Wifi is 2.4GHz, which is remarkably close to the frequency that microwaves use to heat food. They use that frequency because the H-O bonds in water wobble when subjected to radio waves of that frequency, and in so doing, absorb it and heat up.
Microwaves typically use ~1kW, and AIUI typically attenuates to virtually nothing within ~20mm. Wifi uses considerably less power -- some mW; I forget the details -- which won't last long at all. So yeah, good luck with wifi. Note that Bluetooth also sits in the 2.4GHz band, so forget using that, too.
The Zero W doesn't do 5GHz, but I very much doubt that would work any better.