Capacitance Of Transmission Line Research Articles

Modeling of Blumlein Circuit and Calculation of Resistance and Inductance of Laser Plasma

Laser plasma discharge circuit can be simulated by Pspice through practical measuring result. We find that the circuit model of laser plasma should be simulated by a inductance in series with a resistor, furthermore in parallel with a capacitor. The value of the capacitor affect the oscillation frequency of the laser output voltage. The smaller the value of the equivalent capacitor, the less the rise time of the pulse voltage of the laser chamber. Also the rise time of the pulsed voltage of laser can be less when the stray inductance and transmission line capacitance are reduced. It is also found the time –invariant inductance is dependent on the total charge in the discharge area, the time-invariant inductance is dependent on the electric field in the laser chamber.

Study of Photovoltaic Energy Storage by Supercapacitors through Both Experimental and Modelling Approaches

The storage of photovoltaic energy by supercapacitors is studied by using two approaches. An overview on the integration of supercapacitors in solar energy conversion systems is previously provided. First, a realized experimental setup of charge/discharge of supercapacitors fed by a photovoltaic array has been operated with fine data acquisition. The second approach consists in simulating photovoltaic energy storage by supercapacitors with a faithful and accessible model composed of solar irradiance evaluation, equivalent electrical circuit for photovoltaic conversion, and a multibranch circuit for supercapacitor. Both the experimental and calculated results are confronted, and an error of 1% on the stored energy is found with a correction largely within ±10% of the transmission line capacitance according to temperature.

Pulsed RF oscillations on a nonlinear capacitive transmission line

A nonlinear lumped element transmission line (NLETL) that consists of a nonlinear LC ladder network whose capacitors are nonlinear and inductors are linear can be used to produce oscillating pulses. This article describes the implementation of an oscillating pulse generator based on such high voltage nonlinear capacitive lines (NLCL) using commercial-off-the-shelf (COTS) components. Instead of using complex pulse forming networks or pulse forming lines, a storage capacitor and a fast semiconductor switch are used to provide an input pulse onto the cascading LC-elements of the NLCL with good approximation of a rectangular pulse-shape. The design of the NLCL is based on the NLETL circuit model that was developed earlier in-house. Experimental results are compared with simulations predicted by this NLETL model. The voltage modulation and the frequency content of the output pulses are analyzed. The conventional single NLCL produces a signal with a DC offset and a decoupling capacitor is needed at the end of the line to extract the AC component before injecting onto a load such as an antenna. A novel method of directly extracting the AC component without the use of a decoupling capacitor is proposed and investigated. Results of this direct AC extraction, which show the possibility of better performance, are discussed. The frequency tunability of this nonlinear line was also demonstrated.

New Method of Measuring the Positive-sequence Capacitance of T-connection Transmission Lines

A novel method of measuring the positive-sequence capacitance of T-connection transmission lines is proposed. The mathematical model of the new method is explained in detail. In order to obtain enough independent equations, three independent operation modes of T-connection transmission lines during the line measurement are introduced. The digital simulation results and field measurement results are shown. The simulation and measurement results have validated that the new method can meet the needs of measuring the positive-sequence capacitance of T-connection transmission lines. This method has been implemented in the newly developed measurement instrument.

溪洛渡送电广东直流输电工程直流线路故障时的控制保护策略分析

与常规直流输电工程相比，同塔双回线路的电感电容参数发生了较大变化，从而导致故障时的电气量也发生了变化。文章分析了同塔双回直流输电线路故障特点及其常见故障,与常规直流工程进行了对比,介绍了溪洛渡送电广东直流输电工程直流保护策略及其故障时的恢复策略，给出了同塔双回直流工程在保护判据选取和定值设定方面的一些建议。 Great changes have taken place in the inductance and capacitance of double-circuit transmission line on the same tower compared with conventional HVDC project, then electric parameter also changed. This paper analyzed the fault characteristics and usual faults of double-circuit transmission line on the same tower, and compared with conventional DC engineering, this paper also introduces the DC protection strategy and its failure recovery strategy of Xiluo-du-Guangdong HVDC project, some suggestions are given about protection criterion selection and setting value set of double-circuit transmission line on the same tower.

