The FDTD (finite-difference time-domain) method is used for modeling EMI antenna geometries to anticipate EMI problems in high-speed digital designs. FDTD is well-suited to modeling large-scale geometries such as cables that might be driven against PCB ground planes as a result of a noise voltage that appears at the connector. Three specific cases are addressed herein including a simple cable driven against a PCB ground, coupling between a high-speed digital and I/O line that drives a cable against the PCB, and the finite impedance of the PCB reference plane that results in an effective noise source that drives the PCB ground against the cable. The FDTD modeling is compared with measurements. Guidelines for coupling to I/O lines, and a keep-out distance around the board periphery for high-speed digital lines can then be developed.

Meeting Name

IEEE International Symposium on Electromagnetic Compatibility (1999: May 17-21, Tokyo, Japan)


Electrical and Computer Engineering

Research Center/Lab(s)

Electromagnetic Compatibility (EMC) Laboratory

Keywords and Phrases

EMI Antennas; EMI Problems; FDTD Modelling; I/O Lines Coupling; PCB; Antenna Geometries; Antenna Theory; Antennas; Board Periphery; Electromagnetic Interference; Finite Difference Time-Domain Analysis; Finite Impedance; High-Speed Digital Designs; Keep-Out Distance; Printed Circuits; Reference Plane; Finite Difference Methods; Time Domain Analysis; Cables; Solid Modeling; Geometry; Large-Scale Systems; Voltage; Connectors; Impedance

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version

Final Version

File Type





© 1999 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 May 1999