Capstone Design Project by Team Activities

심준환 한국공학교육학회 2010 공학교육연구 Vol.13 No.2

This paper deals with the introduction of capstone design project by team activities in Department of Electronics andCommunication Engineering, Korea Maritime University. This course is referred to as Creative Engineering Design for spring semester of 4th-year undergraduates. The course focuses on creative thinking and cooperative mind to students bylearning engineering design skills, realizing their idea through design project and recognizing practicality of their systems.The intent of the course is to provide a true “capstone” experience, where students can combine their skills to achieve thesuccessful completion of a project. This paper describes class process and evaluation method, and cooperative works withmentees and industrial mentors connected through Hanium network for IT mentoring activities.

Gas-Flow Sensor using Optical Fiber Bragg Grating(FBG)

심준환,조석제,유영호,손경락 한국항해항만학회 2008 한국항해항만학회지 Vol.32 No.9

We have proposed and demonstrated an gas-flow sensor using optical fiber bragg grating(FBG). The flow sensor has no electronics and no mechanical parts in its sensing part and the structure is thus simple and immune to electromagnetic interference(EMI). The FBG sensor was consisted of the sensing element and a coil heater. The metal coil was used to supply the current to the FBG. While some currents supply to the coil, the refractive index of the FBG under the coil is changed and thus the wavelength shift of fiber optic sensor was induced. In this work, the wavelength shift according to flow-rate was experimentally studied and was used to evaluate the gas flow-rate in a gas tube. As a result, it was possible to measure the flow-rate in a linear range from 5 to 20 ℓ/min with a resolution of approximately 1ℓ/min at the applied currents of 100 ㎃ and 120 ㎃. The measured sensitivities were 15.3 pm/ℓ/min for 100 ㎃ and 20.2 pm/ℓ/min for 120 ㎃. We have proposed and demonstrated an gas-flow sensor using optical fiber bragg grating(FBG). The flow sensor has no electronics and no mechanical parts in its sensing part and the structure is thus simple and immune to electromagnetic interference(EMI). The FBG sensor was consisted of the sensing element and a coil heater. The metal coil was used to supply the current to the FBG. While some currents supply to the coil, the refractive index of the FBG under the coil is changed and thus the wavelength shift of fiber optic sensor was induced. In this work, the wavelength shift according to flow-rate was experimentally studied and was used to evaluate the gas flow-rate in a gas tube. As a result, it was possible to measure the flow-rate in a linear range from 5 to 20 ℓ/min with a resolution of approximately 1ℓ/min at the applied currents of 100 ㎃ and 120 ㎃. The measured sensitivities were 15.3 pm/ℓ/min for 100 ㎃ and 20.2 pm/ℓ/min for 120 ㎃.

Capstone Design Projects based on Invention Education

심준환 한국공학교육학회 2012 공학교육연구 Vol.15 No.4

This paper deals with the introduction of capstone design projects based on invention education in Department of Electronics and Communication Engineering, Korea Maritime University. This course is referred to as Creative Engineering Design for spring semester of 4th-year undergraduates. The course focuses on creative thinking and cooperative mind to students by learning engineering design skills, realizing their idea through design project and recognizing practicality of their systems. To improve creative thinking of students, intellectual property (IP) education is very helpful. If engineering students take training program in IP, it will be very beneficial for CEOs to manage intellectual capital in many industries and to ensure competition power in their business. This study suggested that students take interest in connecting their ideas with inventions through invention education reinforcing an invention and a patent exercise. It is expected that this study may help to develop new curriculum of capstone design project including IP education in many universities.

Length Effects of Hetero-Core Optical Biosensor based on Evanescent Field Absorption

심준환,손경락,찬주광 한국항해항만학회 2008 한국항해항만학회지 Vol.32 No.9

Sensing performances of evanescent field absorption (EFA) hetero-core fiber sensor has been presented based on EFA by changing the length and the core diameter of the single mode fiber. Experimental results have demonstrated a good feature in their relationship between the length and the core diameter of the single mode fiber. The sensor consists of 2 fiber optics which have the same cladding diameter of 125 ㎛. However one fiber optic used is single mode and has varying core diameter ranging from 3.3 to 5.6 ㎛. The other fiber is multimode type and has a thicker fixed core diameter of 62.5 ㎛. The 2 fiber optics are thermally spliced together. Experiments conducted to measure the resonance wavelength were carried out over a range of refractive index, to find the optimum sensing length. Experiments show that core diameter of the single mode fiber and sensing length affects the linearity and sensitivity. Sensing performances of evanescent field absorption (EFA) hetero-core fiber sensor has been presented based on EFA by changing the length and the core diameter of the single mode fiber. Experimental results have demonstrated a good feature in their relationship between the length and the core diameter of the single mode fiber. The sensor consists of 2 fiber optics which have the same cladding diameter of 125 ㎛. However one fiber optic used is single mode and has varying core diameter ranging from 3.3 to 5.6 ㎛. The other fiber is multimode type and has a thicker fixed core diameter of 62.5 ㎛. The 2 fiber optics are thermally spliced together. Experiments conducted to measure the resonance wavelength were carried out over a range of refractive index, to find the optimum sensing length. Experiments show that core diameter of the single mode fiber and sensing length affects the linearity and sensitivity.

