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IEEE PES Asia-Pacific Power and Energy Engineering Conference (APPEEC)

作者： Shuheng Dan Electr. Power & Autom. Eng. Dept. Shanghai Univ. of Electr. Power Shanghai China

In this paper the problems emerging during the process of developing the huge power grid are presented and discussed respectively. The first is the short circuit current which improves with the installation capacity. So in order to limit the short circuit current some concerning methods are taken while on the contrary some methods sacrifice the reliability of the whole power system. Second the power flow in the power grid is not easy to judge immediately so it will make the dispatch under the fault situation becomes difficult and more of the fault may be induced by the not proper dispatching. Third problem is the criterion of the N-l. Under fault situation this criterion can be changed to N-K. The fourth problem is of the second side equipment. The telecommunication board itself can make four or even more of the transmission lines to trip though the system on the high voltage side can fulfill the N-l criterion.

关键词： Power grids Substations Circuit breakers Short circuit currents Power system reliability Power transmission lines Circuit faults distributed parameter circuits Voltage Power generation

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A 50-GS/s 5-b ADC in 0.18-µm SiGe BiCMOS

A 50-GS/s 5-b ADC in 0.18-µm SiGe BiCMOS

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Microwave, MTT-S International Symposium

作者： Jaesik Lee Young-Kai Chen Alcatel-Lucent Technologies Inc. Murray Hill NJ USA

A 5-b 50-GS/s time-interleaved ADC is presented in 0.18-μm SiGe BiCMOS. The two-channel interleaved flash architecture is used to increase the conversion rate. The front-end three-stage distributed track-and-hold amplifier is devised to improve the dynamic performance. The ADC features SNDR as high as 23.1 dB with 20 GHz sine wave input at 50 GS/s conversion rate, and the third harmonic distortion is -36.5 dBc. It shows the measured resolution bandwidth of 18 GHz and the FOM of 9 pJ per conversion step with power consumption of 5.4 W.

关键词： Silicon germanium Germanium silicon alloys BiCMOS integrated circuits Clocks Bandwidth Switches distributed amplifiers Millimeter wave technology Optical receivers distributed parameter circuits

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Nonuniform Transmission Line Simulation with Circuit Simulator

Nonuniform Transmission Line Simulation with Circuit Simulat...

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IEEE Mediterranean Electrotechnical Conference

作者： Jacek Izydorczyk Silesian University of Technology

ISBN: (纸本)9781424457939

In the present article a method of lossless nonuniform transmission line (NUTL) analysis is proposed. The method reduces analysis of the NUTL to the analysis of cascaded sections of linear varied transmission line (LNTL). Frequency response of each section is described by Bessel functions. Therefore direct implementation of the method in circuit simulator is usually impossible. LNTL input-output relations can be approximated by rational function in frequency domain. It is a form of Pade approximation. The model can be implemented in circuit simulator as an active circuit. Unfortunately circuit input reflection coefficient is distorted in unacceptable manner. Input reflection coefficient is equal for DC to one irrespectively of order of Pade approximation. Author proposed a method which deforms rational approximation residua slightly so frequency response of the model is disturbed minimally and passivity of the circuit is preserved. Synthesis of the passive modeling circuit was conducted for broad range of LNTL slope parameter. The circuit was a cascade connection of Darlington C-type sections. parameters of the sections were approximated by polynomial regression functions. The specific insensitivity of cascaded circuits on parameter changes assures high accuracy of the model despite inevitable errors in process of parameter regression.

关键词： Frequency-domain analysis circuit simulator distributed parameter circuits Cascade connections Pade approximation Passivity rational functions frequency response Reflection coefficient

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Modeling of Switching Transient on Long Nonuniform Transmission Line Using Precise Integration Method in Time Domain

Modeling of Switching Transient on Long Nonuniform Transmiss...

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Biennial Institute of Electrical and Electronics Engineers Conference on Electomagnetic Field Computation

作者： Zhen Li Shunchao Wang Jinliang He Department of Electrical Engineering and Applied Electronic Technology Tsinghua University

this paper uses precise integration method in time domain (PITD) to simulate the electromagnetic transient behavior of the long nonuniform transmission line. The matrix exponential integrator is computed using Krylov ... 详细信息

ISBN: (纸本)9781424470594

关键词： distributed parameter circuits Integration Methods TIME-DOMAIN switching transients scaling method Modeling DNA Integration integration Transients Transient

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Analytical Solution for Voltage-Step Response of Lossy distributed RC Lines

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IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES 2009年第2期57卷 449-457页

作者： Punning, Andres Jalviste, Erko Univ Tartu Inst Technol Intelligent Mat & Syst Lab EE-50411 Tartu Estonia Univ Tartu Inst Phys EE-51014 Tartu Estonia

This paper presents an analytical solution for the voltage-step response of finite-length open-ended distributed lossy RC lines. Three line configurations with differently arranged distributed transversal conductivities causing charge loss are considered. Telegrapher's equation for voltage is solved at three different intial/boundary conditions using the method of Fourier series.

