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Novel MMIC protection technique in plasma etching process for mechanically movable RF mems antenna
Kim, Jung-Mu,Lee, Sanghyo,Kim, Yongsung,Kim, Jong-Man,Cheon, Changyul,Kwon, Youngwoo,Kim, Yong-Kweon Wiley Subscription Services, Inc., A Wiley Company 2008 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS - Vol.50 No.12
<P>In this article, we proposed the novel monolithic microwave integrated circuit (MMIC) protection technique in plasma etching process for MMIC mounted mechanically movable RF MEMS antenna. We could eliminate the distortion of radiation pattern caused by RF feed line on antenna frame and torsional hinge as using MMIC direct mounting on antenna plate instead of using external RF power source. Silicon-based mechanically movable RF MEMS antenna was released using DRIE process, which was performed on the backside of silicon substrate after MMIC mounting on RF MEMS antenna plate. An aluminum layer on the front side of RF MEMS antenna plays a role of etch stop layer for DRIE process. We measured the radiation pattern as rotating the moving plate along the vertical- and horizontal-direction hinge mechanically. We could obtain the radiation pattern without gain reduction and distortion of radiation pattern. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 3089–3093, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23870</P>
Silicon MEMS probe using a simple adhesive bonding process for permittivity measurement
Kim, Jung-Mu,Oh, Dong Hoon,Yoon, Jeonghoon,Cho, Sungjoon,Kim, Namgon,Cho, Jeiwon,Kwon, Youngwoo,Cheon, Changyul,Kim, Yong-Kweon IOP 2005 Journal of micromechanics and microengineering Vol.15 No.11
<P>We developed a silicon MEMS probe for permittivity measurements using an adhesive bonding process. Only two photolithographic masks are required to fabricate the probe, which can be implemented through simple bonding processes using silicon substrates and a benzo cyclo butene (BCB) adhesive layer. Undoped silicon substrates with thicknesses of 300 ?m are used as the dielectric layers of the proposed probe. BCB layers, which have good electrical properties at high frequencies as well as adhesive properties for the bonding process, play the role of bonding materials between the two silicon substrates. The length of the probe is 30 mm, and the aperture located at the tip of the probe is 1.1 mm ? 0.62 mm. The permittivity of 0.5% saline was measured, and the results agreed with the values obtained through the Cole–Cole equation. To validate the feasibility of this probe for practical biological applications, we also performed <I>in vivo</I> measurements of the muscle, skin and blood of mice. Due to the simple fabrication process, the cost of the probe can be reduced in comparison with the previous micromachined probe (<A article='0960-1317/15/3/015'>Kim <I>et al</I> 2005 <I>J. Micromech. Microeng.</I> <B>15</B> 543–50</A>) as well as the conventional laser machined probe. Low cost leads to disposability, which is an important factor for practical biomedical applications; and thus, coupled with the probe's capabilities of MMIC integration and CMOS compatibility, this probe has excellent potential in the field of microwave permittivity measurements.</P>
김석권(Kim, Seokkwon),김동현(Kim, Dong Hyun),이성희(Lee, Sung Hee),권순호(Kwon, Soon Ho),마진아(Ma, Jin A),이선익(Sun Ik, Lee),오창열(Oh, ChangYul) 한국항공우주연구원 2013 항공우주산업기술동향 Vol.11 No.1
다중대역 안테나 시스템은 이중 또는 삼중 대역의 동작주파수에 따라 운용 가능한 시스템으로서 우주항공용 원격측정 및 위성통신 등의 분야에서 활발히 연구개발 중이다. 다중대역 안테나 시스템은 다중대역 피드와 주파수 선택막(Frequency selective surface, FSS)을 이용하여 구현할 수 있다. 본 논문에서는 교차다이폴의 배열을 이용한 UHF 및 L/S 다중대역 피드, 동심공동 동축도파관을 이용한 L/S/C 다중대역 피드, 동축 혼을 이용한 X/Ka, S/X, S/Ka 다중대역 피드 및 코러게이트 혼을 이용한 X/Ka 다중대역 피드 등에 관한 기술동향을 파악하였다. 또한, FSS와 X/Ka 다중대역 피드를 결합한 X/Ku/Ka 다중대역 안테나 시스템을 알아보았다. Multi-band antenna systems support dual or triple frequency bands, and this system has been intensively researched and developed for aeronautical telemetry and satellite communication areas. It is widely known that multi-band antenna systems can be implemented by a multi-band antenna feed and/or frequency selective surface(FSS). In this paper, we survey multi-band feeds using array of crossed-dipoles for UHF and L/S bands, concentric cavity coaxial waveguide for L/S/C bands, the coaxial horn for X/Ka, S/X and S/Ka bands, and the corrugated horn for X/Ka bands. Moreover, X/Ku/Ka multi-band system with FSS is introduced, where Ku single-band feed and X/Ka dual-band feed are employed.