Compact broadband branch-line coupler with centrally loaded open-stub and cascade transmission line

A novel design method for broadband branch-line coupler using parallel capacitance and stepped impedance transmission line is presented in this article. The design uses centrally loaded low- impedance wide open stub as capacitance, and the wavelength of the loaded stub is reduced. Two impedance transformation lines are added on both sides of this loaded stub to achieve a broader band. Simulation and experiment results validate that this method performs well in size reduction and band broadening. V C 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2101-2103, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27037

VLSI interconnects and their testing: prospects and challenges ahead

PurposeThe purpose of this paper is to explore the functioning of very‐large‐scale integration (VLSI) interconnects and modeling of interconnects and evaluate different approaches of testing interconnects.Design/methodology/approachIn the past, on‐chip interconnect wires were not considered in circuit analysis except in high precision analysis. Wiring‐up of on‐chip devices takes place through various conductors produced during fabrication process. The shrinking size of metal‐oxide semiconductor field effect transistor devices is largely responsible for growth of VLSI circuits. With deep sub‐micron (DSM) technology, the interconnect geometry is scaled down for high wiring density. The complex geometry of interconnects and high operational frequency introduce wire parasitics and inter‐wire parasitics. These parasitics causes delay, power dissipation, and crosstalk that may affect the signal integrity in VLSI system. Accurate analysis, sophisticated design, and effective test methods are the requirement to ensure the proper functionality and reliability of VLSI circuits. The testing of interconnect is becoming important and a challenge in the current technology.FindingsThe effects of interconnect on signal integrity, power dissipation, and delay emerges significantly in DSM technology. For proper performance of the circuit, testing of interconnect is important and emerging challenge in the nanotechnology era. Although some work has been done for testing of interconnect, however, it is still an open area to test the parasitics effects of VLSI/ultra‐large‐scale integration interconnects. Efforts are required to analyze and to develop test methods for crosstalk, delay and power dissipation in current technology with solutions to minimize this effect.Originality/valueThis paper reviews the functioning of VLSI interconnects from micrometer to nanometer technology. The development of various interconnect models from simple short circuit to latest resistance inductance capacitance transmission line model are discussed. Furthermore, various methodologies such as built‐in self test and other techniques for testing interconnect for crosstalk and delay are discussed.

A Common Electromagnetic Framework for Carbon Nanotubes and Solid Nanowires—Spatially Dispersive Conductivity, Generalized Ohm's Law, Distributed Impedance, and Transmission Line Model

General equations are presented for the spatially dispersive conductivity, distributed impedance, Ohm's law relation, and transmission line model of both carbon nanotubes (CNTs) and solid material nanowires. It is shown that spatial dispersion results in an intrinsic (material-dependent) transmission-line capacitance. Spatial dispersion is numerically unimportant in metal nanowires, but leads to a shift in propagation constant of a few percent for CNTs and semiconducting nanowires. Theoretically, spatial dispersion is important for both nanowires and nanotubes, and is necessary to preserve the inductance-capacitance-velocity relation , where is kinetic inductance, is intrinsic capacitance, and is electron Fermi velocity. It is shown that in order to obtain the correct intrinsic capacitance, it is necessary to use a charge-conserving form of the relaxation-time approximation to Boltzmann's equation. Numerical results for the propagation constant of various nanowires and CNTs are presented. The general formulation developed here allows one to compute, and directly compare and contrast, properties of CNTs and solid nanowires.

