• Title/Summary/Keyword: $S_{11}$-parameter

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An Analysis of Bias-Dependent S11-Parameter in Multi-Finger MOSFETs (Multi-Finger MOSFET의 바이어스 종속 S11-파라미터 분석)

  • Ahn, Jahyun;Lee, Seonghearn
    • Journal of the Institute of Electronics and Information Engineers
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    • v.53 no.12
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    • pp.15-19
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    • 2016
  • The gate bias dependence of kink phenomenon with a large deviation from the resistance circle in Smith chart is observed in the frequency response of $S_{11}$-parameter for large multi-finger RF MOSFETs. For the first time, this bias dependence is analyzed by measuring magnitude and phase of $S_{11}$-parameter, input resistance and input capacitance. As a result, $V_{gs}$ dependent $S_{11}$-parameter is largely changed by the magnitude of input capacitance as well as dominant pole and zero frequencies of input resistance. At $V_{gs}=0V$, the kink phenomenon occurs in the high frequency region because of very small phase difference of $S_{11}$-parameter and high pole frequency of input resistance. However, the kink phenomenon at higher $V_{gs}$ is generated in the low frequency region owing to large phase difference and low pole frequency.

Measurement and Analysis of Gate Finger Number Dependence of Input Resistance for Sub-micron MOSFETs (Sub-micron MOSFET을 위한 입력 저항의 게이트 핑거 수 종속성 측정 및 분석)

  • Ahn, Jahyun;Lee, Seonghearn
    • Journal of the Institute of Electronics and Information Engineers
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    • v.51 no.12
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    • pp.59-65
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    • 2014
  • Two input resistances converted from $S_{11}$-parameter and $Z_{11}$-parameter of MOSFETs with various gate finger numbers Nf were measured in low frequency region. The 1/Nf dependent input resistance from $S_{11}$-parameter exhibits much lower values than that from $Z_{11}$-parameter in the range of $Nf{\leq}64$. This 1/Nf dependence was theoretically verified by using Nf dependent nonlinear equation derived from a MOSFET equivalent circuit.

Color lens CIE L*a*b* coordination transfer by tinted time (착색시간에 따른 칼라렌즈 색좌표 이동)

  • Jeong, Byung-Mann;Park, Kwang-Ho;Kim, Yong-Geun
    • Journal of Korean Ophthalmic Optics Society
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    • v.8 no.1
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    • pp.53-57
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    • 2003
  • R, G, Y, B color lenses Manufactured increasing tinted time by 5 min term. CIE $L^*a^*b^*$ coordination's analysis used spectrophotometer and CIE $L^*a^*b^*$ color system. CIE $L^*a^*b^*$ coordination transfer form about tinted time being $$b^*(Y-B)={\beta}a^*+{\alpha}$$ change to do linear almost. In red case, move in $G{\rightarrow}R$, $B{\rightarrow}Y$ form tinted time increases, and Parameter ${\alpha}$, ${\beta}$ value got each -3.49 and 0.90. In green case, CIE $L^*a^*b^*$ coordination transfer form is $R{\rightarrow}G$, $B{\rightarrow}Y$ form. Got the pure green color color in 10 min's tinted time. Parameter ${\alpha}$, ${\beta}$ value got each -0.72 and -0.55. Get into pure yellow and blue color case tinted time increases. Parameter ${\alpha}$, ${\beta}$ value are 14.11 and 1.58 in yellow, and Parameter ${\alpha}$, ${\beta}$ value are -11.62 and 1.30 in blue color.

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A MAC Parameter Optimization Scheme for IEEE 802.11e-based Multimedia Networks (IEEE 802.11e 기반 멀티미디어 네트워크를 위한 MAC 매개 변수 최적화 방법)

  • Sung, Min-Young
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.2
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    • pp.455-461
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    • 2008
  • Enhanced Distributed Channel Access (EDCA) is a channel access scheme adopted by the IEEE 802.11e draft standard for QoS-enabled wireless local area networks. It classifies traffic into separate Access Categories (ACs) and achieves service differentiation by allowing each AC to have its own values of channel access parameters. This paper proposes a scheme to dynamically adapt the EDCA parameters to traffic environment so that they both maximize the throughput of non real-time traffics and meet the delay and throughput constraints of real-time traffics. For this purpose, we develop a design algorithm for efficient exploration of the EDCA parameter space. Using the algorithm, we derive a Pareto curve fur delay-throughput trade-off in each anticipated traffic environment. The Pareto database can then be used to optimally adjust the parameter according to the traffic environment and administrative policies. Simulation results show that compared with the default parameter configuration, the proposed scheme is better for delay, throughput guarantee and can improve the throughput of non real-time traffics by 12% on average.

AN ADAPTIVE SEQUENTIAL PROBABILITY RATIO TEST IN THE AUTOREGRESSIVE PROCESS

  • Choi, Ki-Heon
    • Journal of applied mathematics & informatics
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    • v.11 no.1_2
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    • pp.373-378
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    • 2003
  • consider the problem of sequentially hypotheses about a parameter $\theta$ in the presence of the nuisance parameter $\rho$. and we investigate further to computing the error probabilities and expected sample sizes in the frequentist properties of the adaptive S.P.R.T. for $\theta$.

