NFC antenna question

[bob_zhang]

Our customer use PN7150. I test the antenna coil parameters. The Rcoil is 16.3ohm,is it a normal value?  Besides, the antenna coil locate on the battery, I see the L value change from 1.33uH(remove battery) to 1.2uH(with battery),what kind of influence lead to for the performance and what should we do?

[IvanRuiz]

Hello,

The antenna resistance value is not bad, normally a small value translates into more power to the antenna but taking care not to exceed max transmission current, whilst a bigger antenna impedance is recommended for battery-powered devices; please take a look to the antenna design app note for more information about this.

Regarding the antenna onto the battery, it would be helpful to have a material to isolate them, some recommendations are available in the antenna design videos for NFC.

Hope it helps you to comprehend.

BR,

Ivan.