Measurements and Analysis of the Effects of the Edge on the Radiation from a Printed Circuit Board
|關鍵字:||微帶線;邊緣輻射;印刷電路板;Microstrip Line;Edge Effects;PCB|
當線路越接近PCB邊緣時亦會產生共模電流，我們可以使用grounded guard trace的方式作抑制。我們也驗證20H Rule的應用，其中說明了電路板上的電源面與接地面的邊緣會有邊際(Fringing)效應發生，所以需將接地面增加尺寸為厚度的20倍。|
The microstrip line is the basic and popular transmission line structure in the microwave circuit, because of its simple architecture, low cost, and easy to apply in the printed-circuit technology. This thesis investigates the impact on electromagnetic radiation from high-speed circuit board by the board edge effect. PCB traces routed near board edges and carrying high-speed signals are considered to contribute to EMI problems. The measurement results show that board edge does affect the EMI performance and EMI can be suppressed by increasing the distance between trace and board edge. The common-mode current occurs due to a trace near a printed circuit board edge; it can be suppressed by a grounded guard trace. We also verify the 20H-rule. On board with power and ground planes, the fringing field at the edges of the board is contained by increasing the edge of the ground plane size by 20 times the thickness of the dielectric substrate.
|Appears in Collections:||Thesis|