Almost all APs have two antennas, and looking at the design, it seems that the transceiver antenna is separated. Because it is duplex work, if you need to use an antenna, there should be something like a duplexer, and the practice of using a duplexer to reduce an antenna is not good for the reception sensitivity and the actual antenna transmit power. Some APs look like there is only one antenna on the outside, but in fact there are two antennas, but one is externally installed, and there is a simple point in the chassis, or simply made into a PCB antenna.