Hi,
I'm designing a NFC antenna for my PN5180 PCD.
I'm doing this based on "AN11740 PN5180 Antenna design guide".
My question is about "4.2.1.6 Assembly and measurement " level.
Is this step( impedance measurement between TX1 and TX2 pins) done in live mode ?
I mean is it necessary to power on the PN5180 during the measurement or it must be powered off ?
There is Problem with my measurement, In both measurements(Initial Coil measurement and TX1/TX2 measurement) my parameters was not stable,It changes and also my smith diagram is a bit different with document.I used same ZVB20 VNA and it was well calibrated. Does any one have any suggestion whats problem and how could I fix it ?
I attached my first measurement smith chart( from antenna coil leads) During measurement values changes from 3~11 ohm in real part.
Dear Xia & Extephania,
Thank for Your replies.
I watched NXP NFC Antenna design webinars.
My question is if PN5180 must be powered off during impedance measurement between TX1 and TX2 pins, then why we does not de-solder the inductor L1,L2 which removes, PN5180 output pins effect on our measurement ?
This disconnect antenna circuit from from TX1 and TX2 pins which could change S11 parameter of antenna circuit.
Hello,
Maybe to help you understand better this topic, you can check the available webinars in the antenna design topic.
There are 6 of them and those might be good guidance on the topic.
Regards,
Estephania