Abstract: The principle of testing the shielding effectiveness (SE) of enclosures in reverberation chamber (RC) using frequency-stirred method is introduced briefly. Based on this, the shielding effectiveness of a slotted enclosure is measured. As to the low metering accuracy exposed in test, a combined stirring test technology is proposed, which can significantly increase the sample size in stirring bandwidth, thus reducing the uncertainty of test result. A new method based on digital low-pass filtering is presented to get the mean curves of electric field. The proposed method can effectively retain the peak information and obtain the desired smooth of electric field, so it enhances the accuracy of data processing. Compared with the two method, the combined stirring test method needs to combine mechanical stirring with frequency stirring, which is more suitable for large cavity test. The digital low-pass filtering is careless of the sample size and does not need additional test equipment.

Key words: ordnance science and technology, reverberation chamber, shielding effectiveness, frequency stirring, nested reverberation chamber, combined stirring