Multiwire Transmission Line Research Articles

On the Features of Calculating Linear Parameters and Characteristics of Multi-Wire Transmission Lines

The features of calculating the matrices of linear parameters and characteristics of multi-wire transmission lines have been considered. The method of calculation of the matrices of primary linear parameters of multi-wire transmission lines has been presented. The criteria for the accuracy of the calculation of the capacitive matrix have been formulated. It has been noted that it is necessary to accurately account for the mutual influence between the transmission line conductors for a correct estimation of the distortions of thesignals propagated in it. The influence of the linear parameters of multi-wire transmission lines on responses and eye diagrams at the end of their active conductors has been demonstrated. The influence of the distances from the extreme conductors to the boundaries of the cross-sections of transmission lines on the accuracy ofcalculating their capacitive matrices has been studied. Using the method of moments, it has been shown that known approaches to determining these distances do not always give accurate or efficient results. On the example of several transmission lines with different numbers of dielectric layers and conductors, as well as with the screen and without it, the minimum values of this distance at which it is possible to achieve an accurate and efficient calculation of their capacitive matrices have been determined.

Consideration of Harmonic Distortions in Modeling the Electromagnetic Fields Generated by Power Lines Feeding Railway Traction Substations

In setting up intelligent electric networks, special attention is paid to the operational safety of electric power facilities and reduction of their negative impact on the personnel and environment. Significant electromagnetic field intensity levels can be observed at such objects. To ensure electromagnetic safety under the modern conditions characterized by large-scale introduction of digitalization tools, it is necessary to develop electromagnetic field digital modeling algorithms. Adequate models of the electromagnetic field generated by power transmission lines can be obtained on the basis of methods for determining the electric power system operation modes in phase coordinates. A methodology for analyzing electromagnetic safety has been developed on the basis of such models, which differs from the known approaches in being systematic, versatile, adequate to the external environment, and comprehensive. By using the newly developed methodology, it is possible to determine the intensity of electromagnetic fields generated by multi-wire transmission lines taking into account higher harmonic components of currents and voltages. Under the conditions of digitalizing the electric power industry, the use of the proposed methodology for practical applications will make it possible to analyze the conditions of electromagnetic safety in electric power systems on a scientifically sound basis and develop measures for its further improvment.

Multimode Propagation in 2-D Filters and Metamaterials

Metamaterials are characterized using a modal technique for the analysis of 2N -port 2-D filter networks. It will be shown that in general, all such networks support ${N}$ modes of propagation each with different propagation constants unless as with the TEM multiwire transmission line, the inductance matrix is the inverse of the capacitance matrix. Furthermore, a simple equivalent circuit for these 2N -port networks is derived, enabling complete network analysis for any combination of modal excitations. An explicit formula is derived for the propagation constants of a quasi-low-pass filter. This demonstrates that there are always ${N}$ modes even when the transverse network is infinite in extent.

High precision ultrasonic guided wave technique for inspection of power transmission line

Due to the merits of high inspection speed and long detecting distance, Ultrasonic Guided Wave(UGW) method has been commonly applied to the on-line maintenance of power transmission line. However, the guided wave propagation in this structure is very complicated, leading to the unfavorable defect localization accuracy. Aiming at this situation, a high precision UGW technique for inspection of local surface defect in power transmission line is proposed. The technique is realized by adopting a novel segmental piezoelectric ring transducer and transducer mounting scheme, combining with the comprehensive characterization of wave propagation and circumferential defect positioning with multiple piezoelectric elements. Firstly, the propagation path of guided waves in the multi-wires of transmission line under the proposed technique condition is investigated experimentally. Next, the wave velocities are calculated by dispersion curves and experiment test respectively, and from comparing of the two results, the guided wave mode propagated in transmission line is confirmed to be F(1,1) mode. Finally, the axial and circumferential positioning of local defective wires in transmission line are both achieved, by using multiple piezoelectric elements to surround the stands and send elastic waves into every single wire. The proposed research can play a role of guiding the development of highly effective UGW method and detecting system for multi-wire transmission line.

