A multiplexer is a device that allows you to switch among two or more analog or digital input signals and forward the selected input into a single line. In RFID systems, a multiplexer allows you to use one reader to control more reader antennas, allowing greater area coverage at a lower cost than using additional readers.
The right option, however, depends on the application and the frequency used. SkyeTek offers the SkyePlus MXH and MXU antenna multiplexers to allow one reader to cover several read-points. Both the MXH and MXU can be equipped with four or eight antenna ports depending on the application requirements. You can control these multiplexers digitally through the reader module. ThingMagic offers a four port, stackable multiplexer, enabling its UHF M5e reader to support up to eight antennas. .
The German company FEIG offers an eight times multiplexer that facilitates switching between RFID antennas with an operating frequency of 13.56 MHz. With one multiplexer, a reader can operate several single antennas and gate solutions and it’s possible to connect additional multiplexers to further increase the number of antenna connections.
There are other products on the market. I have never seen a report putting these devices through their paces, so I cannot recommend one over another.
—Mark Roberti, Founder and Editor, RFID Journal