Transmission Line Effects Research Articles

Development of Ferrite-Enhanced Side-Type Inductively Coupled Plasma

A side-type inductively coupled plasma (ICP) reactor for large-area processing has been developed with the aid of ferromagnetic cores. A low-frequency operation with strong coupling to the plasma solved the problems occurring in conventional ICPs such as transmission line effect, capacitive coupling, low-power transfer efficiency, and inability to operate in a high-vacuum region. Using an auxiliary antenna, the additional electric field can be applied to the discharge center. The energy flux from the side sources toward the discharge center could be controlled by applying an additional electric field to the center using the auxiliary antenna on the quartz window. This result showed a drastic increase in the center density with a small amount of the auxiliary power and thus provided easy control of the spatial uniformity over 450 mm. An image of the ferrite ICP operated by single power is presented.

Dynamic analysis of wave energy converter by incorporating the effect of hydraulic transmission lines

A heaving-buoy wave energy converter equipped with hydraulic power take-off is studied in this paper. This wave energy converter system is divided into five subsystems: a heaving buoy, hydraulic pump, pipelines, non-return check valves and a hydraulic motor combined with an electric generator. A dynamic model was developed by considering the interactions between the subsystems in a state space form. The transient pressures caused by starting/stopping the buoy or closing/opening the check valves were predicted numerically using the established model. The simulation results show that transmission line dynamics play a dominant role in the studied wave energy converter system. The length of the pipeline will not only affect the amplitude of the transient pressures but also affect the converted power. The variation of the time-averaged converted electric power with the pipeline length is estimated using the simulation method for the buoy exposed to one irregular sea state. Finally, it is suggested how reduced power efficiency due to the pipelines may be ameliorated.

Ecological benefits of dc power transmission

The environmental effects of dc overhead transmission lines are examined. The major effects of ac and dc transmission lines are compared. Dc lines have advantages compared to ac lines in terms of electrical safety for people under the lines, biological effects, corona losses, and clearance width.

Direct measurement of the radiation resistance of a dipole antenna in the whistler/lower hybrid wave regime

An electrically short dipole antenna radiating high‐frequency waves is instrumented insuch a way as to directly measure its radiation impedance when immersed in a laboratoryplasma. By measuring both current and voltage at the radiating end, transmission lineeffects are largely eliminated, and extremely accurate results can be obtained. Initial resultsare presented for wave frequencies ranging from lower‐hybrid to whistler, for densityvarying from 2 × 10

Chain Matrix를 이용한 Twisted Cable의 EMP(Electromagnetic Pulse) 결합 해석

In this paper, we analyzed the EMP coupling for the nonuniform transmission lines, such as twisted cables, using the chain matrix algorithm and the multi-conductor analysis. The BLT method is widely used for the EMP coupling analysis of the transmission line, however, it is difficult to apply to the nonuniform transmission lines. In order to analyze the EMP coupling of nonuniform transmission lines, the whole nonuniform transmission line is divided into incremental uniform line sections of the finite numbers, and the coupling in each small sections is now summed up to get the EMP coupling effect of the entire nonuniform transmission line. To verify the proposed EMP coupling analysis method, the result of the EMP coupling simulation is compared with the solution of BLT equations for a uniform transmission line case. The proposed method is applied to the twisted cable over ground in case of being illuminated by the HEMP in order to analyze the EMP coupling.

Recording Front-End Systems Analysis

As data rates continue to increase, front-end design techniques and analysis must evolve in order to manage the transmission line effects and the parasitic effects of the transducer, electronics, and electrical interconnect. In addition, the complete write process contains linear and non-linear effects, which requires write signal wave-shaping for optimum performance. Data signal fidelity is maintained by proper termination at the read/write integrated circuit (IC), which is dependent on the read/write transducer's impedance range. For writing, transmission-line termination techniques along with the write-driver electronics are utilized to induce the required overshoot for transitions in the write current waveform. For reading, the key aspects of signal-to-noise ratio (SNR) and bandwidth are the parasitic components at the read transducer and the input at the read amplifier. The Noise Figure (NF) of the front-end system can be modeled to include the parasitic effects along with the transmission losses of the interconnect. Here, we expound on design techniques and component values for the front-end system.

Using Evolutionary Algorithms for Signal Integrity Assessment of High-Speed Data Buses

Today's high performance computer systems must have fast, reliable access to memory and I/O devices. Unfortunately, inter-symbol interference, transmission line effects and other noise sources can distort data transfers. Engineers must therefore determine if bus designs have signal integrity--i.e., can transfer data with minimal amplitude or timing distortion. One method of determining signal integrity on buses is to conduct a set of data transfers and measure various signal parameters at the receiver end. But the tests must be conducted with stressful test patterns that maximize noise to help identify any potential problems. In this paper we describe how an evolutionary algorithm was used to evolve test patterns for use in intrinsic testing.

