A study of enclosure shielding effectiveness measurement using frequency stirring in a mode-stirred chamber

Frequency stirring is an alternative way to mechanical stirring to achieve statistical field uniformity in an over-moded chamber or enclosure, and has the potential to be used in the shielding effectiveness measurements (SE) of enclosures. A detailed study is presented in this paper to show aspects of the practical application of frequency stirring in SE measurement. Tests are conducted in a large enclosure (0.6 m * 0.7 m * 0.8 m) which allows different stirring approaches to be compared, whereas a small enclosure simulating a real computer case is used to investigate the stirring efficiency from the low frequency quasi-static to the over-moded higher frequency region. Factors influencing the measurement such as the mode density, stirring bandwidth and receiving antenna correction factor are also discussed.