Energetical Modeling of Lithium-Ion Batteries Including Electrode Porosity Effects

All electrochemical batteries are characterized by an electrical behavior that depends on temperature, state of charge, and current. In the case of lithium-ion accumulators, the energetical behavior is moreover deeply marked by line effects, due to the porosity of both electrodes. This paper deals with investigations on an accurate energetical modeling of lithium-ion battery. It is shown in particular that electrode porosity can be taken into account by means of a diffusion impedance represented by a capacitive transmission line. An energetical model, which couples this line with a current independent capacitance, is proposed and characterized at constant temperature (20°C) over different state-of-charge intervals (5%) and for different currents. Reactant diffusion within the electrolyte and relaxation period after discharge are investigated as well. Validation tests carried out on a 6.8-Ah lithium-ion element are conclusive.

Short wavelength comb-type capacitive transmission line for application to miniaturised on-chip passive components on MMIC

A short wavelength CCTL (comb-type capacitive transmission line) structure on MMIC has been developed for application to miniaturised on-chip passive components. Of all transmission line structures that have been reported to date, the CCTL structure shows the shortest guided wavelength. Using the CCTL structure, a highly miniaturised impedance transformer has been fabricated on GaAs MMIC. The impedance transformer shows good RF performances in a broad band from S- to X-band, and its size is 0.042 mm2, which is 0.95% of the size of the conventional transformer on MMIC.

Direct computation of multiconductor transmission line capacitance and charge distribution

The per-unit-length capacitance parameter of multiconductor transmission line (MTL) is commonly extracted with indirect matrix transform method, which is complex and time-consuming. To solve the problem, an improved method to directly compute the MTL capacitance is proposed, which can be applied in the transmission line structure with arbitrary shaped cross-section and arbitrary separate distance. This method imports voltage conversions and matrix operations to simplify the complexity, improves computational efficiency by about 600% with results as accurate as previous method. The novel method presents a clear charge distribution map of MTL, whereas precious method will experience a tortuous process to get charge distribution.

A generalized method to improve the location accuracy of the single-ended sampled data and lumped parameter model based fault locators

The necessity for very high accuracy in fault location is generally becoming more and more important. In this paper, a new generalized algorithm which can improve the accuracy of all fault location algorithms based on the lumped parameter model and single-ended data is presented. The measured distance resulting from the lumped parameter model can be converted to the positive sequence measured impedance matching with the model. Then, the relation between real distance and positive sequence measured impedance of fault circuit based on Bergeron model can be derived according to the analysis of solid grounded faults. Then the improved algorithm resulting from the relation of real distance and measured distance can be obtained. Theoretically, the proposed algorithm is independent of shunt distributed capacitance of transmission lines. Besides, the algorithm is based on power–frequency voltages and currents, and hence high sampling rate is unnecessary. Therefore, it can be implemented in the existing protection devices easily. This paper presents the theory of the technique and the results of ATP simulation tests to demonstrate its performance.

Analytical timing model for inductance-dominant interconnect based on traveling wave propagation

As accurate and efficient timing prediction is very important for integrated circuit design, an analytical timing model for inductive-effect dominated resistance–inductance–capacitance (RLC) transmission line with resistive driver and capacitive load is proposed by virtue of traveling wave propagation and perturbation technique. This model is theoretically stable and computationally efficient. Comparison with other analytical and SPICE models illustrates that this timing model can achieve excellent accuracy for inductance-dominant interconnect. Incorporating with decoupling technique, this model could be readily extended to coupled interconnects.

High-Efficiency Class-FE Tuned Power Amplifiers

The results of exact time domain analysis of the novel switched-mode tuned Class-FE power amplifiers with a parallel quarterwave transmission line are presented with analytical derivation of the optimum load network parameters. Effects of the quarterwave transmission line and collector capacitance on the current and voltage waveforms are discussed. A Class-FE power amplifier is based on the combination of a class-F operating mode with Class-E switching conditions, thus extending the Class-F operation to higher frequencies for driving signals with duty cycles D < 0.5. The ideal collector voltage and current waveforms demonstrate a possibility of 100% efficiency without overlapping between each other. A possibility of alternative load network implementation including a series quarterwave transmission line or lumped-element approximation is also considered. The switched-mode Class-FE power amplifiers with a quarterwave transmission line offer a new challenge for RF and microwave power amplification providing high-efficiency operation conditions.

