36
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• 2000

RF(radio Frequency)용 MCM(Multichip Module)-D 기판 내장형 인덕터를 개발하였다. MCM 기술은 고밀도 패키징 기술로서 주로 디지털회로에 많이 적용되어 왔으나, 최근에는 아날로그회로 및 디지털회로가 혼재된 혼성신호 및 초고주파 회로에도 적용되고 있다. 혼성신호에서는 능동소자 주변에 많은 수의 수동소자가 연결되므로 MCM-D 기판에 수동소자를 내장시키면 원가절감과 시스템의 크기 축소 및 경량화를 이를 수 있을 뿐 아니라, 성능과 신뢰성을 향상시킬 수 있다. 본 논문에서 MCM-D 기판은 Cu/감광성 BCB(Benzocyclobutene)를 각각 금속배선 및 절연막 재료로 사용하였고, 금속배선은 Ti/Cu를 각각 1000 $\AA$/3000 $\AA$으로 스퍼터한 후 fountain 방식으로 전기 도금하여 3 $\mu\textrm{m}$ Cu를 형성하였으며, 인덕터는 coplanar구조로 하여 기존의 반도체 공정을 이용하여 MCM-D기판에 인덕터를 안정적으로 내장시키고 전기적 특성을 측정하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.1673-1675
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• 2004

The design, modeling and measurement of RF switch module for GSM applications is presented in this paper. RF switch module is constructed using a LTCC multi-layer switching circuit and integrated low pass filter. Insertion and return loss of the low pass filter were designed less than 0.3 dB and better than 12.7 dB at 900 MHz. The RF switch module contained 10 embedded passives and 3 surface mount components integrated on $4.6{\times}4.8{\times}1.2$ mm, 6-layer multi-layer integrated circuit. The insertion loss of switch module was measured at 900 MHz was 11 dB.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 추계학술발표대회
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• pp.3.1-3.1
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• 2009

Nanotechnology has beenrapidly evolved from passive nanostructures where nanostructures with steadystructures and functions often used as parts of a product to activenanostructures which change their properties during use. Startingaround 2010, it is anticipated that researchers will cultivate expertise withsystems of nanostructures, directing large numbers of intricate components tospecified needs. One dimensional (1-D) nanostructures suchas nanowires and nanotubes are extremely attractive building blocks for nextgeneration devices because of their high surface to volume ratio and uniquesize dependent properties. In addition, their extremely high aspectratio offers researchers the potentials to build axial or radialheterostructures to integrate multiple functionality from intrinsic propertiesof the material or through interfacial phenomena. Spatialmanipulation and the ability to assemble and position nanostuructures in acontrolled matter so they are registered to define spaces is also a criticalstep toward scalable integration in high density nanodevices. In thispresentation, a generalized template directed electrodeposition with ancillaryassembly, contact will be presented to synthesize axial and radialheterostructures in cost-effective matter and these individual nanostructureswill be applied to spintronics, gas and biological sensors and thermoelectrics.

• Journal of Power Electronics
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• 제9권2호
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• pp.180-187
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• 2009

When converters operate in megahertz range, the passive components and magnetic devices generate high losses. However, the eddy current issues and choices of magnetic cores significantly affect on the design stage. Apart from that, the components' reduction, miniaturization technique and frequency scaling are required as well as improvement in thermal capability, integration technique, circuit topologies and PCB layout optimization. In transformer design, the winding and core losses give great attention to the design stage. From simulation work, it is found that E-25066 material manufactured by AVX could be the most suitable core for high frequency transformer design. By employing planar geometry topology, the material can generate significant power loss savings of more than 67% compared to other materials studied in this work. Furthermore, young researchers can use this information to develop new approaches based on concepts, issues and methodology in the design of magnetic components for high frequency applications.

