Capacitive Transmission Research Articles

A 57-GHz CMOS Reflection Amplifier in 90-nm CMOS

A reflection amplifier is designed using 90-nm bulk CMOS technology for applications in the 60-GHz frequency band. Different from the conventional configurations, a proposed capacitive transmission line at the transistor source port results in negative input resistance and return gain. The return gain is further enhanced by adding an inductor at the drain port. The fabricated die occupies 0.38 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and consumes low dc power of 4.4 mW. The measured data show a peak gain of 8.4 dB at 57 GHz.

Analysis and Design of a Multi-Resonant Circuit for Applications of Wireless Capacitive Power Transmission

Capacitive technology for wireless power transmission has been shown to be a good option for charging the batteries of electric vehicles. It offers better coupling between the transmitter and the receiver than inductive power transmission. On the other hand, it has some disadvantages; for example, it is very sensitive to the distance between plates. Several ideas have recently been proposed to overcome this disadvantage. However, a proper analysis methodology is still lacking, as is a proper design procedure for the circuits used in capacitive transmission. In this paper, an analysis and design methodology is presented for applying the Z-tank resonant circuit to capacitive power transmission, and the theoretical design methodology is based on normalized equations with respect to the operating resonance frequency. The analysis methodology and design procedure result in a circuit where the resonance frequency remains constant despite changes in the distance between the capacitive plates. The simulation results validate the proposal; to ensure robust, realistic simulation results, parasitic elements were considered in all reactive components, and robust models were built for the switching elements, such as MOSFETs and diodes. The results show that the multi-resonant characteristic of the circuit achieves maximum energy transfer and high efficiency.

Energy current and computing.

In his seminal Electrical papers, Oliver Heaviside stated ‘We reverse this …' referring to the relationship between energy current and state changes in electrical networks. We explore implications of Heaviside's view upon the state changes in electronic circuits, effectively constituting computational processes. Our vision about energy-modulated computing that can be applicable for electronic systems with energy harvesting is introduced. Examples of analysis of computational circuits as loads on power sources are presented. We also draw inspiration from Heaviside's way of using and advancing mathematical methods from the needs of natural physical phenomena. A vivid example of Heavisidian approach to the use of mathematics is in employing series where they emerge out of the spatio-temporal view upon energy flows. Using series expressions, and types of natural discretization in space and time, we explain the processes of discharging a capacitive transmission line, first, through a constant resistor and, second, through a voltage controlled digital circuit. We show that event-based models, such as Petri nets with an explicit notion of causality inherent in them, can be instrumental in creating bridges between electromagnetics and computing.This article is part of the theme issue ‘Celebrating 125 years of Oliver Heaviside's ‘Electromagnetic Theory’’.

Advanced teaching method for balanced operations of overhead transmission lines based on simulations and experiment

An advanced teaching method for the analysis of balanced operations of overhead transmission lines has been described in this paper. The proposed educational method combines theoretical, simulation and experimental approaches with the purpose of a higher-level knowledge achievement. Several exercises have been defined and implemented in the teaching process. Some characteristic overhead transmission line steady state regimes, such as Ferranti effect, natural load flow and capacitive overhead transmission line behaviour, have been analysed. The special analysis has been carried out in order to determine the basic characteristics of the switching transients. Software package MATLAB/Simulink has been used for the estimation of system parameters and for the simulation analysis. Different overhead transmission line models have been compared and useful modelling guidelines have been recommended. Experimental calculations have been performed by using a physically scaled system consisting of multiple Pi sections representing 100 km length 400 kV overhead transmission line. The proposed method has been tested within High Voltage Engineering undergraduate course and useful application feedback from students has been obtained.

Development and analysis of a small-size electric field coupling wireless power system

This study intends to fabricate a small-size capacitive wireless transmission device. As to the design of electrode plates, the active electrode is designed in two ways, through row array and column array, and the area of an electrode plate is limited to below 20.25 cm2. Moreover, the passive electrode of row-array electrode plates is designed in three ways: general row array, window array, and rhombus array. As seen from the results of circuit simulation, the transmission efficiency of the capacitive wireless transmission device is as high as 0.7. In the actual circuit experiment, the electrode plate in the window-array design has the highest efficiency at 51%. In addition, the electrode plates in the window array and those in other arrays have higher stability and transmission efficiency. In the rotational angle dislocation experiment, the unit area current amount of the column-array electrode plates in the high coupling region is also smaller than that of the window-array electrode plates. However, the performance of column-array electrode plates reaches higher stability in the angle dislocation experiment, and its anti-angle dislocation is obviously higher than that of the electrode plates designed in the other three row arrays. Moreover, when the area of the column-array electrode plates is 22.25 cm2, the highest transmission distance is 22.5 mm.

An Optimal Reactive Power Control Strategy for a DFIG-Based Wind Farm to Damp the Sub-Synchronous Oscillation of a Power System

This study presents the auxiliary damping control with the reactive power loop on the rotor-side converter of doubly-fed induction generator (DFIG)-based wind farms to depress the sub-synchronous resonance oscillations in nearby turbogenerators. These generators are connected to a series capacitive compensation transmission system. First, the damping effect of the reactive power control of the DFIG-based wind farms was theoretically analyzed, and a transfer function between turbogenerator speed and the output reactive power of the wind farms was introduced to derive the analytical expression of the damping coefficient. The phase range to obtain positive damping was determined. Second, the PID phase compensation parameters of the auxiliary damping controller were optimized by a genetic algorithm to obtain the optimum damping in the entire subsynchronous frequency band. Finally, the validity and effectiveness of the proposed auxiliary damping control were demonstrated on a modified version of the IEEE first benchmark model by time domain simulation analysis with the use of DigSILENT/PowerFactory. Theoretical analysis and simulation results show that this derived damping factor expression and the condition of the positive damping can effectively analyze their impact on the system sub-synchronous oscillations, the proposed wind farms reactive power additional damping control strategy can provide the optimal damping effect over the whole sub-synchronous frequency band, and the control effect is better than the active power additional damping control strategy based on the power system stabilizator.

