Absorption Cross Section measurement of stacked PCBs in a reverberation chamber

The Absorption Cross Section (ACS) of Printed Circuit Boards (PCBs) can be used to help determine how PCBs affect the internal electromagnetic (EM) field in a shielded enclosure and thus the enclosure shielding effectiveness. Stacked PCBs inside densely populated enclosures may not have the same ACS as the sum of the individual PCBs due to 'shadowing' effects. In this paper ACS measurement results from stacked PCBs are presented. The results show that stacking the PCBs close together reduces the ACS and this effect is increased with a greater number of PCBs.