Impedance Matching between Two Antennas
Yes. The antennas should be matched. The TX is the load antenna. The RX is the source. The 50 ohm source will deliver maximum power to a 50 ohm load but not to any other impedance. It may be more power efficient to simply use a passive reflector, rather than a TX and RX antenna connected by coax. A flat plate reflector, angled just right, works surprisingly well.