Frequency shift as a consequence of metal presence

[ASant.6]

Hello to all,

I would like to know what considerations and calculations i have to do to know the frequency shift as a consequence of the metal presence near the NFC/RFID antenna tag and also it is dependent of metal type and size of the tag. 

Thank you!

[Ulysses HERNIOSUS]

Hi ASant.6,

is your interest more on reader or tag side? Or is this a general physics question?

BR, Ulysses

[ASant.6]

Hello Ulysses I am interested on tag side, but is also a general physics question. I want to design a NFC tag and calculate the shifts taking in account the antenna size and amount of metal.

Thank you!

[Berenice BENVEGUDA]

Hello,

Your question is not easy to answer. General physic on this domain relies on Maxwell equations. The shift of the frequency depends on several parameters : the antenna size, the number of turns of the antenna, the distance between the metal and the metal area regarding the antenna area ... It requires electromagnetic simulations .. or good experiment !

we have a quick evaluation in an application note available on our web site : How to design an antenna chapter 3.5.3

I hope this helps you

Best Regards,

BB

[ASant.6]

Ill try both experiments and simulations.

Thank you so much,

Antonio