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NFC Antenna Inductance

Question asked by Circuit Sense on Apr 8, 2018
Latest reply on Apr 16, 2018 by Kan_Li

When measuring the inductance and resistance of a rectangular antenna for PN53x using a VNA like miniVNA

at what frequency should the parameters be measured ? 

 

A) 1 MHz

B) 13.56 MHz.

 

 

AN11535 the document says measure it at 1 MHz.

AN1445 says measure it at 1 MHz.

 

Slide 21 of this presentation says - 

The antenna loop has to be connected to an impedance or network analyser at 13.56 MHz to measure the series equivalent components

(http://miniradiosolutions.com/wp-content/uploads/2015/09/NFC-Reader-Design-II-Antenna-design-considerations-Public.pdf)

 

If I look at the NFC Antenna tuning video on NXP site the parameters measured are at 13.56 MHz.

(https://www.nxp.com/video/nfc-antenna-design-2-antenna-matching:ANTENNA-MATCHING-VIDEO)

 

 

 

I would like to know why the discrepancy ?? and what is the correct method.

 

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