Hi Ahmed

Take a look into Henry Ott book, Electromagnetic Compatibility Engineering (awesome book btw), chapter 6, you will get the formulas you are looking for.

good luck

Already, it is necessary to specify for which frequency you work and for which type of coupling (inductive or capacitive). in any case the decibel of the shielding is calculated from the transfer function.

cordially.

There are lots of texts quoting the Schelkunoff approach to shielding of materials which uses permittivity, permeability and conductivity of the materials. They give you the shielding of an infinite plane sheet of the material. These are mostly useless because the ultimate shielding performance you will achieve depends more on the geometry and detailed structure of your shield and the frequency than it does on the material itself. As long as your shield is a reasonable conductor forgat the material and look at its structure. A typical metal equipment enclosure will give you between 0dB and 60dB of shielding.

Thanks Babouri for your reply. I work on high frequency EM!!

and about your answer Marvin:

Do you mean that the structure is the most important part to be focused but the loading of the conductive filler and its characterstic properties are less useful?

There are many ref talk about the permittivity and permeability as good factors to locate or estimate the interference suppression of the EM, what do we say then?

Thanks so much for your helping

Are you designing a shield as I assumed or a shielding material?

Hi Marvin

I intend to prepare a shielding material

Thanks