면역독성평가 대체시험법 개발을 위한 참조 시험물질 선정 방안
김창열 ( Changyul Kim ),허용 ( Yong Heo ) 한국동물실험대체법학회 2021 동물실험대체법학회지 Vol.15 No.1
Alternative test method for screening immunotoxic substances has not been actively challenged and no test guideline has been officialized internationally. Preparation of master list on reference chemicals is a critical process for decision on positive or negative immunotoxicity of test substances through alternative test method. The reference master list is recommended to include various scopes of immuntoxic xenobiotics including medicinal products, cosmetic ingredients, and industrial or environmental agents. Data bases or research results on human or animal immunotoxicity of chemicals were collected and analyzed for preparing the list of reference chemicals. Twenty eight chemicals were selected as non-immunotoxicants, which could be used as negative controls for immunotoxicity and 10 immunosuppressive drugs were chosen for classifying immunosuppressive toxicity of test substances. Considering chemicals used as positive controls for immunotoxicity, 38 substances with aberrant immune regulatory capacity were listed, which are categorized into 23 industrial or environmental agents, 12 medicinal products, and 3 agrochemicals. The list of reference test substances could contribute to development of in vitro alternative assay method for immunotoxicity evaluation.
폴리에틸렌 미세플라스틱의 임신 마우스 위내 투여 및 기도 점적에 따른 신생자 간독성 평가
김근우(GeunWoo Kim),김창열(ChangYul Kim) 한국환경보건학회 2022 한국환경보건학회지 Vol.48 No.2
Background: Current research suggests that humans are exposed to microplastics through consumption of foods and beverages, the airway route, and a variety of other means. Objectives: We evaluated oxidative stress and inflammation from polyethylene microplastics (PE-MPs) in the neonatal liver through intragastric administration or intratracheal instillation in pregnant mice. Methods: PE-MPs were administered from gestational day 9 to postnatal day 7. The intragastric administration group (0.01 mg/mouse/day or 0.1 mg/mouse/day) and intratracheal instillation group (6 μg/mouse/day or 60 μg/mouse/day) of PE-MPs were administered. After sacrifice, the oxidative stress and inflammation of the neonatal livers were measured. Results: As a result of the oxidative stress caused by PE-MPs in the neonatal livers, glutathione peroxidase decreased in a concentration-dependent manner in the intragastric administration group compared to the control group and intratracheal instillation decreased in high concentration PE-MPs. The catalase level increased at high concentrations of intragastric administration and intratracheal instillation. To confirm the level of inflammation caused by PE-MPs, monocyte chemoattractant protein-1 and tumor necrosis factor- alpha were increased compared to the control group except for intratracheal intilation-high concentration PE- MPs. The C-reactive protein level was decreased by intragastric administration compared to the control group and intratracheal instillation was increased compared to the control group. Conclusions: Despite the difficulty in comparing the toxic intensity between intragastric administration and intratracheal instillation of PE-MPs, our study revealed that oxidative stress and inflammation were induced in the neonatal liver. However, it is necessary to evaluate the toxic effects of microplastics on various organs as well. Overall, the present study indicates that the evaluation of toxic effects of long-term microplastic exposure, potential of microplastic toxicity on next-generation offspring and toxicity mechanism in human should be considered for further investigations.