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메탈 더미 구조를 포함하는 서브 테라헤르츠 CMOS 온칩 마이크로스트립 패치 안테나
심동하(Dongha Shim),양지훈(Ji Hoon Yang),한승한(Seung Han Han),이현민(Hyounmin Lee),김기훈(Ki Hoon Kim),김호경(Hokyung Kim) 한국전자파학회 2017 한국전자파학회논문지 Vol.28 No.6
본 논문은 CMOS 공정에 수반되는 메탈 더미 구조가 서브 테라헤르츠 온칩 마이크로스트립 패치 안테나의 성능에 미치는 영향을 분석하였다. 45 ㎚ CMOS 공정을 이용해 400 ㎓ 온칩 안테나를 설계하고, 3D EM 시뮬레이션을 통하여 메탈 더미 구조의 밀도에 따른 안테나의 공진주파수와 효율을 분석하였다. 검증을 위해 발진기와 집적된 안테나를 설계/제작하고, FTIR과 볼로미터를 이용한 준광학적 방법을 통해 측정을 수행하였다. 측정 결과, 밀도가 27 %인 더미 구조에 의해 안테나의 복사전력이 417 ㎻에서 87 ㎻로 6.8 ㏈ 감소하는 것을 확인하였다. This paper analyzes the effect of metal dummy structures in CMOS on antenna performances of a sub-terahertz on-chip microstrip patch antenna. A 400-㎓ on-chip antenna is designed in a 45-㎚ CMOS process, and the resonance frequency and efficiency of the antenna are analyzed depending on the density of metal dummy structures. Antennas integrated with an oscillator are designed and fabricated for verification, and measurements are performed using quasi-optical methods with an FTIR and bolometer. The measurement results shows that the radiated power drops from 420 ㎻ to 90 ㎻ by 6.8 ㏈ due to the dummy structures with the density of 27 %.
UWB/WiFi 모듈 기반의 내시경 카메라용 무선전송 설계
심동하 ( Dongha Shim ),이재곤 ( Jaegon Lee ),이재선 ( Jaeson Yi ),차재상 ( Jaesang Cha ),강민구 ( Mingoo Kang ) 한국인터넷정보학회 2015 인터넷정보학회논문지 Vol.16 No.1
본 논문에서는 초광각 무선 내시경을 제안하고 구현하였다. 내시경은 초광각 카메라 모듈과 무선전송 모듈로 구성된다. 162도의 초광광 렌즈와 이미지 센서 및 카메라 프로세서가 3x3x9 cm3 크기의 케이스에 함께 패키지 된다. 무선전송 모듈로 UWB 기반 및 WiFi 기반의 플랫폼을 각각 구현한다. UWB 기반 모듈은 의 고화질 영상을 MJPEG로 압축하여, 2048x1536 (QXGA)의 해상도에서 15 fps의 속도로 영상을 전송하며, 최대 데이터 전송속도는 41.2 Mbps에 달한다. 구현된 내시경은 의료용 내시경의 화각과 해상도 수준을 가지며, 상용 고성능 WiFi 내시경과 비교할 때 ~3X의 화각과 16X의 해상도를 갖는다. WiFi 기반의 모듈은 640x480 (VGA)의 해상도에서 30 fps의 속도로 영상을 스마트 기기로 스트리밍 하며, 최대 1.5 Mbps의 데이터 전송속도를 보여준다. 구현된 모듈은 저가격의 의료용 무선 전자 내시경의 구현 가능성을 보여주며, U-헬스케어, 응급처치, 가정의료, 원격진료 등에 효과적으로 활용될 수 있을 것으로 기대된다. Ultra-wide-angle wireless endoscopes are demonstrated in this paper. The endoscope is composed of an ultra-wide-angle camera module and wireless transmission module. A lens unit with the ultra-wide FOV of 162 degrees is designed and manufactured. The lens , image sensor, and camera processor unit are packaged together in a 3x3x9-cm3 case. The wireless transmission modules are implemented based on UWB- and WiFi-based platform, respectively. The UWB-based module can transmit HD video to a computer in resolution of 2048x1536 (QXGA) and the frame rate of 15 fps in MJPEG compression mode. The maximum data transfer rate reaches 41.2 Mbps. The FOV and the resolution of the endoscope is comparable to a medical-grade endoscope. The FOV and resolution is ~3X and 16X higher than that of a commercial high-performance WiFi endoscope, respectively. The WiFi-based module streams out video to a smart device with th maximum date transfer rate of 1.5 Mbps at the resolution of 640x480 (VGA) and the frame rate of 30 fps in MJPEG compression mode. The implemented components show the feasibility of cheap medical-grade wireless electronic endoscopes, which can be effectively used in u-healthcare, emergency treatment, home-healthcare, remote diagnosis, etc.
