Physical properties of frequency or regulation

[CalcYouLater]

Are different electrical frequencies allocated to specific applications because of their properties or to regulate the spectrum so that each assigned frequency range is unique to one entity?

I guess a related question is: Are we going higher in frequency ranges for things like automobile collision avoidance because we are running out of "room" or because it is advantageous to use a higher frequency like 70 GHz vs 20 GHz?

 

[meBigGuy]

Yes, Yes, and yes, all of the above. It just depends.

Higher frequencies provide more room/channels. For example, I can't think of any propagation advantages to 5GHz wireless. The transmitters and receivers are more expensive, and you need more power for the same area coverage. But higher frequencies allow tighter beams, which is useful for some applications. And for some applications the limited propagation is useful and the small efficient antennas are convienient. Different frequencies have different propagation characteristics so are useful for different things.

 

[Windadct]

There are also regulations - allowing only certain frequencies to be used for certain applications. So to gat a little more bandwidth (performance) the next allowed frequency may be much higher.