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Bandwidth enhancement of K-band CMOS mixer using balun matching for UWB radar
Yu, Han-Yeol,Choi, Sung-Sun,Kim, Sung-Hyun,Kim, Yong-Hoon Wiley Subscription Services, Inc., A Wiley Company 2009 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.51 No.1
<P>A K-band double balanced mixer with 1.9 GHz ultra-wide bandwidth in a 0.18 μm CMOS technology is presented in this article. Baluns with slot pattern ground were applied to the proposed mixer for an ultra-wide band matching in RF and LO ports. The mixer down converts RF signals (23.1–25 GHz) to intermediate frequency signals (100 MHz–1 GHz) using a LO signal of 24.1 GHz. The mixer achieves a conversion gain of 3.4 dB with a RF signal of 24 GHz and a LO signal of 24.1 GHz. A 1 dB compression point of the mixer is −4 dBm, and the mixer consumes 20 mA current with a 1.8 V supply. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 232–235, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23991</P>
Effect of Carrier Diffusion on the Electrical Properties of Si-Zn-Sn-O/Ag/Si-Zn-Sn-O Multilayers
Yu, Jiao Long,Lee, Sang Yeol The Korean Institute of Electrical and Electronic 2018 Transactions on Electrical and Electronic Material Vol.19 No.3
Typically, a parallel circuit model is used to explain the electrical resistivity of oxide-metal-oxide (OMO) multilayers; such a model treats the top, middle, and bottom sublayers independently. However, in the case of semiconductor-metal-semiconductor multilayer systems, this model is not applicable; according to the theory of metal-semiconductor contact, carrier diffusion arising from the difference in the work functions of the materials should also be considered. In this paper, we investigate the effect of carrier diffusion on the electrical properties by changing the thickness of both the top and bottom oxide layers. We find that adjusting the thickness of the oxide sublayers realizes direct control of the carrier density in OMO multilayers.
Yu, Eui-Sang,Lee, Sin-Hyung,Bae, Young-Gyu,Choi, Jaebin,Lee, Donggeun,Kim, Chulki,Lee, Taikjin,Lee, Seung-Yeol,Lee, Sin-Doo,Ryu, Yong-Sang American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.44
<P>A liquid-permeable concept in a metal-insulator-metal (MIM) structure is proposed to achieve highly sensitive color-tuning property through the change of the effective refractive index of the dielectric insulator layer. A semicontinuous top metal film with nanoapertures, adopted as a transreflective layer for MIM resonator, allows to tailor the nanomorphology of a dielectric layer through selective etching of the underneath insulator layer, resulting in nanopillars and hollow voids in the insulator layer. By allowing outer mediums to enter into the hollow voids of the dielectric layer, such liquid-permeable MIM architecture enables to achieve the wavelength shift as large as 323.5 nm/RIU in the visible range, which is the largest wavelength shift reported so far. Our liquid-permeable approaches indeed provide dramatic color tunablility, a real-time sensing scheme, long-term durability, and reproducibility in a simple and scalable manner.</P> [FIG OMISSION]</BR>
A 2.4 /5.2-㎓ Dual Band CMOS VCO using Balanced Frequency Doubler with Gate Bias Matching Network
Sung-Sun Choi,Han-Yeol Yu,Yong-Hoon Kim 대한전자공학회 2009 Journal of semiconductor technology and science Vol.9 No.4
This paper presents the design and measurement of a 2.4/5.2-㎓ dual band VCO with a balanced frequency doubler in 0.18 ㎛ CMOS process. The topology of a 2.4 ㎓ VCO is a cross-coupled VCO with a LC tank and the frequency of the VCO is doubled by a frequency balanced doubler for a 5.2 ㎓ VCO. The gate bias matching network for class B operation in the balanced doubler is adopted to obtain as much power at 2nd harmonic output as possible. The average output powers of the 2.4 ㎓ and 5.2 ㎓ VCOs are -12 ㏈m and -13 ㏈m, respectively, the doubled VCO has fundamental harmonic suppression of -25 ㏈. The measured phase noises at 5 ㎒ frequency offset are -123 ㏈c /㎐ from 2.6 ㎓ and -118 ㏈c /㎐ from 5.1 ㎓. The total size of the dual band VCO is 1.0 ㎜×0.9 ㎜ including pads.