Wave propagation in a hybrid electric/magnetic four-wire transmission line system

The matrix theory of hybrid multiwire transmission lines has been laid very recently. Here, we consolidate this new subject by presenting analytical and numerical results concerning four-wire geometries. The examples offered address the interaction between a two-wire electric transmission line and a two-wire magnetic transmission line for the cases of coplanar, parallel, and perpendicular settings, where we show that mode coupling is observed only in the latter case.

Matrix theory of wave propagation in hybrid electric/magnetic multiwire transmission line systems

Matrix methods to deal with multimodal propagation in electric multiwire transmission lines are quite well known. However, the matrix theory of magnetic multiwire transmission lines (MMTL) has been established only very recently. In this study, we advance the new subject of hybrid electric and MMTL, which has never been addressed in the literature. A complex system composed of N + 1 electric wires and n + 1 magnetic wires is theoretically analyzed from the viewpoint of their interaction/coupling, transmission line matrix equations, ABCD matrix formalism, and superposition of propagation modes.

Frequency Analysis of Modal Distortions and its Application to Diagnostics of Electric Connections

The application of new physical phenomena often provides new quality of even simple structures comprising several conductors and dielectrics. Experiments proving decomposition of one pulse into several pulses of smaller amplitudes due to different mode delays in the structures have been performed [1]. An analysis of their results demonstrated the possibility of developing new devices for detection, identification, and diagnostics of multiwire structures; however, to implement the possibilities of these devices subjected to modal distortions, an analysis of the signal not only in time, but also in frequency domain is required. The purpose of the present study is to estimate the possibility of application of the frequency analysis of modal distortions to improve diagnostics of electric connections. The frequency of a signal minimum at the output from a section of a multiwire transmission line is [2]

Theoretical Approach to the Feasibility of Power-Line Communication in Aircrafts

In the domain of aeronautics, the future more electric aircraft will have to face a difficult issue related to the increasing number of wires and connectors, impacting on the weight and system reliability. A possible solution for solving at least part of this problem is to introduce power-line communication for specific applications. In this paper, the cabin lighting and communication system has been chosen as an initial scenario. Indeed, the tree-shaped architecture of the cabling is complicated enough to be representative of many other aircraft harness configurations. Channel characteristics are first determined from a propagation model based on the multiwire transmission-line theory. A software tool simulating PLC communication has been developed. By introducing the predicted channel transfer functions of different links into this software, the throughputs that can be reached, taking into account the electromagnetic constraints related to aeronautic standards, are discussed.

Treatment of arbitrarily-orientated multiwire bundles and terminated multiwire transmission lines in FDTD method

The finite-difference time-domain (FDTD) method is extremely versatile and widely used but there still remain structures in which the method encounters serious difficulties. One such situation is the analysis of bundles of closely spaced wires which are not parallel to the FDTD mesh. Similar problems are encountered in the analysis of multiconductor transmission lines such as PCB tracks. Recent research has yielded methods for treating single wires, orientated at an angle to the FDTD mesh, and for treating multiwire bundles which are aligned with the mesh, but not for both situations at once. In the paper, an enhanced method is presented which allows the treatment of wire bundles, including those which are arbitrarily orientated with respect to the mesh and those which may also be terminated with lumped components. Results are provided that show the consistency and accuracy of the proposed technique.

AN APPARENT ANOMALY IN TRANSMISSION LINE BOUNDING AND SOME OBSERVATIONS ON MULTICONDUCTOR PROBLEMS

ABSTRACT An apparent difficulty in developing bounds for transmission line systems is that lossy transmission lines have distortion. Three problems are presented for multiwire transmission lines that provide some insight into the possible bounding procedures and detail requirements for such line systems. This paper examines one of the constraints that has been used in the development of bounds, particularly upper bounds, for electromagnetic (EM) coupling and interaction problems. In addition, it discusses the modeling of multiconductor lines for bounding purposes.

Equivalent representation of multiwire transmission-line transformers and its applications to the design of hybrid networks

Aflshct-Lumped-element type equivalent representations of general multiwire transmission-line transformer3 containing ferrite torroids are presented. They are based on the physical model with cousideration of the mutual inductive couplings between all conductor segments of the winding wires. The concept of the mode of propagation is not used for the derivation of this representation. Signlficaut features of their Zn-port equivalent circuits are that they give transfer c%arwWWcs almost for all frequencies under any terminal conditions. So they are useful to the analysis aud the design of many kinds of the transformer circuits. As the applications, the design for hybrid networks cousistbqg of a trifilar wimling tramformer and Balun areexplained. Experimental results area heomparedwfth theory.