New Method of Live Line Measuring the Inductance Parameters of Transmission Lines Based on GPS Technology

Based on global positioning system (GPS) technology and differential equation algorithms, a new approach to live line measuring of the inductance parameters of transmission lines with mutual inductance is proposed. The principles and mathematical model of the new method are explained in detail. Data processing by least square algorithm is introduced. To take into account the influence of distributed capacitance of transmission lines, a modified mathematical model is introduced. The hardware structure of the measuring system is given and real-time digital simulator (RTDS) experimental results validate the accuracy of the test system. Finally, an example of live line measuring two 220-kV transmission lines with mutual inductances is given. A comparison of measurement results between the differential equation method and the conventional method is also shown.

Computation of the Capacitance of the Inhomogeneous Insulated Transmission Line

A boundary element method (BEM) procedure to obtain the capacitance of inhomogeneous insulated transmission lines is presented. The geometry consists of multiple, parallel and insulated conductor cylinders. The BEM matrix equation associated with piecewise homogeneous insulated transmission line is derived. Two representative computational examples, eccentric coaxial cable partially filled with dielectric and transmission line consisting of two parallel dielectric-coated cylinders, are given to validate the accuracy and efficiency of the BEM.

Distributed MEMS analog phase shifter with enhanced tuning

The design, fabrication, and measurement of a tunable microwave phase shifter is described. The phase shifter combines two techniques: a distributed capacitance transmission line phase shifter, and a large tuning range radio frequency (RF) microelectromechanical system (MEMS) capacitor. The resulting device is a large bandwidth, continuously tunable, low-loss phase shifter, with state-of-the-art performance. Measurements indicate analog tuning of 170deg phase shift per dB loss is possible at 40 GHz, with a 538deg phase shift per centimeter. The structure is realized with high-Q MEMS varactors, capable of tuning C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</sub> /C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">min</sub> = 3.4. To our knowledge, this presents the lowest loss analog millimeter wave phase shifter performance to date

Double-image Green's function method for 3-D capacitance and conductance extraction of on-chip transmission lines

A new double-image Green's function approach is developed to compute the frequency-dependent capacitance and conductance for three-dimensional multilayered on-chip transmission lines on silicon substrate. The ε-algorithm of the Pade approximation is adopted to reduce the time for establishing the coefficient matrix. The parameters gained from this new approach are shown to be in good agreement with the data obtained by the total charge Green's function method.

THE VARIATIONAL CLOSED-FORM FORMULAE FOR THE CAPACITANCE OF ONE TYPE OF CONFORMAL COAXIAL LINES

The variational closed-forms of the capacitance formulae of a type of conformal coaxial lines are presented in this paper with the assumption that the equipotential lines are conformal to the contour of the coaxial line. The variational extreme formula of the functional of continuous functions is first obtained. Then the variational stable and analytical expression of the capacitance is deduced. Considering the actual applications, we give the variational stable formulae of the capacitances of the conformal coaxial transmission lines whose contours are homogeneous curves of the 1st, 2nd and n-th order. Examples are given including the conformal regular polygonal, elliptical and high- order elliptical coaxial lines.

Capacitive transmission lines in coplanar waveguide for millimeter-wave integrated circuit design

For use in millimeter-wave integrated circuits, theoretical and experimental design data for various useful capacitive transmission lines in coplanar waveguide on gallium arsenide are presented. Multifinger and metal-insulator-metal (MIM) lines enabling low characteristic impedance of the order of 10 /spl Omega/ as well as broadband capacitive coupled transmission lines are investigated. Simple design rules and accurate models validated with measurements up to 120 GHz demonstrate that such planar transmission lines can be used in monolithic microwave integrated circuits (MMICs) to extend the impedance range and the design flexibility with respect to the conventional CPW.