RFID Antenna Multiplexing

Discussion in 'Wireless & RF Design' started by simpleprog, Feb 7, 2010.

  1. simpleprog

    Thread Starter New Member

    Feb 7, 2010
    Working on a project with RFID reader, tags, and antennas. I want to be able to scan through 50+ antennas and read any and all RFID tags that are within range.

    To do this i thought of using: 1 RFID reader, 16 multiplexers, counter, and the antennas.

    The idea was to connect the antennas to the multiplexers and have the counter or adder scan through all the antennas 1 by 1 to check for tags. This would then be fed to the RFID reader.

    The problem:
    If i try to connect more than 4 antennas the read distance goes down dramatically. It actually goes down 1/2 the distance with each additional antenna.

    Anyone have any suggestions on how i would be able to setup an array of antennas that feed info to 1 RFID reader?!
  2. retched

    AAC Fanatic!

    Dec 5, 2009
    Last edited: Feb 8, 2010
  3. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    What type of off-the-shelf multiplexer is going to work at those frequencies. I'd be concerned that I'd have problems even at 13.56MHz.

    From the original post I understand the purpose of the multiplexer concept is to avoid the case of multiple antenna connections - the OP was proposing that the multiplexer network allows the system to cycle sequentially from one antenna to the next. Presumably each antenna is located at a different position around some widely distributed area of interest - say if you were tracking the presence of RFID tagged books on the shelves in a library.

    It's more likely that the multiplexing system is degrading the performance rather than double terminating antennas. Although, it's not clear from simpleprog's final statement what setup they had actually tried as the first go proof of concept.

    Since the OP hasn't returned, it looks like we'll probably never get the whole story anyway......
    Last edited: Feb 9, 2010