K-band single balanced mixer for ultra-wideband radar in 0.18-μm CMOS technology
Yu, Han-Yeol,Choi, Sung-Sun,Kim, Sung-Hyun,Kim, Yong-Hoon Wiley Subscription Services, Inc., A Wiley Company 2007 MICROWAVE AND OPTICAL TECHNOLOGY LETTERS Vol.49 No.11
<P>A K-band single balanced mixer for ultra-wideband radar using a 0.18-μm CMOS technology is presented. The designed mixer was applied to LC ladder matching technique on RF port and Marchand type balun with slot pattern ground on LO port for wideband operation, respectively. The mixer achieves 3-dB bandwidth of 1.4 GHz, power conversion gain of 1.2 dB, and 1-dB compression point of −3 dBm at RF frequency of 24 GHz and LO frequency of 24.1 GHz. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2697–2700, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22872</P>
Study on a catalytic membrane reactor for hydrogen production from ethanol steam reforming
Yu, Chang-Yeol,Lee, Dong-Wook,Park, Sang-Jun,Lee, Kwan-Young,Lee, Kew-Ho Elsevier 2009 International journal of hydrogen energy Vol.34 No.7
<P><B>Abstract</B></P><P>Ethanol steam reforming in a membrane reactor with catalytic membranes was investigated to achieve important aims in one process, such as improvement in ethanol conversion and hydrogen yield, high hydrogen recovery and CO reduction. In order to confirm the efficiency of reaction and CO reduction, an ethanol reforming-catalytic membrane reactor with water–gas shift reaction (ECRW) in the permeate side was compared with a conventional reactor (CR) and an ethanol reforming-catalytic membrane reactor (ECR). In comparison with the CR, ethanol conversion improvement of 11.9–19% and high hydrogen recovery of 78–87% were observed in the temperature range of 300–600 °C in the ECRW. Compared with CR and ECR, the hydrogen yield of ECRW increased up to 38% and 30%, respectively. Particularly, the ECRW showed higher hydrogen yield at high temperature, because Pt/Degussa P25 loaded in the permeate side showed catalytic activity for the methane steam reforming as well as WGS reaction. Moreover, CO concentration was reduced under 1% by the WGS reaction in the permeate side in the temperature range of 300–500 °C.</P>
Effect of Thermal Annealing on the Optical Properties of In—Si—O/Ag/In—Si—O Multilayer
Yu, Jiao Long,Lee, Sang Yeol American Scientific Publishers 2017 Journal of Nanoscience and Nanotechnology Vol.17 No.5
<P>Low emissive transparent multilayers were fabricated with amorphous Si-doped indium oxide (ISO) transparent semiconductor and metallic Ag by Ag thickness. High transmittance in the visible range of the as-deposit ISO/Ag/ISO multilayer was verified in the experiment results, and the optical properties of an oxide-metal-oxide tri-layer were sensitive to the silver layer's thickness. After annealing, the transmittance in the visible range increased by over 10%, and low emissivity for infrared was maintained.</P>
Hetero-Epitaxial Growth of NiNb03 Thin on GaN/Al2O3 by Pulsed Laser Deposition
Yu-jin Kang,Chae-Ryong Cho,Jae-Yeol Hwang,Jeong-Pil Kim,Sang-A Lee,Se-Young Jeong 한국물리학회 2006 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.49 No.III
LiNbO3 thin film was deposited on GaN/Al2O3 substrate by the pulsed laser deposition technique. These LiNbO3 films were c-axis oriented and showed pure phase without any secondary phase. An X-ray pole figure shows that LiNbO3 film was epitaxially grown on a GaN/Al2O3 substrate with twin boundaries. The surface roughness of the LiNbO3 film deposited at 750 C was 2.369 nm. The refractive index of the LiNbO3/GaN film was determined by using a variable-angle spectroscopic ellipsometer. Films deposited at low substrate temperatures had a refractive index (n 2.12) similar to that of bulk crystal. The relative dielectric constant of all films was smaller than that of a bulk sample, but the crystallinity and refractive index were slightly changed with varying substrate temperatures. We suggest that epitaxial LiNbO3 film on a GaN substrate is useful for designing electro-optical devices such as modulators and deflectors integrated with GaN-based laser diodes and photodetectors.vent