Changes in a printed circuit board's absorption cross section due to proximity to walls in a reverberant environment

Knowledge of the absorption cross section (ACS) of a printed circuit board (PCB) is essential when defining an enclosure's shielding effectiveness as it will determine how a PCB affects the internal electromagnetic (EM) field inside the enclosure. In this paper we show how the ACS changes when a PCB is in the vicinity of the enclosure walls by making measurements in a small reverberation chamber. We find that when the PCB is perpendicular to the chamber wall different measurement positions have little effect on the ACS, even when the PCB is positioned close to the wall. However, placing the PCB parallel to the chamber wall did show some differences in ACS. This information could be useful when considering situations where PCBS are stacked together or close to enclosure walls when in a reverberant environment.