The electric fields that couple traces on printed circuit boards to attached cables can generate common-mode currents that result in significant radiated emissions. Previous work has shown that these radiated emissions can be estimated based on the self-capacitances of the microstrip structures on a board . In general, the determination of these self-capacitances must be done numerically using three-dimensional static modeling software. In this paper, an approximate closed-form expression for the self-capacitance of microstrip traces is derived. This expression can be used to estimate the voltage-driven common-mode emissions from boards with various microstrip trace geometries. The expression also provides insight relative to the microstrip parameters that have the greatest effect on radiated emissions.
T. H. Hubing and H. Shim, "Derivation of a Closed-Form Approximate Expression for the Self-Capacitance of a Printed Circuit Board Trace," IEEE Transactions on Electromagnetic Compatibility, Institute of Electrical and Electronics Engineers (IEEE), Jan 2005.
The definitive version is available at https://doi.org/10.1109/TEMC.2005.859059
Electrical and Computer Engineering
Keywords and Phrases
Absolute Capacitance; Approximate Closed-Form Expression; Common-Mode Current; Electric Fields; Microstrip Traces; Printed Circuit Board Trace; Printed Circuits; Radiated Emissions; Self-Capacitance; Voltage-Driven Common-Mode Emissions; Voltage-Driven Radiation; Wire Antenna
International Standard Serial Number (ISSN)
Article - Journal
© 2005 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.