Summary
International Symposium on Electromagnetic Compatibility
2014
Session Number:13P1-B
Session:
Number:13P1-B1
Imbalance Control by Open Stub for Reduction of Common-Mode Conversion at Differential Transmission Line Bend
Tohlu Matsushima, Osami Wada,
pp.-
Publication Date:2014/05/12
Online ISSN:2188-5079
Summary:
At a differential transmission line bend, a differential mode propagates in a differential transmission line is converted to a common mode due to asymmetry of the transmission line. The common mode conversion leads signal integrity problems. In this paper, the method to improve electric symmetry of the transmission line bend is proposed for reduction of the common mode conversion. The self capacitance and inductance of a line is different from those of another line. In order to fit those parameters, the narrowing signal line for increases of self inductance and placing a conductor shape of which is like stub are adopted to improve imbalance of transmission line bend. As a results, 20 dB of reduction of common mode excitation is obtained by optimization of signal line width and stub length. In addition, equivalent circuit model for the transmission line bend is proposed for evaluation of the reduction. The simulation results using proposed equivalent circuit model are good agreement with the results of 3D electromagnetic solver.