A Simple, Non-Intrusive and Fast Measurement Method to Estimate Shielding Effectiveness of Planar Samples at High Frequencies

Shielding Effectiveness measurement techniques for shielded enclosures with apertures and shielding covers have been a topic of research for quite some time now. Minimizing the measurement time was achieved by transitioning from anechoic chambers to reverberation chambers. The nested reverberation chamber technique was then introduced, which has been well established over the years for doing shielding effectiveness measurements but requires multiple antennas and stirrers within the outer and inner chambers. Recent studies have sought to minimize the use of multiple antennas and stirrers within the inner chamber to measure the shielding effectiveness of physically small but electrically large enclosures of dimensions comparable to quarter of wavelength, as having sensors inside such enclosures is often difficult in more realistic scenarios at frequencies in the GHz range. This paper builds upon this line of thought and extends the method of estimating shielding effectiveness for electrically large enclosures to include material samples such as metal sheets with holes, ventilation ducts used in Faraday Cages and other such samples which are "imperfect" shields but are commonly employed in realistic scenarios.