Hand-Assembled Cable Bundle Modeling for Crosstalk and Common-Mode Radiation Prediction (original) (raw)
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Common-mode radiation resulting from handassembled cable bundles on automotive platforms
2006 IEEE International Symposium on Electromagnetic Compatibility, 2006. EMC 2006., 2006
A statistical cable harness model is developed to account for the random disturbance of the wire positions along hand-assembled bundles. The non-uniform random bundles are modeled as n -cascaded segments of uniform multi-conductor transmission line. At each section, all wire positions are disturbed with random numbers obeying a Gaussian distribution. In addition, a spline interpolation function is used to improve the smoothness of wires winding along the bundle. The commonmode current distribution along the bundle calculated with SPICE is injected into a full-wave tool, e.g., FDTD, as impressed current sources. Thus, the full-vehicle electromagnetic emissions from the automotive harness can be predicted efficiently. The model has been experimentally validated with a controlled laboratory setup.
2003
This paper provides an experimental verification of analytical expressions for predicting radiated electromagnetic fields from straight interconnect cables carrying high-frequency currents. These analytical expressions are derived through two different models. The former model is based on the assumption that a radiating two-wire transmission line can be considered as two Hertzian dipoles, while in the latter one each radiating wire is treated as a chain of short radiating dipoles. The radiated field is calculated and measured at selected locations and the results are compared in order to verify the agreement among them. Different configurations (two parallel cables at various distances from a conducting ground plane) are considered.
Calculation of radiated electromagnetic fields from cables using time-domain simulation
IEEE Transactions on Electromagnetic Compatibility, 1994
Abstruct-Radiated electromagnetic fields are produced by currents in cables or transmission lines interconnecting various circuits. An elegant method of computing the resultant electromagnetic field, produced by several radiating current elements, is given. The current in each radiating cable is first found from a time-domain simulation algorithm and this may be a steadystate or transient current. The radiated field is then calculated by assuming a radiating transmission line can be treated as a chain of short radiating dipoles. The problems associated with the calculation of the near-zone term at low frequencies and the overall response near the radiator are clarified. The proposed technique is fully evaluated and compared with other methods.
Statistical Prediction of “Reasonable Worst-Case” Crosstalk in Cable Bundles
IEEE Transactions on Electromagnetic Compatibility, 2000
Worst-case estimates of crosstalk in cable bundles are useful for flagging potential problems, but may also flag problems that only occur very rarely, due to the random variation of wire positions and other characteristics of the harness. Prediction of crosstalk that may realistically occur requires statistical methods. Monte Carlo simulation techniques are often used to account for statistical variation, but are time consuming and do not provide intuition toward the cause of, or solution to, problems. Here, we investigate prediction of the statistically "reasonable worst-case" crosstalk by forming probability distributions using inductance and capacitance parameters from a single harness cross section and using lumped-element approximations for crosstalk that account for strong coupling within the harness when the circuit is electrically small. The accuracy of this technique was evaluated through comparison to simulation results using the random displacement spline interpolation method for multiple random instantiations of several harness configurations. Tests were performed while varying the size of the bundle, its height above the return plane, the value of load impedances, and the presence of a return wire. The reasonable worst-case crosstalk was estimated within about 5 dB or less in each case.
Measurement-Based Modeling and Worst-Case Estimation of Crosstalk Inside an Aircraft Cable Connector
IEEE Transactions on Electromagnetic Compatibility, 2014
Crosstalk within cable bundles can degrade system performance. In aircraft systems that use shielded twisted pairs, the crosstalk occurs primarily in the connector where individual signal wires are not shielded or twisted. In many cases, the parameters which determine crosstalk within the connector are unknown because the connector is closed and wires cannot be easily accessed. Expanding on prior research [14], a methodology for measuring coupling parameters and modeling crosstalk within aircraft cable connectors at low frequencies (<400 MHz) was developed. The values of mutual inductance and capacitance were extracted from measurements made with a vector network analyzer (VNA). The characteristics of the individual wires were extracted from VNAmeasured TDR response. The accuracy of the model was evaluated through comparison of simulated and measured results. Additionally, a closed-form solution was developed to estimate the worstcase envelope of the differential crosstalk. The calculated results match the measured peak values well. This worst-case crosstalk estimate allows effective evaluation of the impact of crosstalk within different connectors. The developed method can be effective for analyzing complex aircraft cable assemblies and connectors without requiring extensive knowledge of the assembly procedure.
Progress In Electromagnetics Research, 2006
The inductive effect of near-end crosstalk for a category five unshielded, twisted-pair cable has been verified using the electromagnetic topology simulation method. Crosstalk reduction and its dependency on such parameters as driving signals, circuit configuration and impedance, are studied. The simulation results are consistent with analytical analysis. Results show that the straightthrough, differential-generator, twisted-pair receptor model is the most effective configuration to control the near-end crosstalk level. This is due to the influences from both the neutralizing mutual inductance and the single current generator. The simulation results also show that electromagnetic topology-based predictions are valid only for cables that are electrically short. Simulations are carried out using a compaction scheme with a single equivalent circuit. As a result, the unshielded, twisted-pair cable portion of the circuit can be combined with a larger network for analyzing the overall response of the entire network system.
Rapid simulation of the statistical variation of crosstalk in cable harness bundles
2010
Abstract Accurate assessment of crosstalk problems in cable harnesses requires simulation methods that account for statistical variation in harness parameters. Use of the T-parameter method to rapidly estimate the statistical variation of crosstalk in cable harness bundles is outlined. Crosstalk is calculated by segmenting the harness into a cascade of equal length multi-conductor transmission lines (MTLs).
Prediction of radiated emissions from cables with multiple connections to a metal plane
2015 Asia-Pacific Symposium on Electromagnetic Compatibility (APEMC), 2015
The radiated emissions from a partially shielded cable mounted 5 cm above a metal plane have been found to be dominated by the emissions from the 5 cm vertical conductor segments, which connect the cable shield and the signal wires to the metal plane at various locations. An equivalent circuit model has been developed for predicting radiated emissions from the cable. As part of an extension from the developed model, an additional wire is included and pulled back in the test setup. The methodology of modeling is applied to this new setup by adding an additional transmission line for the wire against the metal plane, and by including the mutual inductance between the transmission lines, which accounts for the locations of the transmission lines. The predicted radiated emissions match the full-wave simulated radiated emissions, further validating the modelling technique that was previously developed. This modelling procedure can be used to determine if a system meets a given radiated emission specification before any actual testing is done. If the radiation is predicted to be excessive then design changes, such as additional filtering, can be modelled before the cabling is built to determine if the changes will allow the system to meet the radiated emissions specification before testing begins.
In this paper, a computational hybrid method (HM) is developed for calculating the radiated coupling on an electric cable due to external electromagnetic (EM) near-field (NF) perturbations. These sources of EM perturbation are placed at some mm of the cable proximity. The analytical approach for evaluating the voltage across the cable extremities in function of the NF aggression is proposed. The HM proposed is based on the combination of analytical coupling models and numerical methods or measured data associated to calculate the induced voltages on the cable. The model developed is tested and validated for different configurations of the perturbing source in the wide frequency band from 200 MHz to 2 GHz. The methodology was validated with measurements comprised of two electric cables in different positions.