심동하(Dongha Shim),김형오(Hyung-O Kim),이봉주(Bong-ju Lee),홍승철(Seung-Cheol Hong),이재선(Jason Lee),차재상(Jaesang Cha) 대한전기학회 2014 전기학회논문지 Vol.63 No.4
This paper proposes a wireless digital endoscope with a ultra-wide-angle view. Two key components are implemented to demonstrate the feasibility of the proposed endoscope. First, a ultra-wide-angle lens module with the field of view of 144 degree and F-number of 2.2 is designed and manufactured. Second, a wireless module for a high-speed video transfer is implemented using a USB device server and wireless LAN router. The wireless module can directly transfer a streaming video to a computer with the resolution of 1920x1080, frame rate of 30 fps, and data rate of 53.3 Mbps without an internet connection. Since the wireless module supports two USB devices, two spots can be simultaneously observed using the proposed endoscope.
대한민국 서해상 (인천-제주도)에서의 TVWS 가용채널 주파수 분석에 관한 연구
정찬형,차재상,심동하,Chung, Chanhyung,Cha, Jaesang,Shim, Dongha 한국항행학회 2022 韓國航行學會論文誌 Vol.26 No.5
This paper is the study in Korea to secure new frequency resources available at sea among terrestrial DTV (Digital TV) broadcasting bands. Focusing on Incheon and Jejudo in the west Sea of Korea, the possibility of using TVWS frequencies of DTV broadcast signals (channels 14-51, 470~698 MHz) was studied. According to the analysis, three channels, channel 19 (503 MHz), channel 37 (611 MHz) and channel 39 (623 MHz) can be used as TVWS available channels without interference with DTV in all nearby seas such as Incheon Port and Jeju Port. On the other hand, two channels, Channel 23 (527 MHz) and Channel 33 (587 MHz), were divided into strong DTV signals in the section between Incheon Port and Jeju Port, making it difficult to use them as available frequencies for TVWS on the west coast.
국내 도시철도 차량을 위한 FRACAS 기반의 신인성 관리 플랫폼 연구
장건(Geon Jang),정창우(Chang Woo Chung),심동하(Dongha Shim) 한국IT서비스학회 2020 한국IT서비스학회지 Vol.19 No.3
This paper describes a study on the FRACAS(Failure Reporting Analysis and Corrective Action System)-based dependability control platform for domestic urban railway trains. There are more demands for the verification of the dependability of trains as it becomes a regulation for train manufacturers to verify the dependability recently. Train manufacturers as well as railway operators need a effective FRACAS solution to perform the verification of the dependability. Yet current FRACAS solutions have limitations to support the verification processes effectively. This paper addresses the issues of current FRACAS solutions and suggests a FRACAS framework designed for the domestic urban railway trains. Service failure scenarios are standardized using the proposed availability model to implement a more user-friendly and reliable platform. A new FRACAS-based platform for the dependability control (SCARF??) has been developed to implement the suggested framework. The detail interfaces and functions of the platform are explained. The SCARF?? platform is expected to engage the increasing demands for the dependability control successfully enhancing the reliability, maintainability, availability and safety of domestic urban railway trains eventually.
정밀금형용 SKD61 강의 복합표면처리에 의한 표면신뢰성 향상
박민혁(Min-Hyeok Park),김동오(Dong-O Kim),엄정원(Joung-Won Eom),김진영(Jin-Yeong Kim),김유진(Yu-Jin Kim),김은우(Eun-Woo Kim),양원존(Won-Jon Yang),심동하(Dongha Shim),변재원(Jai-Won Byeon) 한국신뢰성학회 2022 신뢰성응용연구 Vol.22 No.2
Purpose: The lifespan of a die-casting steel mold depends on its surface hardness and wear resistance. Gas nitriding treatments for forming surface hardening layers have been widely applied to fabricate reliable die-casting molds. In the present study, we propose a complex surface treatment consisting of a micro-shot peening process and a sulfo-nitriding treatment to improve the surface hardness of SKD61 mold steel. Methods: The cross-sectional microstructure of the complex surface-treated SKD61 mold steel was observed using an optical microscope and a scanning electron microscope. The phase of the surface hardening layer was analyzed using an X-ray diffractometer. The micro-hardness and residual stress of the complex surface-treated SKD61 mold steel were evaluated as well. Results: The surface hardening layer consisted of the top-most compound layer and a diffusion layer. The micro-shot peening pretreatment increased the thickness of the compound layer. The general nitriding (GN) treatment led to the formation of the FexN compound layer, while the sulfo-nitriding (SN) treatment led to the formation of the FexN and FeS composite compound layer, which was thicker than the compound layer of the GN specimen. The hardness of GN and SN hardening layers improved by 125% and 135%, respectively, relative to that of the as-received SKD61 mold steel with a hardness of 450 HV. Conclusion: The SN treatment formed a reliable hardening layer with superior hardness than the GN treatment. Furthermore, the thicker sulfo-nitride compound layer produced by the SN treatment can further improve the lifespan of SKD61 steel molds.