antenna matching with hybrid couplers

dear friends

what are the design constraints of matching two antennas with hybrid coupler. one output port connected to one antenna and the other output connected to another one.

---------- Post added at 05:38 ---------- Previous post was at 05:37 ----------

if hybrid coupler is matched to 50ohm load and antennas are also matched to 50ohm load, can we connect the antenna and hybrid coupler directly without having matching network in between them.

The main issue is that most of the hybrid couplers, if don't see a perfect resistive impedance (usually 50 ohms) at all terminated ports, their isolation change a lot.
And there is almost impossible to get a perfect resistive input impedance to an antenna.

could u tell me what sort of matching could be done then?

This depends what antenna you are using and how far its impedance is from the coupler impedance.
Any kind of matching will help, instead not using any. A simple matching network provides good match at least for one frequency.