Interfacing 16 antennas to a mux to read an RFID TAG
Traditionally RF switching is done by a PIN diode switch like this one:



(Picture from this site)

Depending on wheteher the Diode is forward/backward biased RF passes through or not. You have to take care that biasing voltage is larger than RF peak voltage.

Several such switches can be used to multiplex several antennas to one transmitter/receiver.
E.g. like shown here.

There are also integerated circuits containing several diodes for such purposes.