> I smell a startup about to try for some more funding!
I rather smell some pretty bad science in your post.
Near field component of an RF field can be either magnetic or electric: it depends from the source type (electric dipole vs. current loop) and its polarization. IIRC some useful discussion on the topic can be found
here. The near field becomes negligible with respect to the propagating wavefield at a distance of a few wavelengths: if indeed they use 2.4 GHz for their device, either it isn't a near field device, or it does not work at 2.4 GHz.(I will resist to the temptation of posting my thoughts about the security of NFC technology here...)
I don't know where you found that water has a 2.4 GHz absorption band (Wikipedia ? ham radio literature ?!? I am curious...). To my knowledge water in the liquid state has a somehow broad absorption resonance at around 15 - 20 GHz. By the way, if water should resonate at 2.4 GHz, microwave ovens would burn meat on the surface, leaving the rest cooked rare! As a reference look at this
paper: RF attenuation is easily estimated from real and imaginary parts of the dielectric constant.
Flesh is a lossy dielectric body, and cannot be approximated with a poorly conducting metal surface, as you do when you write "this largely comes down to thermal effects in the skin and other surface layers". RF absorption inside the human body cannot be neglected, except maybe in the spectrum window between far infrared and UV-B regions.
51 (no more a radio amateur, since when I wanted to become a physicist...).