산화된 다공질 실리콘 기판 위에 제작된 MMIC용 Air-Bridge Interconnected Coplanar Waveguides

심준환,이해영,이종현,權載祐,朴正用,李東仁,金鎭良 대한전자공학회 2002 電子工學會論文誌-SD (Semiconductor and devices) Vol.39 No.4

In this paper, to improve the characteristics of a transmission line on silicon substrate, we fabricated air-bridge interconnected CPW transmission line on a 10-㎛-thick oxidized porous silicon(OPS) substrate using surface micromachining. Air-bridge interconnected CPW of S-W-S = 30-80-30 ㎛ has insertion loss of -0.25 ㏈ and return loss of -28.9 ㏈ at 4 ㎓. And return loss of CPW with stepped compensated air-bridge(S-W-S = 30-100-30 ㎛) is improved -0.98 ㏈ at 4 ㎓. The results indicate that the thick OPS provides an approach to incorporate high performance, low cost microwave and millimeter wave circuits in a high-resistivity silicon-based process. 본 논문에서는 실리콘 기판상의 전송선로 특성을 개선하기 위하여 표면 마이크로머시닝 기술을 이용하여 10 ㎛ 두께의 다공질 실리콘 산화막으로 제조된 기판 위에 air-bridge interconnect된 CPW 전송선로를 제작하였다. 간격이 30 ㎛, 신호선이 80 ㎛인 CPW air-bridge 전송선의 삽입손실은 4 ㎓에서 -0.25 ㏈이며, 반사손실은 -28.9 ㏈를 나타내었다. S-W-S = 30-100-30 ㎛인 stepped compensated air-bridge를 가진 CPW는 손실이 4 ㎓일 때, -0.98 ㏈ 개선됨을 알 수 있었다. 이와 같은 결과로부터 두꺼운 다공질 실리콘은 고 저항 실리콘 집적회로 공정에서 고성능, 저가의 마이크로파 및 밀리미터파 회로 응용에 충분히 활용 될 수 있으리라 기대된다.

순차적으로 전압 인가된 RF MEMS 스위치를 이용한 재구성 슬롯 안테나의 설계

심준환,윤동식,박동국,강인호,Jung-Chih Chiao 한국항해항만학회 2004 한국항해항만학회지 Vol.28 No.5

본 논문은 순차적으로 전압 인가된 RF MEMS 스위치를 이용하여 재구성 슬롯 안테나를 설계하였다. MEMS 수위치의 구동전압과 최대 스트레스를 구하기 위하여, 에어갭 높이에 따른 스위치의 특성을 ANSYS 시뮬레이션으로 분석하였다. MEMS 스위치의 구동전압은 하부 전극과 상부 스위치 사이의 에어갭 높이의 스위치 형상에 의해 결정된다. 설계된 MEMS 스위치의 길이는 각각 240 ㎛, 320 ㎛, 400 ㎛ 이고, 에어갭은 6 ㎛이었다. 설계된 슬롯 안테나는 전체크기가 10㎜×10㎜이며, 슬롯의 크기는 길이가 500 ㎛, 폭이 200 ㎛이었다. 그리고 CPW 급전선은 전체의 길이는 5 ㎜이며, 입구에서의 CPW는 30-80-30 ㎛이고, 슬롯에서의 CPW는 150-300-150 ㎛이다. 제안된 소자의 공진주파수의 튜닝은 RF MEMS 스위치에 DC 바이어스를 인가함으로 안테나의 전기적인 길이를 변화시켜 이루어진다. 설계된 슬롯 안테나를 시뮬레이션, 제조 및 측정을 하였다. In this paper, we designed a reconfigurable slot antenna using sequentially voltage-applied RF MEMS switches. In order to obtain pull-in voltage and maximum stress of the MEMS switches, the switch structures in accordance with airgap height was analyzed by ANSYS simulation. A actuation voltage of MEMS switches can be determined by switch geometry and airgap height between a movable plate and a bottom plate. The designed lengths of MEMS switches were 240 ㎛, 320 ㎛, 400 ㎛, respectively and the airgap was 6 ㎛. The total size of the designed slot antenna was 10㎜×10㎜ and the slot length and width were 500 ㎛ and 200 ㎛, respectively. the length and size of the CPW feedline were 5 ㎜ and 30-80-30 ㎛, respectively. and the size of the CPW in the slot was 150-300-150 ㎛. The tuning of the resonant frequency of the proposed device is realized by varying the electrical length of the antenna, which is controlled by applying the DC bias voltages to the RF MEMS switches. The designed slot antenna has simulated fabricated and measured.

