The answer is ...Yes.

A 3dB hybrid coupler can be used in both transmitters and receivers.

I remain,

The Old Soldering Gunslinger

Another question about 3db hybrid coupler.
there are 2 input port and 2 output port.
if I put at the receiver, the 2 input port go to radios or antennas?

Again, the answer would be yes...or perhaps depends.

For instance, you have one receiver and you wish to couple that receiver to two different antennas, two ports would go to antennas, one to the receiver and one would receive a reject load.

Two transmitters into one antenna the transmitters would go on two ports, the antenna on one of the other ports and a reject load capable of sinking half the Po of one transmitter on the fourth port.

In NTSC TV, a 3 dB hybrid is used to couple the visual and aural transmitters to the antenna.  In the case of older VHF transmitting antennas, each output port fed a different direction dipole array (as in East-West antenna on one feed and North-South on the other).

There really isn't sufficien t space to go into a 3 dB Hybrid coupler in a forum such as this.  IIRC, there is a rather broad discussion of hybrid couplers in the NAB engineering manual.

I remain,

The Old Soldering Gunslinger