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A 18 GHz Broadband Stacked FET Power Amplifier Using 130 nm Metamorphic HEMTs
Choonghee Lee,Youngmin Kim,Yumin Koh,Jihoon Kim,Kwangseok Seo,Jinho Jeong,Youngwoo Kwon IEEE 2009 IEEE microwave and wireless components letters Vol.19 No.12
<P>A broadband power amplifier (PA) with a 3 dB power bandwidth of 72% is presented using metamorphic high electron mobility transistors (mHEMTs). A stacked FET structure, where transistors are series connected to combine voltage swings, is employed to overcome relatively low breakdown voltages of mHEMTs. Series-connected PA's show much higher load impedance compared to the parallel combined transistors, which allows output matching to be realized in the low quality (Q)-factor region, providing the broadband performance. The fabricated PA using quadruple-stacked 130 nm mHEMTs has a gain of 21.2 dB and saturated output power of 26.4 dBm with power added efficiency (PAE) of 33% at the design frequency of 18 GHz. The 3 dB output power bandwidth is from 10 to 23 GHz.</P>
소스 피드백을 이용한 고이득 W-band MMIC 증폭기 설계
박상민(Sangmin Park),김영민(Youngmin Kim),고유민(Yumin Koh),서광석(Kwang-Seok Seo),권영우(Youngwoo Kwon),정진호(Jinho Jeong) 大韓電子工學會 2010 電子工學會論文誌-TC (Telecommunications) Vol.47 No.10
본 논문에서는 70 ㎚ mHEMT MMIC 기술을 이용한 고이득 W-band 증폭기를 제시한다. W-band에서 고이득 특성을 얻기 위하여 공통 소스 FET의 소스 피드백 라인의 길이를 조절하면 설계 주파수에서 이득이 최대가 되도록 하였다. 이 라인의 길이를 조절하여 94 ㎓에서 MAG를 0.8 ㏈ 향상 시킬 수 있음을 시뮬레이션에서 확인하였다. 뿐만 아니라, 이 소스 피드백 라인은 FET의 입력 임피던스도 변화시켜 입력 정합을 용이하게 한다. 이 현상을 이용하여 공통 소스 FET 4단으로 이루어진 W-band 증폭기를 CPW로 설계하였다. 제작된 W-band 증폭기는 측정 결과 70∼103 ㎓에서 22.0 ㏈ 이상의 아주 우수한 이득 특성을 보였다. In this paper, a high gain W-band amplifier is presented using 70 ㎚ mHEMT MMIC technology. The length of source feedback line of common-source FET is carefully determined to maximize the gain at a design frequency. Simulation shows that MAG can be increased by 0.8 ㏈ by optimizing the length of this line. In addition, this feedback line changes the input impedance of the common-source FET in a way that the input match can be made easier. In this work, 4-stage amplifier is designed on CPW using the source feedback. The measurement shows the excellent gain performance higher than 22.0 ㏈ across 70∼103 ㎓.
Liao, Qiaogan,Yang, Kun,Chen, Jianhua,Koh, Chang Woo,Tang, Yumin,Su, Mengyao,Wang, Yang,Yang, Yinhua,Feng, Xiyuan,He, Zhubing,Woo, Han Young,Guo, Xugang American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.34
<P>Halogenated solvents are prevailingly used in the fabrication of nonfullerene organic solar cells (NF-OSCs) at the current stage, imposing significant restraints on their practical applications. By copolymerizing phthalimide or thieno[3,4-<I>c</I>]pyrrole-4,6-dione (TPD) with 1,4-di(3-alkoxy-2-thienyl)-2,5-difluorophenylene (DOTFP), which features intramolecular noncovalent interactions, the backbone planarity of the resulting DOTFP-based polymers can be effectively tuned, yielding distinct solubilities, aggregation characters, and chain packing properties. Polymer DOTFP-PhI with a more twisted backbone showed a lower degree of aggregation in solution but an increased film crystallinity than polymer DOTFP-TPD. An organic thin-film transistor and NF-OSC based on DOTFP-PhI, processed with a nonhalogenated solvent, exhibited a high hole mobility up to 1.20 cm<SUP>2</SUP> V<SUP>-1</SUP> s<SUP>-1</SUP> and a promising power conversion efficiency up to 10.65%, respectively. The results demonstrate that DOTFP is a promising building block for constructing wide bandgap polymers and backbone coplanarity tuning is an effective strategy to develop high-performance organic semiconductors processable with a nonhalogenated solvent.</P> [FIG OMISSION]</BR>
Spatial Profiling of Non-small Cell Lung Cancer: Unveiling Tumorigenesis and Immunotherapy Response
( Joon Kim ),( Seung Hyun Yong ),( Gyuho Jang ),( Yumin Kim ),( Raekil Park ),( Hyun-hee Koh ),( Sehui Kim ),( Chang-myung Oh ),( Sang Hoon Lee ) 대한결핵 및 호흡기학회 2023 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.136 No.0
Youngrak Park,Siyoung Lee,Kwangseok Seo,Youngwoo Kwon,Youngmin Kim,Yumin Koh 한국전자파학회JEES 2009 Journal of Electromagnetic Engineering and Science Vol.9 No.4
In this paper, we present a CPW-based 77 ㎓ 3-stage power amplifier MMIC for automotive radar systems. The power amplifier MMIC has been realized using a 130 ㎚ In0.88GaP/In0.4AlAs/In0.4GaAs metamorphic high-electron mobility transistors(mHEMTs) technology and an output stage with a cascode configuration. This produced a good output power and gain performance at 77 ㎓. The fabricated power amplifier MMIC exhibited a small-signal gain of 18 ㏈, an output power of 17 ㏈m and 9 % power added efficiency(PAE) at 77 ㎓ with a total gate width of 800 ㎛ in the output stage. These performances could be useful to low-cost and small-sized components for 77 ㎓ automotive radar systems.
Jeon, Dae-Young,Kim, Do-Kywn,Park, So Jeong,Koh, Yumin,Cho, Chu-Young,Kim, Gyu-Tae,Park, Kyung-Ho Elsevier 2018 MICROELECTRONIC ENGINEERING Vol.199 No.-
<P><B>Abstract</B></P> <P>The AlGaN/GaN high electron mobility transistor (HEMT) is considered a promising device for high-power, high-frequency, and high-temperature applications, as well as high-sensitivity sensors. However, several issues related to mobility, interface properties, and series resistance need to be clarified for a better understanding of the physical operation of AlGaN/GaN HEMTs and for further optimization of their performance. In this work, the electrical properties of AlGaN/GaN HEMTs, including the effects of series resistance, and interface properties with mobility degradation factors were investigated in detail. In addition, the low-frequency noise behavior of AlGaN/GaN HEMTs was examined with a carrier number fluctuation model that considered series resistance effects.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Electrical characteristics of AlGaN/GaN HEMTs with several parameters were investigated in detail. </LI> <LI> Series resistance (R<SUB>sd</SUB>) effect significantly causing degradation of effective mobility was de-embedded. </LI> <LI> Gate-to-channel capacitance (C<SUB>gc</SUB>) was obtained with eliminating the parasitic offset capacitance. </LI> <LI> Mobility degradation factors were discussed with interface quality issues. </LI> <LI> Carrier number fluctuation model with considering R<SUB>sd</SUB> effects explained well 1/f noise behavior of AlGaN/GaN HEMTs. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>