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Electrical and Computer Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

1996

Common-Mode Radiation

Articles 1 - 3 of 3

Full-Text Articles in Electrical and Computer Engineering

Investigation Of Fundamental Emi Source Mechanisms Driving Common-Mode Radiation From Printed Circuit Boards With Attached Cables, David M. Hockanson, James L. Drewniak, Todd H. Hubing, Thomas Van Doren, Fei Sha, Michael J. Wilhelm Nov 1996

Investigation Of Fundamental Emi Source Mechanisms Driving Common-Mode Radiation From Printed Circuit Boards With Attached Cables, David M. Hockanson, James L. Drewniak, Todd H. Hubing, Thomas Van Doren, Fei Sha, Michael J. Wilhelm

Electrical and Computer Engineering Faculty Research & Creative Works

Fundamental EMI source mechanisms leading to common-mode radiation from printed circuit boards with attached cables are presented in this paper. Two primary EMI source mechanisms have been identified: one associated with a differential-mode voltage and another associated with a differential-mode current, both of which result in a common-mode current on an attached cable. These mechanisms can be used to relate printed circuit layout geometries to EMI sources. The two mechanisms are demonstrated through numerical and experimental results, and an example from a production printed-circuit design is presented.


Experimental And Numerical Investigations Of Fundamental Radiation Mechanisms In Pcb Designs With Attached Cables, David M. Hockanson, Cheung-Wei Lam, James L. Drewniak, Todd H. Hubing, Thomas Van Doren Aug 1996

Experimental And Numerical Investigations Of Fundamental Radiation Mechanisms In Pcb Designs With Attached Cables, David M. Hockanson, Cheung-Wei Lam, James L. Drewniak, Todd H. Hubing, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

Stacked-card and modules-on-backplane printed circuit board geometries are advantageous for conserving real-estate in many designs. Unfortunately, at high frequencies, current-driven noise sources may develop at the connector. The connector may effectively drive the daughter-card against the motherboard and attached cables, resulting in common-mode radiation. The connector geometry can be modified to reduce the level of the effective noise-source when high frequencies are routed between the mother-board and daughter-card. Current speeds and PCB board sizes result in geometries that are of significant dimensions in terms of wavelength at the upper frequency end of the signal spectrum. Geometries are then of sufficient …


Fdtd Modeling Of Common-Mode Radiation From Cables, David M. Hockanson, James L. Drewniak, Todd H. Hubing, Thomas Van Doren Aug 1996

Fdtd Modeling Of Common-Mode Radiation From Cables, David M. Hockanson, James L. Drewniak, Todd H. Hubing, Thomas Van Doren

Electrical and Computer Engineering Faculty Research & Creative Works

Radiation from cables attached to printed circuit boards and shielding enclosures is among the primary concerns in meeting FCC Class A and B limits. The finite-difference time-domain (FDTD) method can be employed to model radiation from printed circuit boards and shielding enclosures with complex geometries, but difficulties in modeling wires and cables of arbitrary radii are encountered. Modeling the wire by setting the axial component of the electric field to zero in the FDTD method results in an effective wire radius that is determined by the mesh discretization. Neglecting the wire radius in applications, such as electromagnetic interference (EMI) or …