PN5190 _Felica card transaction failure problem

[Clownfish_xl]

When using PN5190, we encountered a problem: when trading with Felica, there was a card. When the receiving data from the card was from 0cm to 3cm, it would time out. When the card was raised to 4cm, it could be traded normally.  May I ask if the original factory has any ideas to solve and analyze this problem? 

[renkebienert]

Can be many things...

Timeout looks like the card does not answer at all, i.e. either it did not get enough power or it did not understand the command.

I recommend a proper antenna design (based on NXP recommendations) and then a proper DPC calibration (based on NXP recommendations): Please check the related AN and webinar videos. Then everything should be working...