Shielding effectiveness measurements in resonant enclosure using mode-tuned and mode-stirred method

A comparison in determining the shielding effectiveness of resonant conductive enclosures, having apertures in a removable side wall, using mode-tuned and mode-stirred methods is introduced. The measurement setup was based on GTEM cell as a compact field-generating environment, capable of accommodating small enclosures as DUTs. The signal was fed into the GTEM cell, thus creating a controlled incident field impinging on the enclosure. The field level inside the exposed enclosure was collected as the output signal. Highly expressed resonances were attenuated by introducing the mechanical stirring into the enclosure, thus turning the inside of the enclosure into a reverberation chamber. Additionally, the resonant behavior of the enclosure was reduced by introducing the water containers within the enclosure volume as dissipative load, consequently lowering the enclosure Q factor. The results obtained using mode-tuned and mode-stirred method were in good agreement.