Electromagnetic interference (EMI) filters are often utilized on I/O lines to reduce high-frequency noise form being conducted off the printed circuit board (PCB) and causing EMI problems. The filtering performance is often compromised at high frequencies due to parasitics associated with the filter itself, or the PCB layout and interconnects. Finite difference time domain (FDTD) modeling can be used to quantify the effect of PCB layout and interconnects, as well as filter type, on the EMI performance of I/O line filtering. FDTD modeling of a T-type and π-type filter consisting of surface-mount ferrites and capacitors is considered herein. The FDTD method is applied to model PCB layout and interconnect features, as well as the lumped element components, including the nonlinear characteristics of ferrite surface-mount parts. The EMI filters with ferrites are included in the modeling by incorporating the time-domain Y-parameters of the two-port network into the FDTD time-marching equations. Good agreement between the FDTD modeling and S-parameter measurements supports the new FDTD algorithm for incorporating two-port networks.


Electrical and Computer Engineering

Research Center/Lab(s)

Electromagnetic Compatibility (EMC) Laboratory

Keywords and Phrases

[pi]-Type Filter; EMI Performance; FDTD Method; FDTD Modeling; FDTD Time-Marching Equations; I/O Line EMI Filtering Design; PCB Interconnects; PCB Layout; S-Parameter Measurements; S-Parameters; T-Type Filter; Electromagnetic Interference; Filtering Performance; Finite Difference Time Domain; High-Frequency Noise Reduction; Interference Suppression; Lumped Element Components; Nonlinear Characteristics; Nonlinear Network Synthesis; Parasitics; Passive Filters; Passive Networks; Pi; Printed Circuit Board; Printed Circuits; Surface-Mount Capacitors; Surface-Mount Ferrites; Time-Domain Y-Parameters; Two-Port Network; Two-Port Networks; Finite Difference Time Domain (FDTD) Method; Generalized Pencil-of-Function (GPOF); I/O Filter

International Standard Serial Number (ISSN)

0018-9375; 1558-187X

Document Type

Article - Journal

Document Version

Final Version

File Type





© 2002 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Feb 2002