Mixed $H^2/H^{\infty}$ Filter Design for Linear Parameter Varying System (선형 파라마터 변이 시스템에 대한 혼합 $H^2/H^{\infty}$ 필터 설계)

  • 이갑래;윤한오
    • Journal of the Korean Institute of Telematics and Electronics S
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    • v.34S no.11
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    • pp.73-79
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    • 1997
  • This paepr is concerned with the design of linear parameter varying filter that ensures H$^{2}$/$H^{\infty}$ performance for a class of linear parameter varying(LPV) plants. The state space matrices of plant are assumed to be dependent affinely on a vector of time varying parameter, and each parameter is assumed to be measured in real time. Using the linear matrix inequalities(LMIs), we can solve the synthesis problem and the solution of LMIs is carried out off-line. The designed filter is parameter varying and automatically scheduled along parameter trajectories. Because the solution of LMIs is carried out off-line, computation time of filter gain is reduced. The validity of the proposed algorithm is verifed through computer simulation..

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A new lumped equivalent circuits for spiral inductor with metal thickness (금속의 두께를 고려한 나선형 인덕터의 집중형 등가 회로의 제안)

  • 오데레사;김흥수
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.34D no.9
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    • pp.21-27
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    • 1997
  • Square spiral inductors are designed with EM program in accordance with the inner diameter and the metal thickness which is 0.2.mu.m and 20.mu.m respectively. We propose a parameter extraction method based on the S-parameter. Lumped equivalent circuits of spiral inductors are analyed with reflection coefficient S$_{11}$, of witch freqency rnage is 1~10GHz. When metal thickness is 0.2.mu.m, S$_{11}$ with EM simulation is not the same as S$_{11}$ that of SPICE simulation. So we suggests a new lumped equivalent circuits which compensate circuits. Te new lumped equivalent circuits are adequate for other inductor with small scale at high frequencies.ncies.

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Identifiability of Ludwik's law parameters depending on the sample geometry via inverse identification procedure

  • Zaplatic, Andrija;Tomicevic, Zvonimir;Cakmak, Damjan;Hild, Francois
    • Coupled systems mechanics
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    • v.11 no.2
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    • pp.133-149
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    • 2022
  • The accurate prediction of elastoplasticity under prescribed workloads is essential in the optimization of engineering structures. Mechanical experiments are carried out with the goal of obtaining reliable sets of material parameters for a chosen constitutive law via inverse identification. In this work, two sample geometries made of high strength steel plates were evaluated to determine the optimal configuration for the identification of Ludwik's nonlinear isotropic hardening law. Finite element model updating(FEMU) was used to calibrate the material parameters. FEMU computes the parameter changes based on the Hessian matrix, and the sensitivity fields that report changes of computed fields with respect to material parameter changes. A sensitivity analysis was performed to determine the influence of the sample geometry on parameter identifiability. It was concluded that the sample with thinned gauge region with a large curvature radius provided more reliable material parameters.

Post-buckling analysis using a load-displacement control (하중과 변위의 동시제어에 의한 좌굴후 현상해석)

  • Kwon, Y.D.;Lim, B.S.;Park, C.;Choi, J.M.
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.11
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    • pp.1931-1942
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    • 1997
  • A new load/displacement parameter method is developed for the cases that loads are applied to one or more points, and displacements of a structure are controlled at one or more points sinultaneously. The procedure exploits a generalized Riks method, which utilizes load/displacement parameters as scaling factors in order to analyze the post-buckling phenomena including snap-through or snap-back. A convergence characteristic is improved by employing new relaxation factors in incremental displacement parameter, particularly at the region where exhibits severe numerical instability. The improved performance is illustrated by means of numerical example.

Analysis of Excluded Volume Effect in Theta Solvent Systems of Polymethyl Methacrylate and Polystyrene by Means of a Modified Scaled Temperature Parameter

  • Kim, Myeong Ju;Park, Il Hyeon
    • Bulletin of the Korean Chemical Society
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    • v.22 no.11
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    • pp.1255-1260
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    • 2001
  • The expansion of two different kinds of hydrodynamic size of polymethyl methacrylate (PMMA Mw: 1.56- 2.04 ${\times}$ 106 g/mol) has been measured by dynamic light scattering and viscometry above the Flory $\theta$ temperature of the variou s solvents such as n-butyl chloride, 3-heptanone, and 4-heptanone. The expansion of PMMA chains was analyzed in terms of universal temperature parameters and also compared with previous results of polystyrene (PS) system. First it was found that simple $\tau/{\tau}c$ parameter no longer had its universality for the expansion behavior of hydrodynamic size in the chemically different linear polymer chains. However after modifying ${\tau}/{\tau}c$ parameter into $(Mw/Ro2)3}2(\tau/\tauc)$, we observed a much better universality for both PMMA and PS systems. Here Mw, Ro, $\tau[=(T-{\theta}$)/${\theta}$]$, and ${\tau}c[=({\theta}-Tc)/Tc]$ are defined as the weight average molecular weight, the unperturbed end-to-end distance, the reduced temperature and the reduced critical temperature, respectively.