> Microwaves aren’t RF.

Yes they are: https://en.wikipedia.org/wiki/Microwave_transmission

> The frequency has a very specific interaction with water.

No it doesn't: http://wtamu.edu/~cbaird/sq/2014/10/15/why-are-the-microwave...

Your link takes an award for missing the point. There is a resonant frequency of liquid water in the microwave range which is why tabletop microwaves use that range. They don’t emit a single frequency, no, but I don’t know anyone who claims they do...

> There is a resonant frequency of liquid water

Yes, I'll give you that

> in the microwave range

No. Water's first resonance is around 1THz, in the far infrared.

> which is why tabletop microwaves use that range.

No, they use 2.4GHz because that is what the FCC lets them use. The first microwave oven used 1GHz (https://www.google.com/patents/US2480679), later increased to 3GHz (https://www.google.com/patents/US2495429). Anything in that range will work.

You literally just wrote microwaves aren't radio frequencies, which is wrong by the very definitions of "microwave" and "radio frequency".

Different fields define the EM energy spectrum differently based on use. You can either argue that "microwave" is one end of the "RF spectrum", or that "microwave" and "radio" are two separate sub-categories of EM energy. My field teaches to the latter.

In the end it is an uninteresting point however because it is an argument over what word to use, not fundamental differences in nature. The point I was making earlier which was misinterpreted was that microwave interacts with matter in a fundamentally different way than lower frequency RF, which is critically important to the topic of TFA. Microwaves excite dipoles on the atomic and bio-molecular scale. Lower frequency RF requires some sort of conductive material (or A LOT of energy) to form an antenna, on the other hand, which is why we are transparent to "RF" but not "microwave" (and hence, why some fields treat them separately).

What is your field? What textbook says that "microwave" and "radio" are different? I've been citing a lot of sources here. Just this one from you would be appreciated.