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.

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.

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.

Residual Compensation for Ground Impedance Relay With Applications in UHV Transmission Lines

The impedance algorithm in distance protection for high voltage (HV) and extra high voltage (EHV) lines, although neglecting the influence of shunt capacitance, is able to produce satisfactory performance. However, the accuracy of the algorithm is significantly reduced when applying to ultra high voltage (UHV) lines due to the larger P.U. line shunt capacitance and longer transmission radius. Therefore, the distributed parameter model should be adopted, and the relay should be set based on the hyperbola function between measuring impedance and the fault distance. However, how to define and set the indexes in relay ever defined with lumped parameters, such as the residual compensation coefficient, is still unresolved. In response to this question, the paper models the UHV system with distributed parameters and introduces the concept of virtual equivalent line length controlled by zero sequence system impedance, and then proposes a novel residual compensation coefficient. Case studies and RTDS tests show that the relay with proposed coefficient offers good performance for the simulated cases. The results also can be extended into other applications, such as the design of zero sequence reactance relay, fault location, fault phase selection, power swing blocking, and load blocking components.

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.

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

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.

Electrodeless thin film conductance measurements using the Sommer–Tanner method

A method to determine the electrical conductance of thin films such as a-Si:H that does not require contacting electrodes is presented. This method, introduced by Sommer and Tanner, is based on measuring the phase shift of a capacitive transmission line. The lower detection limit for the geometry used here is 10−11 Ω−1, which makes it suitable to determine the photoconductivity of a-Si:H thin films. The method shows reasonable agreement with classical conductance measurements using sputtered electrodes.

Coupling potentials in CA1 neurons during calcium-free-induced field burst activity

Small amplitude depolarizations (fast prepotentials, spikelets) recorded in mammalian neurons are thought to represent either dendritic action potentials or presynaptic action potentials attenuated by gap junctions. We have used whole-cell recordings in an in vitro calcium-free model of epilepsy to record spikelets from CA1 neurons of the rat hippocampus. It was found that spikelet appearance was closely correlated with the occurrence of dye coupling between pyramidal neurons, indicating that both phenomena share a common substrate. Spikelets were characterized according to waveform (amplitude and shape) and temporal occurrence. Spikelet amplitudes were found to be invariant with neuronal membrane potential, and their pattern of occurrence was indistinguishable from patterns of action potential firing in these cells. Voltage and current recordings revealed a spikelet waveform that was usually biphasic, comprised of a rapid depolarization followed by a slower hyperpolarization. Numerical differentiation of spike bursts resulted in waveforms similar to recorded spikelet sequences, while numerical integration of spikelets yielded waveforms that were indistinguishable from action potentials. Modification of spikelet waveforms by the potassium channel blocker tetraethylammonium chloride suggests that spikelets may arise from both resistive and capacitive transmission of presynaptic action potentials. Intracellular alkalinization and acidification brought about by perfusion with NH4Cl caused changes in spikelet frequency, consistent with reported alterations of field burst activity in this model of epilepsy. These results suggest that spikelets result from gap junctional communication, and may be important determinants of neuronal activity during seizure-like activity.

A trigger system using cathode read-out chambers and a coincidence matrix

We describe a system of cathode read-out multiwire proportional chambers which performed the trigger of the CERN NA3 experiment. These large chambers-the biggest measures 4.8 × 5.1 m 2-have been operated successfully since May, 1978. The cathodes are divided into about 1000 graphite cells painted on a mylar foil. The same cells are reproduced in silver paint on the other side of the mylar foil, which allows a capacitive transmission of the signals deposited on graphite cells. The signals are then transmitted to the amplifiers via copper strips which may be up to 2 m long. The amplifiers are currently operated with a sensitivity of 1 μA on 50 ω. A coincidence matrix, using fast ECL circuitry, uses the signals given by these chambers to select particles having large transverse momenta, in about 100 ns. This gives a very powerful trigger for the experiment studying high mass dimuon production by hadrons: about 60% of the triggers are true dimuons. An improved version of the coincidence matrix allows on-line selection of dimuons above a given invariant mass.

Dispersion of Nonlinear Elements as a Source of Electromagnetic Shock Structure (Letters)

Electromagnetic shock structure in nonlinear capacitance transmission lines can be resolved, and the energy losses associated with shock propagation explained, by including a resistance in series with the nonlinear capacitance. This resistance is inevitably present as the circuit representation of the nonvanishing relaxation time for the establishment of polarization in the nonlinear dielectric. Karbowiak and Freeman have dismissed this viewpoint as "not tenable!" This is a rebuttal of that statement.

Reduzierung der verschiebung des ruhepotentials bei kapazitiver impulsübertragung

The baseline shift accompanying capacitive transmission of pulses (up to 10 V amplitude, 200 ns width, 400 ns interval) is reduced to less than 3 mV, using a diode and an amplifier. The deviation from linearity is less than 0.1% for pulses of 10 mV up to 10 V.