| Summary: | 博士 === 國立臺灣科技大學 === 電子工程系 === 90 === Fundamental EMI source mechanisms leading common-mode radiation from printed circuit boards (PCBs) by modeling the imperfect ground effect is investigated. The finite size ground trace is defined as imperfect ground that can be viewed as an inductance reactance. Once, the current following through the ground-return path that will cause voltage drop. The voltage drop is the EMI source mechanism that will cause the ground-return path itself to radiate as a wire antenna. The radiation emission in far zones from PCBs is obtained by treating lines on PCBs as transmission lines (TMLs) and calculating the far-field emission due to current distribution on lines. In this thesis, we presented three precise circuit model, based on traditional transmission line model, but it considers the finite size ground trace, to decompose the total current into differential-mode current and common-mode current. There are three different TMLs geometries namely: co-planar strips, parallel-plate strips and microstrips will be introduced to confirm the measurement results and calculating results.
|
|---|
