EMI sheilding

Skin Depth (aka Skin Effect)
as a Function of Frequency, Permeability, & Conductivity
https://rfcafe.com/references/electrical/skin-depth.htm

Skin Depth Calculator
https://rfcafe.com/references/calculators/skin-depth-calculator.htm

Conductor Bulk Resistivity & Skin Depths
https://rfcafe.com/references/electrical/cond-high-freq.htm