AUSA에서 무엇을 배우나–1989 미 육군협회 연차총회 및 병기전시회를 중심으로

심준환,Sim, Jun-Hwan 한국방위산업진흥회 1990 國防과 技術 Vol.- No.135

현재 AUSA의 군인 및 민간인등 개인회원은 15만명 이상이며, 찬조회원인 업체는 3천6백개사에 이른다. 개인회원은 강제가 아닌 임의이지만, 군사학교나 군부대에서는 장교, 하사관, 사병 및 각 후보생에게 입회를 권장하고 있다. AUSA는 학술연구, 홍보 및 병기의 전시 이외에도 복리후생업무도 취급하고 있다. 요금이 낮은 보험, 디스카운트 물자의 알선등이 그 일례이다. 해군, 해병대, 공군에도 AUSA와 유사한 사업을 하는 단체가 있다

선택적인 다공질 실리콘 에칭법을 이용한 압저항형 실리콘가속도 센서의 제조

심준환,김동기,조찬섭,태흥식,함성호,이종현 ( Jun Hwan Sim,Dong Ki Kim,Chan Seob Cho,Heung Sik Tae,Sung Ho Hahm,Jong Hyun Lee ) 한국센서학회 1996 센서학회지 Vol.5 No.5

A piezoresistive silicon acceleration sensor with 8 beams, utilized by an unique silicon micromachining technique using porous silicon etching method which was fabricated on the selectively diffused (111)-oriented n/n/n silicon subtrates. The width, length, and thickness of the beam was 100 ㎛, 500 ㎛, and 7 ㎛, respectively, and the diameter of the mass paddle (the region suspended by the eight beams) was 1.4 mm. The seismic mass on the mass paddle was formed about 2 mg so as to measure accelerations of the range of 50g for automotive applications. For the formation of the mass, the solder mass was loaded on the mass paddle by dispensing Pb/Sn/Ag solder paste. After the solder paste is deposited, Heat treatment was carried out on the 3-zone reflow equipment. The decay time of the output signal to impulse excitation of the fabricated sensor was observed for approximately 30 ms. The sensitivity measured through summing circuit was 2.9 mV/g and the nonlinearity of the sensor was less than 2% of the full scale output. The output deviation of each bridge was ±4%. The cross-axis sensitivity was within 4% and the resonant frequency was found to be 2.15 kHz from the FEM simulation results.

합산회로를 통하여 타축감도가 자체상쇄된 6빔 가속도센서의 제조

심준환,김동권,이종현 대한전자공학회 1998 電子工學會論文誌, D Vol.d35 No.2

A six-beam accelerometer with self-compensated off-axis sensitivity was fabricated onthe selectively diffused (111)-oriented n/n$^{+}$/n silicon substrates by a unique porous silicon micromachining technique, which has self-stip characteristics and highly seletive formation of porous silicon layer during anodic reaction. Also, the characteristics of the fabricated accelerometer were investigated. The sensitivity of the acceleormeter added up outputs of three bridges through a summing circuit was 0.68 mV/g and the nonlinearity was less than 2% of the full scale output. The measured first resonant frequency was 4.236 kHz. When the outputs of three bridges were compared to summing output of bridges obtained through summing circuit, the normal output for Z-axis acceleration exhibited the same value s summing outputs of three bridges without reduction of sensitivity and thus the sensitivity decrease due to additional beam was compensated. Although a maximum off-axis sensitivity in one bridge of the accelerometer showed 17% of normal sensitivity, the off axis sensitivity obtained from summing output of three bridges decreased to 1.0%. Therefore, the self-elimination of off-axis sensitivity can be simply realized by obtaining the output of the sensor through summing circuit.t.

III-V 화합물 반도체 마이크로머시닝을 위한 InP를 기반으로 한 미세구조의 제조에 관한 연구

심준환,노기영,이종현,황상구,홍창희 한국정보통신학회 2000 한국정보통신학회논문지 Vol.4 No.5

본 논문에서는 III-V 화합물 반도체 마이크로머시닝을 위한 InP를 기반으로한 미세구조의 제조에 관하여 보고한다. InP/InGaAsP/InP 구조를 성장시키기 위하여 수직 LPE 시스템을 사용하였다. 성장된 InGaAsP층의 두께는 $0.4\mum$이고, InP top-layer의 두께는 $1\mum$이었다. InGaAsP 미세구조의 제조는 front-side 벌크 마이크로 머시닝으로 이루어졌다. 실험결과에서 <100> 방향으로 놓인 빔의 에칭이<110>와 <110> 방향에서의 에칭보다 더 빠르기 때문에 빔은 <100> 방향으로 정렬되어야 함을 보였다. In this paper, we report a fabrication of InP-based microstructurs for III-V compound semiconductor micromachining. Vertical liquid phase epitaxy(LPE) system was used in order to grow the InP/lnGaAsP/InP layers. The thicknesses of InP top-layer and InGaAsP were $1\mum \;and \;0.4\mum$, respectively. The fabrication of InGaAsP microstructures involves front-side bulk micromachining. The experimental result showed the beams must be carefully aligned in the <100> direction since the etching of the beam in the <100> direction is more faster than that of the beam in the <110> and <110> direction.