Nrf5340 with NFC Reader Antenna

[edmcnicholas]

Hello I am using the ST25R3911B on a board with the nrf5340 and the customer is asking for both reader and tag support.  Would it be possible to use the same antenna for both?  I am using the nrf5340 as a tag backup even though i know the reader can act as a tag.  I have implemented the reader on another board with no issue but the antennas were not close to each other.  On this design they would be on the same face of the enclosure.

Thanks,

Ed

[JONATHAN LL]

Hi.

I am not a 100% sure that I understand what you are asking here. 

Are you wondering if you can have a single antenna connected to two NFC devices simultaneously? Or is the current setup to have the two antennas sandwiched on top of each other or next to one another and you want to optimize by removing one antenna and using one antenna for both?

You can use the same antenna for both Reader and Tag, so it would be technically possible to use a single antenna, but I an not sure how well it would work if you have the to MCU's connect there NFC pins together with no switch to toggle what MCU is connected to the antenna the time. 

Regards,
Jonathan

[edmcnicholas]

I am just trying to get both functions.  I dont think they would be in use in the same use case but it looks like i might need 2 antenna just to be safe.

[JONATHAN LL]

Could maybe implement some sort of switching mechanic with som logic that one of the MCU's control so that it would work with a single one, but not sure if this is recommended, could be som unforeseen issues when adding complexity. 

Regards,
Jonathan