A new shielding evaluation setup for conductive O-rings is proposed. This setup consists of the holder with a groove to fix the O-ring position. There are two ways to apply O-rings in narrow gaps, cylinder-fixing and plane-fixing. With this holder shielding effects of the O-rings can be evaluated from 10 kHz to 1 GHz for both fixing types.

We calculated the shielding characteristic of a three-dimensional array of strip conductors by using the electric field integral equation method and its expansion to an array structure. From reflection coefficients, the effective permittivity of the array is calculated. The effective permittivity becomes negative in the frequency range above resonance, in which the electromagnetic waves travel through the material in an evanescent mode and the transmission coefficient becomes very small.