Does the use of microwave communication heat water particles?

[ronaldcaius]

TL;DR Summary

Have there been studies that measure the heat gain of air born water particles in the path of microwave communication systems?

As microwave communication systems send designated frequencies through the atmosphere, are water particles within the path of these systems agitated enough to increase their temperature?

 

[berkeman]

Welcome to PF.

As microwave communication systems send designated frequencies through the atmosphere, are water particles within the path of these systems agitated enough to increase their temperature?

Sure. It depends on the frequency of the microwaves, but for some (especially near the microwave oven band) there is some transfer of energy to the water molecules in the air.

What research have you done into this question? Can you post some links to the reading you've been doing about it? Thanks.

 

[renormalize]

TL;DR Summary: Have there been studies that measure the heat gain of air born water particles in the path of microwave communication systems?

As microwave communication systems send designated frequencies through the atmosphere, are water particles within the path of these systems agitated enough to increase their temperature?

Let me quote from the following PF post: https://www.physicsforums.com/threa...y-high-in-this-one-room.1053147/#post-6904755
"Even at $100\text{% RH}$, the attenuation at $2.45$ and $5\text{ GHz}$ is less than $10^{-2}\text{ dB/km}$ ..."
The propagation loss of microwaves is due both to scattering and absorption (heating). So even if a 1 kilowatt microwave beam could somehow avoid scattering and attenuate only by the heating of atmospheric moisture, only about 3 watts at most would be absorbed by that moisture in a 1 kilometer distance. Bottom line: there is negligible heat gain by atmospheric water even from high-power microwave propagation.

 

[berkeman]

Bottom line: there is negligible heat gain by atmospheric water even from high-power microwave propagation.

Interesting. I did not know it was that low, but it makes sense. Thanks.

 

[Baluncore]

I would not trust that conclusion, since without specifying the temperature, the absolute water content (g/m³) of the atmosphere at 100% RH is unknown. It can vary by a factor of 10. The authors need to specify temperature or absolute humidity, or they don't know what they are doing.

https://en.wikipedia.org/wiki/Humid..._humidity,_relative_humidity,_and_temperature