An Experimental and Theoretical Investigation of the Plane-Wave Excitation of a Multiwire Cable Harness

This paper examines, both experimentally and theoretically, the basic responses at the load ends of a cable harness when the cable harness is exposed to the excitation afforded by exposure to a TEM wave of a pulsed plane-wave array. The theoretical modeling involves the solutions to the appropriate time-dependent multiwire transmission-line equations using source terms reported by Taylor, Satterwhite, and Harrison. Two specific "cable bundles" were examined. One was a single wire harness, which provided a simple, well-defined geometry and resulted in the elimination of many uncertainties in the theoretical modeling appropriate for the experimental investigation. The other was an eight-wire, closely coupled, harness, that was representative of a typical satellite cable harness. In the case of the single-wire harness, the comparison between theory and experiment is excellent. For the case of the multiwire harness, the uncertainties associated with the important capacitance matrix, in particular the capacitance-to-ground of the various wires, effected an order-of-magnitude agreement in the theoretically predicted and experimentally observed responses at the load ends of the individual wires.

Simulating Cable Bundle SGEMP Excitation a Theoretical Feasibility Study

In this paper, the feasibility of simulating SGEMP threat-related responses at the loads of multiwire satellite cables is theoretically examined. Two basically different threat-related modes of excitation are considered. One involves generic photon excitation, both nonattenuated (or uniform) and attenuated. The second involves generic electromagnetic field excitation, both nonpropagating (or uniform) and propagating. The simulation technique which is considered for the photon-related response is capacitance pipe excitation; the corresponding technique which is considered for the electromagnetic field-related response is toroid excitation. The investigation uses the time dependent solutions of the multiwire transmission line equations which are coupled with the appropriate definitions of the pertinent current and/or voltage source terms. The results obtained from the prelusive feasibility study indicate that such simulation techniques could reproduce the responses afforded by the threat-related excitation.

Magnitude of Cross-Coupling Noise in Digital Multiwire Transmission Lines

Characteristics of a multiwire transmission line with inhomogeneous medium, as used for wiring in digital equipment, are investigated with respect to the cross-coupling noise, or cral. Formulas of crosstalk magnitudes are derived. Then they are simplifled for two specific kinds of transmission lines, i. e., a kind of strip lines and a line with equalized coupling. They are ready for straight-forward calculation by a computer, and agree with experimental results very well. A special kind of norm is introduced to simplify matrix calculations into scalar approximations to estimate a guaranteed upper bound of crosstalk voltages in the general case. It is found useful as a criterion in the first step of design considerations.

Basic nonuniform transmission lines

It is shown that for any given nonuniform transmission line (n.u.t.l.) ℒ, (which may be a multilayered RC network or a multiwire transmission line), with a per-unit-length series impedance Z(x) and shunt admittance Y(x), there always exists an electrically equivalent ‘inverse line’ ℒE, for which ZY is constant. Further, two more electrically equivalent lines may be found for which either Z or Y is constant. Although the study of any n.u.t.l. can be carried out directly, it is often advantageous to do so in terms of its equivalents. At present, the inverse line seems to be very attractive from a constructional point of view. It is also shown that for 2-wire lines, the different classes of n.u.t.l.s (including all their generalisations) known to have hyperbolic solutions are all equivalent to one of the ‘basic lines‘, namely the uniform line, the exponential line, the algebraic line z = z0(l + kx)±2, y = y0(l + kx)±2, the trigonometric line z = z0 cos ±2 (mx + n), y = y0 cos±2 (mx + n), or the hyperbolic line z = z0 cosh±2 (mx + n), y = y0 cosh±2 (mx + n). Thus, the study of networks containing n.u.t.l.s with hyperbolic solutions may be carried out in terms of these basic lines.

A Finite Series Solution of the Matrix Equation $AX - XB = C$

A Finite Series Solution of the Matrix Equation $AX - XB = C$