• Journal of Computing Science and Engineering
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• v.8 no.3
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• pp.129-136
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• 2014

This paper presents the equivalent circuit modelling and eigenfrequency analysis of a wideband robust capacitive radio frequency (RF) microelectromechanical system (MEMS) switch that was designed using Poly-Si and Au layer membrane for highly reliable switching operation. The circuit characterization includes the extraction of resistance, inductance, on and off state capacitance, and Q-factor. The first six eigenfrequencies are analyzed using a finite element modeler, and the equivalent modes are demonstrated. The switch is optimized for millimeter wave frequencies, which indicate excellent RF performance with isolation of more than 55 dB and a low insertion loss of 0.1 dB in the V-band. The designed switch actuates at 13.2 V. The R, L, C and Q-factor are simulated using Y-matrix data over a frequency sweep of 20-100 GHz. The proposed switch has various applications in satellite communication networks and can also be used for devices that will incorporate the upcoming IEEE Wi-Fi 802.11ad protocol.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.10
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• pp.32-39
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• 2009

Most mobile devices provide limited input interfaces in order to maximize the mobility and the portability. In this paper, the author proposes a small cubic-shaped tangible input interface which tracks the location, the direction, and the velocity using MEMS sensor technology to overcome the physical limitations of the poor input devices in mobile computing environments. As the preliminary phase for implementing the proposed tangible input interface, the prototype design and implementation methods are described in this paper. Various experiments such as menu manipulation, 3-dimensional contents control, and sensor data visualization have been performed in order to verify the validity of the proposed interface. The proposed tangible device enables direct and intuitive manipulation. It is obvious that the mobile computing will be more widespread and various kinds of new contents will emerge in near future. The proposed interface can be successfully employed for the new contents services that cannot be easily implemented because of the limitation of current input devices. It is also obvious that this kind of interface will be a critical component for future mobile communication environments. The proposed tangible interface will be further improved to be applied to various contents manipulation including 2D/3D games.

• Applied Chemistry for Engineering
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• v.32 no.4
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• pp.379-384
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• 2021

A microneedle is a tool that used for drug delivery and diagnosis. Unlike general injections, the microneedle is short in length, enabling effective drug delivery while minimizing pain and risk of infection. Conventionally, microneedles have been manufactured precisely at a nanometer level based on microelectro mechanical systems (MEMS) technology, requiring expensive equipments & maintenance and complicated processes. To address the issues, 3D printing research has been conducted to fabricate microneedles simply, economically, and rapidly. Since 3D printing facilitates to manufacture prototypes and apply feedbacks, it is advantageous for the development and commercialization of microneedle for pharmaceuticals and cosmetics. Therefore, this review will introduce stereolithography (SLA), two-photon polymerization (2PP), dynamic light processing (DLP), continuous liquid interface production (CLIP), and fused deposition modeling (FDM) 3D printing technologies and also highlight research trends for microneedle production using them. Furthermore, the limitation of the current microneedle technology and the direction to be solved in the future will be discussed.

• Journal of Advanced Navigation Technology
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• v.25 no.1
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• pp.68-77
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• 2021

In this paper, a GPS/MEMS IMU integrated navigation receiver module capable of operating in a high dynamic environment is designed and fabricated, and the results is confirmed. The designed module is composed of RF receiver unit, inertial measurement unit, signal processing unit, correlator, and navigation S/W. The RF receiver performs the functions of low noise amplification, frequency conversion, filtering, and automatic gain control. The inertial measurement unit collects measurement data from a MEMS class IMU applied with a 3-axis gyroscope, accelerometer, and geomagnetic sensor. In addition, it provides an interface to transmit to the navigation S/W. The signal processing unit and the correlator is implemented with FPGA logic to perform filtering and corrrelation value calculation. Navigation S/W is implemented using the internal CPU of the FPGA. The size of the manufactured module is 95.0×85.0×.12.5mm, the weight is 110g, and the navigation accuracy performance within the specification is confirmed in an environment of 1200m/s and acceleration of 10g.

• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.3
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• pp.169-174
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• 2006

In this work, we demonstrate a novel compact mechanical beam steering transmitter based on a direct vertical integration of a 2-D MEMS-based mechanical beam steering antenna with a VCO on a single silicon platform. By eliminating the long feed lines and waveguide metal blocks, the radiation pattern has been improved vastly, resulting in an almost ideal pattern at every scan angle. The losses incurred by the feed lines and phase shifters are also eliminated, which allows the transmitter to be implemented using only a single VCO. The system complexity has been greatly reduced with a total module size of only 1.5 cm ${\times}$ 1.5 cm ${\times}$ 0.4 cm. This work demonstrates that RF MEMS can be a key enabling technology for high-level integration.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1452-1453
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• 2008

본 논문에서는 RF MEMS 패키징 플랫폼을 활용한 안테나 구조를 제안하고, 이를 바탕으로 마이크로머시닝 공정을 이용한 슬롯 결합형 원형 패치 안테나를 제작하였다. 제안된 안테나는 RF MEMS 패키징 플랫폼 상에서 패키징 물질을 안테나의 유전 물질로 이용하기 위하여 슬롯 결합형 급전 구조를 사용하였다. 한편, BCB를 이용한 폴리머 접착 접합 공정의 RF MEMS 패키징 플랫폼을 기반으로, 하판 유리기판과 상판 수정 기판을 일체화한 형태로 마이크로 스트립라인 안테나를 제작하였다. 최종 제작된 안테나는 20.36-GHz에서 -21 dB의 반사 손실 값을 나타내며, 1.7-GHz, 즉 8.3 %의 주파수 대역을 가진다.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.595-596
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• 2006

A novel Si via structure is suggested and fabricated for 3D MEMS package using the doped silicon as an interconnection material. Oxide isolations which define Si via are formed simultaneously when fabricating the MEMS structure by using DRIE and oxidation. Silicon Direct Bonding Multi-stacking process is used for stacked package, which consists of a substrate, MEMS structure layer and a cover layer. The bonded wafers are thinned by lapping and polishing. A via with the size of $20{\mu}m$ is fabricated and the electrical and mechanical characteristics of via are under testing.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.623-626
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• 2005

In this paper, we proposed a new type SIR bandpass filter using DAML. This filter is consisted of 2 layers with MEMS resonator layer and CPW feed line. DAML ring resonator is elevated with $10\;{\mu}m$ height from GaAs substrate. Using MEMS processing, we are able to realize SIR bandpass filter easily. Furthermore it is useful to integrate on conventional MMICs because it has CPW interfaces and ring resonator is isolated from substrate by air-gap. We optimized and measured the results that $S_{21}$ attenuation at rejected band is over 15 dB, insertion loss is inside the limit of 3 dB, and relative bandwidth is about 10 % at 60 GHz

• Journal of Sensor Science and Technology
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• v.16 no.1
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• pp.62-67
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• 2007

This paper presents a novel MEMS condenser microphone with rigid backplate to enhance acoustic characteristics. The MEMS condenser microphone consists of membrane and backplate chips which are bonded together by gold-tin (Au/Sn) eutectic solder bonding. The membrane chip has 2.5 mm${\times}$2.5 mm, $0.5{\mu}m$ thick low stress silicon nitride membrane, 2 mm${\times}$2 mm Au/Ni/Cr membrane electrode, and $3{\mu}m$ thick Au/Sn layer. The backplate chip has 2 mm${\times}$2 mm, $150{\mu}m$ thick single crystal silicon rigid backplate, 1.8 mm${\times}$1.8 mm backplate electrode, and air gap, which is fabricated by bulk micromachining and silicon deep reactive ion etching. Slots and $50-60{\mu}m$ radius circular acoustic holes to reduce air damping are also formed in the backplate chip. The fabricated microphone sensitivity is $39.8{\mu}V/Pa$ (-88 dB re. 1 V/Pa) at 1 kHz and 28 V polarization voltage. The microphone shows flat frequency response within 1 dB between 20 Hz and 5 kHz.

• The Optical Journal
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• s.128
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• pp.38-41
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• 2010

HMD(Head mounted Display)는 보안경이나 헬멧 형태로 눈앞의 지근거리에 초점이 형성된 가상스크린을 보는 안경형 모니터 장치로서 예전에는 군사용 시뮬레이션이나 가상현실(VR-Virtual Reality)을 실현하기 위해 개발되었으며, 양쪽 눈의 근접한 유치에 설치된 1인치 이하의 LCD, OLED, MEMS panel 등 마이크로 디스플레이에서 발생되는 이미지를 광학시스템을 통해 확대하여 대형 가상화면을 형성한다. IT 산업의 비약적인 발전에 힘입어 휴대용 동영상 및 모바일 정보검색, 3D의 시대가 대두됨에 따라 휴대폰이나 PMP의 작은 화면으로는 만족하지 못하는 소비자의 수요에 적합한 개인 휴대용 모니터 장치로, 3D를 구현하는 안경형 모니터로서 향후 크게 형성될 모바일 산업의 핵심제품이 될 전망이다.