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Regarding NFC design for a smart ticketing machine

Riyaz R
Intellectual 310 points


Hi guys,

            Can you tell me how the thickness of PCB depends on NFC antenna design? Are there any constraints for PCB design? If so how i can overcome such issues?

 

  • 0
    TI__Mastermind 44795 points

    Hi Riyaz,

    PCB thickness and copper weight will affect the inductance of the antenna coil, especially when you are using two sides of the PCB for the coil.  If the coil is only using one side of the PCB, the PCB thickness should not affect it, but a difference in copper weight would.  Heavier copper will provide a lower inductance.  Typical FR4 uses 1.5oz copper weight and flex PCB typical is 0.5oz copper.  On an FR4 PCB with 6 turns(3 on top, 3 on bottom), I see about 2uH.  With the exact same layout manufactured on flex PCB, I see about 4.2uH.  This additional inductance is mostly due to the reduced spacing between the top and bottom layer coils on flex PCB.

    Can you provide additional details about your PCB and antenna design?  I can help make some specific suggestions with more detail.  Thanks!

  • 0 in reply to Eddie LaCost
    Intellectual 310 points
    Hi Eddie,
    Thanks for your suggestions. I am using 1.6mm single side FR4 PCB. So what should be the typical inductance value i need to achieve for better resonance at 13.56 MHz? Also what should be the grounding considerations for better performance? Thanks!