• Carbon letters
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• 제13권1호
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• pp.17-22
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• 2012

Currently, graphene is a topic of very active research in fields from science to potential applications. For various radio-frequency (RF) circuit applications including low-noise amplifiers, the unique ambipolar nature of graphene field-effect transistors can be utilized for high-performance frequency multipliers, mixers and high-speed radiometers. Potential integration of graphene on Silicon substrates with complementary metal-oxide-semiconductor compatibility would also benefit future RF systems. The future success of the RF circuit applications depends on vertical and lateral scaling of graphene metal-oxide-semiconductor field-effect transistors to minimize parasitics and improve gate modulation efficiency in the channel. In this paper, we highlight recent progress in graphene materials, devices, and circuits for RF applications. For passive RF applications, we show its transparent electromagnetic shielding in Ku-band and transparent antenna, where its success depends on quality of materials. We also attempt to discuss future applications and challenges of graphene.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.912-915
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• 2004

Inductors material utilized in the downsizing passive devices and Rf components requires the physical and electrical properties at given area such as inductors thickness reduction, inductance and q-factor increase, low leakage current and thermal stability. In this study, Spiral inductors on the $SiO_2/Si$(100) substrate were fabricated by the magnetron sputtering method. Cu thin film with the thickness of $2{\mu}m$ was deposited on the substrate. Also we fabricated square inductors through the wet chemical etching technique. The inductors are completely specified by the turn width and the spacing between spirals. Both the width and spacing between spirals were varied from 10 to $60{\mu}m$ and from 20 to $70{\mu}m$, respectively. Inductance and Q factor dependent on the RF frequency were investigated to analyze performance of inductor arrays

• 한국광학회지
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• 제14권5호
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• pp.509-514
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• 2003

SOA(Semiconductor Optical Amplifier)를 단일 기판에 집적한 Mach-Zehnder 간섭계 구조의 파장변환기를 제작하여 40 nm 지역폭에 대한 10 Gb/s 파장변환 특성을 조사하였다. 제작된 파장변환기는 BRS(Buried Ridge Structure)형 SOA와 수동 도파로를 butt-joint결합하여 단일 집적한 구조이다. 집적화 과정에서 높은 도파 손실을 발생시키는 p+ InP덮개층을 제거하고 무첨가 InP로 도파로 덮개층 및 전류 차단층을 동시에 형성시키는 새로운 방법을 이용하였고, 모듈 제작에서 경사진 도파로와 광섬유를 효율적으로 광 접속하기 위하여 경사진 광섬유 배열을 제작하여 사용하였다. 이와 같이 제작된 파장변환기 모듈을 이용하여 1535-1575 nm의 40 nm 대역폭에서 1 ㏈ 이하의 power penalty를 갖는 10 Gb/s 파장변환을 구현하였고, 특히 negative penalty를 갖는 파장변환을 성공적으로 구현함으로써 2R(re-amplification, re-shaping) 기능을 제공할 수 있음을 보였다.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제7권12호
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• pp.295-300
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• 2018

최근 IT 기술의 급성장에 따라 종래의 많은 수동적인 업무가 자동화되었다. 이러한 자동화를 통해 많은 사람들의 여가 시간이 증대되고 이를 위한 다양한 서비스들이 개발되고 있다. 또한, 소형화되고 휴대에 편리한 스마트 디바이스의 등장으로 시간과 장소에 구애를 받지 않고 다양한 인터넷 서비스 이용이 가능하다. 많은 디바이스 및 서비스에서 발생되는 빅 데이터의 효율적인 저장 처리를 위해 가상화 기반의 다양한 연구들이 진행되고 있다. 이러한 연구 중에 온-프레미스 기반 분산된 데스크탑 자원을 통합하고 사용자에게 제공하는 데스크탑 스토리지 가상화는 가상화를 이용하여 분산된 레거시 데스크탑내에 사용되지 않는 자원을 통합한다. 이는 사용자에게 신뢰성 제공을 위한 고가용성이 매우 중요시된다. 또한, 분산된 데스크탑 기반 자원 통합 환경에서 효율적인 데이터 분배 저장 처리를 위한 계층적 구조 및 자원통합 연구들이 진행되고 있다. 그러나 온-프레미스 기반 자원 통합 환경에서 서버 고장 발생시 효율적인 대처를 위한 운영 연구가 미흡하다. 이러한 운영적 서버 고가용성을 위해 본 논문에서는 온-프레미스 기반 분산된 데스크탑내 스토리지 통합 환경에서 데스크탑 서버의 장애 발생에 따른 능동적인 대처가 가능한 무중단 서버 관리 기법을 제안한다. 이는 데스크탑 기반 통합 환경에서 데스크탑 추가 및 제거가 용이하다. 또한, 장애발생에 따라 대체 서버가 능동적으로 수행된다.