关键词： distributed parameter circuits lossy circuits RC circuits transient response

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Introducing Nonuniform Grids into the FDTD Solution of the Transmission-Line Equations by Renormalizing the Per-Unit-Length parameters

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IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY 2009年第3期51卷 818-824页

作者： Armenta, Roberto B. Sarris, Costas D. Univ Toronto Edward S Rogers Sr Dept Elect & Comp Engn Toronto ON M5S 3G4 Canada

A challenging aspect of using the finite-difference time-domain (FDTD) method to solve nonuniform transmission-line equations is to choose a discretization grid with an adequate spatial resolution. When the per-unit-length parameters have strong variations, an efficient problem-solving strategy requires the use of a nonuniform discretization grid. This paper presents a nonuniform gridding method that makes use of an analytically defined coordinate transformation to map a nonuniformly spaced grid onto a uniformly spaced grid where the standard FDTD time stepping equations can be applied. This approach absorbs all the details of the nonuniform grid into effective or renormalized per-unit-length parameters.

关键词： distributed parameter circuits finite-difference time-domain (FDTD) methods transmission lines

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Multimode-Resonator-Based Bandpass Filters

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IEEE MICROWAVE MAGAZINE 2009年第2期10卷 88-98页

作者： Sun, Sheng Zhu, Lei Nanyang Technol Univ Sch Elect & Elect Engn Singapore 639798 Singapore

This article describes a class of recently developed multiple-mode-resonator-based bandpass filters for ultra-wide-band (UWB) transmission systems. These filters have many attractive features, including a simple design, compact size, low loss and good linearity in the UWB, enhanced out-of-band rejection, and easy integration with other circuits/antennas. In this article, we present a variety of multiple-mode resonators with stepped-impedance or stub-loaded nonuniform configurations and analyze their properties based on the transmission line theory. Along with the frequency dispersion of parallel-coupled transmission lines, we design and implement various filter structures on planar, uniplanar, and hybrid transmission line geometries.

关键词： Band pass filters Transmission line theory Resonator filters Planar transmission lines distributed parameter circuits Ultra wideband technology Linearity Ultra wideband antennas Frequency Geometry

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The Transmission Line as a Simple Example for Introducing Integral Equations to Undergraduates

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IEEE TRANSACTIONS ON EDUCATION 2009年第4期52卷 459-469页

作者： Rothwell, Edward J. Michigan State Univ Dept Elect & Comp Engn E Lansing MI 48824 USA

Integral equations are becoming a common means for describing problems in electromagnetics, and so it is important to expose students to methods for their solution. Typically this is done using examples in antennas, scattering, or electrostatics. Unfortunately, many difficult issues arise in the formulation and solution of the associated equations. It is instead proposed to use examples from transmission lines, a topic with which undergraduate students are both familiar and comfortable. In this paper, the formulations of integral equations for both uniform and nonuniform lines are undertaken, simple moment-method solutions are implemented, and the accuracies of the solutions are explored.

关键词： distributed parameter circuits electromagnetic engineering education integral equations moment methods transmission lines

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Application of Nonuniform Transmission Lines to Ultra Wideband Pulse Shaping

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IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS 2009年第12期19卷 795-797页

作者： Rulikowski, Pawel Barrett, John Cork Inst Technol Ctr Adapt Wireless Syst Dept Elect Engn Cork Ireland

The work presented in this letter demonstrates that nonuniform transmission lines (NUTLs) can be used for pulse shaping applications in ultra wideband pulsed systems and presents an approach to their design for this application. The pulsed waveforms generated are modified Hermite polynomials and encoded pulse trains thereof and are characterised by a broad bandwidth ranging from near DC to over 10 GHz and relatively long temporal duration in the region of nanoseconds. These pulses are more mathematically complex and at least three times higher bandwidth than previously has been reported in the literature. It is also believed to be the first time that modified Hermite polynomial pulses have been generated in practice. The NUTL design approach is verified by test structures fabricated on FR4 circuit board. The results demonstrate that NUTLs, which are completely passive structures, allow generation of complex pulse shapes in applications requiring fast, transient waveforms.

关键词： distributed parameter circuits nonuniform transmission line pulse generation transient response ultra wideband (UWB)

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Comments on "a symmetrical four-port microstrip coupler for crossover application"

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IEEE Transactions on Microwave Theory and Techniques 2009年第7期57卷 1859-1860页

作者： Chiou, Yi-Chyun Tsai, Cheng-Hsiu Kuo, Jen-Tsai Department of Communication Engineering National Chiao Tung University Hsinchu 300 Taiwan

In the paper of Chen and Yeo (2007), the authors demonstrate a four-port coupler for crossover application. In their eigenmode model analysis, the entire circuit is decomposed into tapers and two rings with four external arms. In formulation, the eigenadmittance of the inner substructure is taken account as the load of that of the outer one. A cascade of P short sections is then used to approximate the taper and incorporated into the model of the composite structure by successively applying the input admittance formula of a loaded transmission line. Finally, one prototype circuit solution obtained by an optimization process is demonstrated. In this paper, the transmission line theory is applied to the circuit analysis. It is found that the circuit structure is so versatile for the crossover application that infinite numbers of solutions can be simply obtained by solving two simultaneous equations. In addition, the tapers for input/output matching can be saved, leading not only to circuit area reduction, but also to formulation simplification. A microstrip coupler is fabricated and measured for confirmation.

关键词： Microstrip Coupling circuits Circuit analysis Transmission line theory Arm Admittance distributed parameter circuits Prototypes Equations Impedance matching

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