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Characterization of a CMOS 135-GHz Low Noise Amplifier with Two Different Noise Measurement Methods
Doyoon Kim,Sooyeon Kim,Kiryong Song,Jungsoo Kim,Junghwan Yoo,Jae-Sung Rieh 대한전자공학회 2018 Journal of semiconductor technology and science Vol.18 No.4
A D-band low-noise amplifier (LNA) has been developed based on a 65-nm CMOS technology, which showed a measured peak gain of 16.1 dB at 134.5 GHz. The noise property of the fabricated amplifier was characterized with two different noise measurement techniques: the cryogenic Y-factor method and the N-times power method. The two methods showed a minimum value of the noise figure of 10.7 dB and 14.7 dB, respectively.
Kim, Doyoon,Dong, Hongjie,Zhang, Hong AIMS PRESS 2016 Discrete and continuous dynamical systems Vol.36 No.9
<P>We prove the unique solvability in weighted Sobolev spaces of non divergence form elliptic and parabolic equations on a half space with the homogeneous Neumann boundary condition. All the leading coefficients are assumed to be only measurable in the time variable and have small mean oscillations in the spatial variables. Our results can be applied to Neumann boundary value problems for stochastic partial differential equations with BMOx coefficients.</P>
A $D$ -Band CMOS Amplifier With a New Dual-Frequency Interstage Matching Technique
Kim, Dong-Hyun,Kim, Doyoon,Rieh, Jae-Sung Professional Technical Group on Microwace Theory a 2017 IEEE Transactions on Microwave Theory and Techniqu Vol. No.
<P>A new interstage matching technique has been proposed and successfully applied to a D-band amplifier in a 65-nm CMOS technology. The proposed technique is based on a simultaneous conjugate matching at the interstages of multistage amplifiers at two frequencies, resulting in an increased bandwidth. The six-stage amplifier designed based on this technique shows a peak gain of 13.8 dB at 113.7 GHz with a 3-dB bandwidth of 11.2 GHz (110.6-121.8 GHz) without balun loss compensation, while consuming a dc power of 40 mW. Measured noise figure shows a minimum value of 10.8 dB at 115 GHz. The output P-1 dB and the saturation output power P-sat are -14 and -3 dBm, respectively. The circuit occupies an area of 1100 x 550 mu m(2).</P>
Integer Ambiguity Search Technique Using Separated Gaussian Variables
Doyoon Kim,Jaegyu Jang,Changdon Kee 한국항공우주학회 2004 International Journal of Aeronautical and Space Sc Vol.5 No.2
Real-Time Kinematic GPS positioning is widely used for many applications. Resolving ambiguities is the key to precise positioning. Integer ambiguity resolution is the process of resolving the unknown cycle ambiguities of double difference carrier phase data as integers. Two important issues of resolving are efficiency and reliability. In the conventional search techniques, we generally used chi -square random variables for decision variables. Mathematically, a chi-square random variable is the sum of mutually independent, squared zero-mean unit-variance normal (Gaussian) random variables. With this base knowledge, we can separate decision variables to several normal random variables. We showed it with related equations and conceptual diagrams. With this separation, we can improve the computational efficiency of the process without losing the needed performance. If. we average separated normal random variables sequentially, averaged values are also normal random variables. So we can use them as decision variables, which prevent from a sudden increase of some decision variable. With the method using averaged decision values, we can get the solution more quickly and more reliably. To verify the performance of our proposed algorithm, we conducted simulations. We used some visual diagrams that are useful for intuitional approach. We analyzed the performance of the proposed algorithm and compared it to the conventional methods.
Adsorption of cadmium(II) from aqueous solutions by thiol-functionalized activated carbon
Kim, Doyoon,Jung, Young Wook,Kwon, Seokjoon,Park, Jae-Woo IWA Publishing 2011 Water science & technology--water supply Vol.11 No.1
<P>Thiol groups of adsorbent surfaces offer strong affinities for heavy metal ions, such as Hg(II), Pb(II), Cd(II), and so on. In this study, thiol group was impregnated to activated carbon by a series of treatments of oxidation and chlorination followed by 1,2-ethanedithiol introduction in order to investigate the adsorption properties of Cd(II) in aqueous solution. Batch sorption experiments were carried out to study kinetics, and the effect of Mg(II) and different pH conditions on Cd(II) sorption. Sequential extraction experiments were performed to understand binding characteristics. In general, thiol-functionalization improved the removal of Cd(II) by activated carbon in aqueous solution. Compared to untreated activated carbon, over a factor of four of the maximum sorption capacity enhancement was achieved. The presence of Mg(II) interfered Cd(II) sorption, but the degree of the sorption interference was alleviated significantly. Cd(II) sorption occurred more rapidly due to more involvement of ion exhchange by thiol- functionalization.</P>