Summary
International Symposium on Electromagnetic Compatibility
2009
Session Number:21Q2
Session:
Number:21Q2-3
Reduction of Common-mode Radiation by Terminating Guard Trace with Resistors
T. Watanabe, T. Matsushima, Y. Toyota, O. Wada,
pp.97-100
Publication Date:2009/7/20
Online ISSN:2188-5079
Summary:
A microstrip structure with a narrow return plane generates large common-mode radiation. The guard trace attached near the signal line can reduce common-mode radiation. In general, the guard trace needs a lot of via connections to the return plane for keeping the guard trace grounded. The guard trace with long intervals of vias causes resonance and additional radiation. We propose a novel technique for maintaining low radiation by using only two vias at both ends of the guard trace and adding a termination resistor to the guard trace. It was found that the matched termination suppresses guard trace resonance most effectively through a circuit simulation and radiation measurement.