20h-原则Effects of 20-H Rule and Shielding Vias on Electromagnetic Radiation From Printed Circuit Boards Huabo Chen, Student Member, IEEE, and Jiayuan Fang, Senior Member, IEEE Dept. of Electrical Engineering, University of California at Santa Cruz, Santa Cruz, CA 95064 Tel: (831)459-4283 Fax: (831)459-4289 Email: hbchen@cse.ucsc.edu Abstract: This paper investigates the effects of “20-H rule” and shielding vias on electromagnetic radiation from the printed circuits boards. Introduction As the operating frequency of electronic circuits continues to increase, today’ s package and printed circuit board designers face more radiation problem than ever before. The control of radiated emissions to make the package comply with radiation constraints is one of the most important aspects of the EMC study. ……