I am trying to make one page that contain all the useful information about NFC Antenna Design. I will keep update and add the information to this page when I found something useful.
First of all, there are 6 webinars about NFC Antenna Design. It is a good training before to start your antenna design for NFC.
Training & Events | NXP (Search "Antenna design")
PN5180 Antenna design tools(REV 1.2)