Improved Shielding Effectiveness of Enclosures using Symmetrically Placed Metallic Posts

This paper presents a preliminary study of the shielding effectiveness of a rectangular enclosure with apertures, when metallic posts are placed inside it. An analytical formulation is developed for this purpose, whose results are in good agreement with full-wave simulations. The findings indicate that inclusion of posts inside an enclosure can shift its first resonance frequency towards higher side by about an octave, depending on the size and placement of posts. Moreover, the shielding effectiveness of enclosure with posts improves significantly up to the augmented first resonance frequency as compared to the empty one. The proposed method can easily be accomplished in the industry by using screw-posts to tune the resonance frequencies of enclosures and for the improvement in their shielding effectiveness.