the antenna 2.4Ghz Could it’s work with 5Ghz And vice versa ?? and why ??
Antenna design is complex. (you can have a Phd in RF-transmission)
Any antenna not specifically “matched” to its intended purpose will not work at all, work very bad or even cause some damage because of the energy that cannot be radiated into the air that needs to be dissipated somewhere along the way.
Some interesting read just to give you an idea (yeah I know, Cisco links on a MT-forum but Cisco docs are often 1000x better organised)
Theoretically, Yes. If the wave lenght is half or double compare with the original designed wave lenght the transmitted power will be radiated with small amount of SWR. But it is a complex story!