Δαφνη Ευτυχια Αρθουρος

While I was waiting for my prescription at my HMO, I got to thinking about "steel box" buildings (which that building is), and how they screw with cell phone reception by being (more or less) big, partially-effective Faraday cages. (I was standing by the window with my cell phone's antenna pointed outside, and I could establish a connection to read my email only intermittently. When I went further into the building to see the doctor, my phone's signal strength indicater went sharply down and it switched to analog mode, indicating that it was unable to connect to a digital tower. These effects were expected.)

I started wondering what happens to the waves/fields excluded from a Faraday cage. Does the cage act as a big antenna piping all signals to ground, the way I think it does? If I'm wrong about it being a Faraday cage (which I might be, considering that the openings between the girders are WAY larger than the wavelength my cell phone uses), is it just a "shadow" effect, where deep inside the building you're just in the shadows of too many girders? In either case, I figure (in my naive, non-physiscist, non-EE way) that there's got to be some induced current in the steel of the building, right? I wonder whether there's anything we could do with that current, even if it's only in the "Stupid Planet Tricks" class of application.