Evaluation And Characterization Of Pcb Shielding Effectiveness In Near Field Region

PCB level shield cans had been widely used in electronic industry to mitigate electromagnetic interference and to comply with Electromagnetic Compatibility (EMC) standard. However, the thinner, smaller, and faster, operating up to Giga-Hertz range devices led to electromagnetic interference among traces and components. To the best of author’s knowledge, most of the shielding effectiveness in PCB level was done in far field evaluation. Thus, measurement method in near field for PCB level shielding effectiveness by using electromagnetic 3D scanner is proposed in this thesis. Several test boards were designed with different shields’ dimension, evaluated for shielding effectiveness. Comparable results between the measurement and simulation justified the reliability of the measurement method in near field. Besides that, the evaluation of the impact of shield’s characteristic such as shield’s height and thickness, were modeled through simulation. Results suggested that shielding effectiveness could be improved by having greater shield’s height with smaller ground via spacing in shielding ground tracks. With every step of 0.5 mm increase in shield’s height, shielding effectiveness can be improved by 1 dB. On the other hand, shielding effectiveness would be degraded by 0.5 dB for every step of 1 mm increase in ground via spacing. In addition, greater shield’s thickness can contribute better shielding effectiveness for operating frequency below 300 MHz