Interleaving Cavity Resonances for Shielding Enhancement in Topologically Definable Spaces

Shielding enhancement can be obtained via resonance interleaving when applied to complex, layered shielded enclosures. Resonance interleaving assumes that the enclosure is subject to topological decomposition into weakly coupled separate regions. For each region a set of unperturbed resonances is found by eliminating outside coupling. Resonance interleaving is achieved by adjusting the geometries or boundary conditions on the separate regions to minimize overlapping of the unperturbed resonances of adjacent regions. It is shown mathematically how this reduces the energy transfer between adjacent regions. Various means of obtaining the unperturbed resonances so that interleaving can be performed are discussed. An example of the shielding effect is examined and from it a qualitative estimate of a ~ 12 dB shielding effectiveness increase over critical frequency intervals is made. It is noted that the cost of using this approach in designing enclosures is minimal, in that only small geometry changes may be sufficient, and the concept can be used to locate design problems in pre-existing designs.