This is a newbie question. I'm pretty sure of the answer, but I would like confirmation. I found this thread in this forum that came close to what I was looking for, but I think my question is different.
I want to shield against ingress of far field electromagnetic radiation. The material I'm working with provides good attenuation of electric fields at the required frequencies, but no magnetic shielding. I've been trying to determine if I need to incorporate magnetic shielding into my design. I'm pretty sure that because there's a fixed relationship between the electric and magnetic fields in a plane wave in free space (E/H = 377 ohm), if the electric field is attenuated, the magnetic field is also equally attenuated, and no magnetic shielding is needed. Do I have this right?