Does anybody know if we have a cross polarized antenna in a smartphone how the receive signal in the two ports usually combines? is using a 90 degree hybrid coupler a normal way to combine the signals that reach to the vertical and horizontal antenna components or is there any other common way to combine the received signals in the V/H ports?
I don't know, but if you combine antennas using a hybrid (coherently) then you turn them into an array antenna that has a different polar diagram to either of them and you don't necessarily improve coverage. If you add them together after detection (non-coherent) then you get the sum of the two antenna power diagrams, but not as much gain as would be possible coherently. The best way would be an adaptive combiner that adjusted the phasing and combined the two coherently to maximise the signal, but this is only possible if you have the signal there to begin with! You could however process each antenna separately then add them together coherently in the processor in lots of different processor paths at different phases and see which results in the largest signal (or any signal). This has a higher processor load but is the way lots of things work in modern systems.
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