I recently came across the idea that walls block high frequency signal but it allows low frequency signal. Could anyone explain what is the frequency response of walls and what factor in wall modifies the frequency?

  • 2
    \$\begingroup\$ This is more a question for physics.SE than here, I imagine. \$\endgroup\$
    – Hearth
    Oct 20, 2019 at 15:30
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    \$\begingroup\$ Physics and here, I'd imagine. \$\endgroup\$
    – JRE
    Oct 20, 2019 at 15:33
  • \$\begingroup\$ this question is a bit broad! I'm sure you've came up with the idea of reading up on radio wave absorption, so I'm not sure what specifically you're asking about here, RaHuL. \$\endgroup\$ Oct 20, 2019 at 16:25
  • \$\begingroup\$ Thanks a lot everyone for replying .......I studied about radio frequency how it is penetrating and how the radio wave moves out of antenna . In studying those stuff i came across this concept....,@MarcusMüller \$\endgroup\$
    – RaHuL
    Oct 20, 2019 at 16:45
  • \$\begingroup\$ how about examining the frequency response of WOOD? \$\endgroup\$ Oct 20, 2019 at 22:04

1 Answer 1


A short answer is that penetration depth of electromagnetic waves in a material is proportional to square root of resistivity, inversely proportional to square root of permeability and, most importantly for this context, inversely proportional to the square root of the frequency of the signal. (Reality is not quite this simple, but this is accurate enough model for figuring out the idea)

The penetration depth is defined as the depth in the material where intensity of the signal is attenuated to roughly 37% of the original value.

Thus the high frequencies are attenuated more, which you have observed as walls blocking them more than the lower frequencies.


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