Magnetic-Metallic board-level shielding hybrid solution evaluation

The continuous implementation of new advanced functionalities and the miniaturization of electronic devices has become a severe difficulty regarding electromagnetic compatibility (EMC). These requirements result in design restrictions that make using board-level shielding (BLS) techniques essential. The most common BLS solution is the metal shielding cabinet (also known as can) since it is widely used in printed circuit board (PCB) applications in order to provide local shielding of the devices that integrate the PCB. Generally, there are two reasons to introduce the BLS element: it can be required to provide isolation to or from other parts of the same PCB or nearby in the same electronic system. This contribution focuses on evaluating an alternative BLS solution based on combining a magnetic absorber sheet with an aluminum metal layer. This hybrid solution has the advantage of providing a shielding solution that does not require redesigning the electronics without a footprint or ground connection since it can be stuck over the EMI source. It is expected to obtain higher attenuation than using only a magnetic sheet by bringing the absorbing properties of the magnetic material and the losses mechanism of a metal, such as reflection and eddy current loss. The performance of the hybrid material is analyzed through two measurement setups: TEM cell and H near-field. The results presented show that the hybrid BLS provides a significant insertion loss compared to the magnetic absorber sheet.