The common-mode current induced on cables attached to printed circuit boards can be a significant source of radiated emissions. Previous studies have shown that coupling from electric and magnetic field sources on circuit boards can be effectively modeled by placing equivalent voltage sources between the board and the cable. The amplitude of these equivalent sources can be estimated by using closed-form equations; however, estimates of the radiated emissions from these board-cable geometries have required full-wave simulations, and full-wave simulation results depend on the exact cable length and placement, which are not normally fixed during radiated emissions testing. This paper develops a closed-form equation to estimate the maximum radiated fields from a voltage source driving a board relative to an attached cable over a ground plane. This equation is evaluated for various cable and board geometries by comparing the calculated results to full-wave simulations. The maximum radiation calculated by using the closed-form expression generally predicts the peak full-wave simulation results within a few decibels for various board sizes and cable lengths.


Electrical and Computer Engineering

Keywords and Phrases

PCB Cable; Antenna Model; Cables (Electric); Closed-Form Equation; Common-Mode Current; Electromagnetic Interference; Equivalent Voltage Source; Maximum Radiated Emissions; Peak Full-Wave Simulation; Printed Circuit Board (PCB); Printed Circuits; Radiated Emission Testing

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version

Final Version

File Type





© 2008 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Feb 2008