The Effects of Electric Transmission Lines on Property Values: A Literature Review

This paper presents a review of empirical studies on the effects of electric transmissionlines on property values. The primary purpose of these studies is to address the effectsof the presence of transmission lines on the value of surrounding properties. Thestudies range from survey-based research that provides important context to regressionanalyses of sales data to less formal appraisal-based sales analyses. The surveys ofmarket participants and real estate professionals found evidence of concern and atleast in one survey, an assumption that such concern would impact property values.Others noted the unattractiveness of the transmission lines and structures. However,most of the regression-based sales price analyses found little or no effects on price.What effects that were found tended to dissipate with time and distance. Lastly, priceanalyses based on less formal paired sales and other techniques failed to find anyeffects.

Interfacial polarisation on gallium arsenide membranes

An investigation on the dielectric properties of gallium arsenide membranes is presented. Particularly, the authors exploit the interfacial polarisation effect of microstrip and coplanar transmission lines on multilayered membrane structures. Such structures are in favour with the Maxwell–Wagner polarisation, which can be used for resembling the dielectric characteristics of high-k materials. The authors demonstrate a technique for attaining large slowing factors while the corresponding dielectric losses are significantly reduced.

A high resolution Mirnov array for the Mega Ampere Spherical Tokamak

Over the past two decades, the increase in neutral-beam heating and alpha particle production in magnetically confined fusion plasmas has led to an increase in energetic particle driven mode activity, much of which has an electromagnetic signature which can be detected by the use of external Mirnov coils. Typically, the frequency and spatial wave number band of such oscillations increase with increasing injection energy, offering new challenges for diagnostic design. In particular, as the frequency approaches the megahertz range, care must be taken to model the stray capacitance of the coil, which limits the resonant frequency of the probe; model transmission line effects in the system, which if unchecked can produce system resonances; and minimize coil conductive shielding, so as to minimize skin currents which limit the frequency response of the coil. As well as optimizing the frequency response, the coils should also be positioned to confidently identify oscillations over a wide wave number band. This work, which draws on new techniques in stray capacitance modeling and coil positioning, is a case study of the outboard Mirnov array for high-frequency acquisition in the Mega Ampere Spherical Tokamak, and is intended as a roadmap for the design of high frequency, weak field strength magnetic diagnostics.

An Investigation into Magnetic Field Management under Power Transmission Lines using Delta Configurations

The increase of power demand has increased the need for transmitting huge amount of power over long dis- tances. Large transmission lines configurations with high voltage and current levels generate large values of electric and magnetic fields stresses which affect the humanbeing and the nearby objects located at ground surfaces. This has in turn prompted increased activity in the documentation of calculation techniques to accurately predict field strengths in isolated conducting bodies coupled to lines of all voltages and design configurations. Overhead transmission systems required strips of land to be designed as right-of-ways (R.O.W.). These strips of land are usually evaluated according to some aspects; the most important one is the operating effects of the energized line includ- ing magnetic and electric field effects. Therefore determination of the maximum value of the magnetic and electric field stress at ground surface is very necessary and important. It is always required to minimize the amount of land set for high voltage (or current) transmission facilities. This can be achieved by the reduction of the field stress at ground level which is also considered as the most object of efforts to minimize the field effects of such high voltage AC transmission lines. This paper investigates the effects of the transmission line towers configurations, on the mitigation of the induced mag- netic fields, around and near the transmission lines, of the 500 kV systems. The magnetic fields of the conventional 500 kV normal horizontal (flat) power transmission line configuration are compared with that of the normal delta, inverted delta, compact normal delta and compact inverted delta configurations, and in turn its effects on the right of way (R.O.W) distance around the transmission line. The obtained results show that, for compact normal delta, and full compact inverted delta configurations, the resultant magnetic fields produced are lower than that produced from the conventional flat line configuration.

Single-Junction Thermal Voltage Converters With Reduced Uncertainties at Frequencies up to 1 MHz

This paper presents a new realization of standards for ac-dc difference at voltages ranging from 1 to 4 V and frequencies of up to 1 MHz. This work has mainly been focused on improving the determination of the components of ac-dc difference that most significantly contributed to the uncertainty of the previous realization. These components are the ac-dc difference due to skin effect, transmission line effect, and the interaction between parasitic inductances and capacitances, which is described here as the L/C effect. As a result, combined 1 - sigma uncertainties as low as 4.3 muV/V at 1 MHz have been achieved.

Fast Methodology for Determining Eye Diagram Characteristics of Lossy Transmission Lines

As the speed of signal through an interconnection increases toward the multigigabit ranges, the effects of lossy transmission lines on the signal quality of printed circuit boards becomes a critical issue. To evaluate the eye diagram and thus the signal integrity in the modern digital systems, this paper proposes a fast methodology that employs only two anti-polarity one-bit data patterns instead of the pseudo-random bit sequence as input sources to simulate the worst-case eye diagram. Analytic expressions are derived for the impulse response of the lossy transmission lines due to the skin-effect loss, while the Kramers-Kronig relations are employed to deal with the noncausal problem related to the dielectric loss. Two design graphs that can be used to rapidly predict the eye diagram characteristics versus the conductive and dielectric losses are then constructed and based on which, the maximally usable length of transmission lines under a certain signal specification can be easily acquired. At last, the time-domain simulations and experiments are implemented to verify the exactitude of proposed concept.

