EMI (electromagnetic interference) test procedures specify that long cables should be bundled at their center in some circumstances. The author investigates the effect of cable bundling using analytical models and measurements. He examines how cable bundle parameters such as length and "tightness'' can affect the repeatability of the measurement. Simple models of a bundled cable suggest that relatively small changes in the geometry of the bundle can significantly affect the common-mode cable current. Parameters such as length, tightness, location and the number of turns determine the impedance of the bundle. As the impedance of the cable bundle changes, the resonant frequency of the system shifts. This can result in large changes at the very frequencies where EMI problems are most likely to occur. It is also shown that lossy cables or cables with a lossy common-mode termination are less likely to be sensitive to minor changes in cable bundle parameters. The resonant peaks in a lossy system are smaller and cover a wider band of frequencies. Small shifts in the resonant frequency do not have as much of an impact on the currents induced at any one frequency.

Meeting Name

IEEE International Symposium on Electromagnetic Compatibility, 1990


Electrical and Computer Engineering

Keywords and Phrases

EMI Measurement Repeatability; EMI Test Procedures; Analytical Models; Cable Bundle Parameters; Cable Bundling; Cables (Electric); Common-Mode Cable Current; Electromagnetic Interference; Geometry; Impedance; Induced Currents; Length; Location; Lossy Cables; Lossy Common-Mode Termination; Lossy System; Number of Turns; Resonant Frequency; Tightness; Transmission Line Theory

Document Type

Article - Conference proceedings

Document Version

Final Version

File Type





© 1990 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Jan 1990