Say I amt transmitting an RF signal from an antenna through a non-freespace medium (e.g. sand, water, cement) how can I go about calculating the absorption losses up to a certain depth level? I feel like this should be a fairly common and well-known equation, but I cannot seem to find it. Thanks all.

EDIT: For simplicity's sake I am assuming the wave is only traveling through a single medium, meaning reflection is not a concern.

  • \$\begingroup\$ Search for "Skin effect" formulae for loss vs frequency, depth and conductivity. Also, you really need to know the conductivity of the medium in question. \$\endgroup\$
    – user16324
    Oct 8, 2015 at 16:41
  • \$\begingroup\$ FYI, depending on the frequency, you might have worry about scattering as well. \$\endgroup\$ Oct 8, 2015 at 16:42
  • \$\begingroup\$ When a radio signal is traveling through free-space and it encounters a change in media, you also need to worry about reflection, not just absorption in the new media. Just something to be aware of. Also, when you say "cement," I am guessing you mean "concrete." If the concrete is reinforced with steel bar, as most structural concrete is, it will probably act as a very strong screen for the RF radiation (depending on details of wavelength, etc). \$\endgroup\$
    – user57037
    Oct 8, 2015 at 16:42
  • \$\begingroup\$ Googlle "RF absorption" and find a table which deals with your proposed frequency and medium. Then do the math. \$\endgroup\$ Oct 8, 2015 at 17:22
  • \$\begingroup\$ The lower the frequency the better - you should be able to find an answer I made on this very subject somewhere lurking in EE. Here is one link: electronics.stackexchange.com/questions/174075/rf-communication/… \$\endgroup\$
    – Andy aka
    Oct 8, 2015 at 17:58


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