Prediction of Metallic Conductor Voltage Owing to Electromagnetic Coupling Using Neuro Fuzzy Modeling

Electromagnetic interference effects of transmission lines on nearby metallic structures such as pipelines, communication lines, or railroads are a real problem, which can place both operator safety and structure integrity at risk. The level of these voltages can be reduced to a safe value in accordance with the IEEE standard 80 by designing a proper mitigation system. This paper presents a Fuzzy algorithm that can predict the level of the metallic conductor voltage. The model outlined in this paper is both fast and accurate and can accurately predict the voltage magnitude even with changing system parameters (soil resistivity, fault current, separation distance, mitigated or unmitigated system). Simulation results for three different scenarios, confirm the capability of the proposed Fuzzy system model in modeling and predicting the total voltage and are found to be in good agreement with data obtained from the CDEGS software.

Analysis of common‐mode effects in a dual‐polarized planar connected‐array antenna

An analysis is presented of the efficiency of a dual‐polarized planar connected‐array antenna, with particular reference to possible use in wideband focal‐plane‐array applications. The modeling approach is described, and the results of different numerical techniques are compared. The analysis includes the effects of transmission lines used to load the array at a groundplane. Different types of loading are compared including optimum single‐ended loading and optimum differential‐mode loading with short‐circuit and open‐circuit common‐mode terminations. The results indicate that high efficiency over useful bandwidths should be possible. In the case of differential‐mode loading, the efficiency may be reduced at certain frequencies due to resonances of common‐mode currents on the transmission lines. The current distributions on the array are analysed, and observations are made which may be useful for modified designs.

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.

Reflection Enhanced Compensation of Lossy Traces for Best Eye-Diagram Improvement Using High-Impedance Mismatch

As the signal rates increase toward the multigigabit range, the lossy effect of typical transmission lines on the signal quality of printed circuit boards has become a more and more significant issue. This paper introduces the concept of reflection gain resulted from the high-impedance mismatch to improve the eye diagram at the receiving end by inserting the inductance or high-impedance line between the signal trace and matched termination. A systematic design methodology is also proposed here to tell how to resolve the optimal high-impedance elements for the finest compensation efficiency. Moreover, with the optimal inductance, a design formula based on the circuit theory is derived accordingly to estimate the approximate length of high-impedance line and after that, the ultimate performance of this compensation method is also evaluated. Eventually, some experiments are imple mented to validate the design technique.

Effects of un-transposed UHV transmission line on fault analysis of power systems

The conventional fault analysis method based on symmetrical components supposes that the three-phase parameters of un-transposed transmission line are symmetrical in case of fault. The errors caused by the method with the symmetrical distributed parameter circuit model as the equivalent circuit of the un-transposed ultra high voltage(UHV) transmission line were studied under both normal operation and fault, and the corresponding problems arising were pointed out. By contrast with electromagnetic transient and power electronics(EMTPE) simulation results with the asymmetrical distributed parameter circuit model of un-transposed line, it is shown that the conventional method cannot show the existence of negative and zero sequences before fault happening and there are many errors on voltage and current after fault happening which are different with fault types. The error ranges of voltage and current are 2.13%–81.13% and −7.82%– −86.15%, respectively.

Improvements in Noise Suppression for I/O Circuits Using Embedded Planar Capacitors

The performance of embedded planar capacitors in noise suppression of input/output (I/O) circuits and improvements in board impedance profile have been investigated in this paper. Simultaneous switching noise (SSN) is a critical issue in today's systems and this paper shows performance improvements by introducing thin planar embedded capacitors in the board stack up. Measurement and modeling results by including the effects of transmission lines and the power ground plane pairs in the board stack up in the gigahertz range quantify the performance of the embedded capacitors.

Impedance Behavior of TiO2 Nanotubes Formed by Anodization in NaF Electrolytes

The impedance behavior of nanotubular self-organized porous (PTO) films with thickness of , pore diameter, and average spacing formed on titanium by anodization in solution was investigated and compared to the behavior of compact layers (CTO). At potentials close to the flatband potential , PTO had an apparent interfacial capacitance at that was greater than the capacitance of CTO. This effect, however, was not only related to the larger effective area of PTO. Differentiation between both surface conditions vanished both at potentials significantly higher than and with increasing test frequency to . These findings together with observations of appreciable frequency dispersion suggest that the pore walls are rich in deep-lying localized states, which become evident only at lower test frequencies and at potentials negative enough that depletion zones do not merge at pore walls. PTO did not show a transmission line effect at frequencies as high as . Model calculations based on pore dimensions and electrolyte conductivity predicted that those effects could only take place at much higher test frequencies, but the slow response of deeper states might impair observation anyway.