coupling between antennas

hi

As a part of my project work I want to receive same (broadband) signal on two antennas without any amplitude or phase mismatch. I would like to know if it is possible to get fully coupled signals on two antennas spaced closely. What is the maximum coupling coefficient one can achieve practically for broadband antennas ? what is the minimum distance between broadband antennas to get fully coupled signals? does close spacing between antennas pose any other problems like gain or impedance variation?

thanx
pacman

Hi,
I can't tell you how far away the antennas have to be to get what you want, but I can tell you for sure that once you get them too close, i.e. one in each others near field, about few wavelengths or less, you will start seeing a definitive change in the impedance and in the radiation pattern, they will start working as an antenna array.
If they are very close, probably less than half a wavelength they will start acting as one antenna.

hi

I want each of the antenna to deliver the same signal to their respective receivers. So can i achieve this by placing them less than one fourth of the wavelength apart? will it work for broadband signals as well ?

thanx

It sounds strange trying to have the highly coupled antennas. Usually, one tries to reduce coupling between antennas in order to increase their performance. I think that if you have coupled antennas, you have a mismatch and the performance decreases.

If you want to reduce couplings, you can visit this link. There are many files:
https://www.edaboard.com/viewtopic.p...373&highlight=

Otherwise, can you explain further why you need coupled antennas?

Bye,

Pere

you cannot get the desirable impedance and gain when the antennas are kept closely. there wil be a change in antenna parameters due to coupling. placing antenna less than λ/4 also causes coupling. to get minimum coupling place antennas in maximum distance possible.

I have a mathcad program that will calculate antenna to antenna coupling, but for some reason the edaboard is not letting me upload either .mcd or .xmcd files. Anyone know how to do it?

these extension are not allowed here. just zip it or make a .rar file and upload that file.