Hi everyone,
I'm working on a project that requires multiplexing 6 NFC antennas to a single NFC reader, such as the ST25R3916B. From my understanding, because the reader uses separate RFOx (TX) and RFIx (RX) lines for differential communication, I need to multiplex both RFOx and RFIx for each antenna.
The most cost-efficient and compact approach I can currently think of looks like this:
STM32 + ST25R3916B (RFOx/RFIx)
--> Matching Network
--> RF MUX
--> [optional EMC Filter]
--> Antenna
Alternatively, if I place the matching network after the multiplexer like this:
STM32 + ST25R3916B (RFOx/RFIx)
--> RF MUX
--> Matching Network
--> [optional EMC Filter]
--> Antenna
…then I would need two separate MUXes per antenna path (one for RFO, one for RFI), effectively doubling the number of switches, which significantly increases both cost and board space.
My questions:
Has anyone implemented method 1 (matching network before the MUX)?
Are there known issues (e.g., detuning, crosstalk, or signal loss)?
Are there better or more efficient ways to multiplex multiple antennas with differential TX/RX lines?
- Do you have any recommendations?
Thanks a lot in advance for any suggestions or shared experiences!
Best regards
