Does earth itself emit electromagnetic waves?
Yes, the earth emits electromagnetic radiation.

It emits infrared radiation with wavelengths of about 1 µm to 1 mm. This is heat, essentially, and much of it radiates into space:



Most if not all of the earth's rocks are radioactive (e.g. because of minerals containing isotopes in the uranium decay chain, such as potassium-40) and emit gamma radiation with wavelengths around $10^{-12}$ m. I'm not sure how much of this radiation would make it through the atmosphere. 

You said you're not interested in atmospheric phenomena, but I wonder what the relative contributions of subsurface and atmosphere (e.g. the auroral kilometric radiation), as well as manmade sources, would be to the total signature. The planets emit radio waves (ask a radio astronomer), but I suspect most of that energy is from their atmospheres, since Jupiter and Saturn are especially bright. This book by Vázquez, Pallé and Montañés Rodríguez (2010; Springer) looks like it might address some of this, e.g. in Chapter 4.