Hi, I plan on designing a NFC reader based on the ST25R3916B, with an "extended" range.
So, the antenna will be a 150 mm x 150 mm PCB antenna, 2 turns, 1 mm traces and 1 mm gap.
According to ST's NFC Inductance tool, this should yield an inductance of ~ 2.4 µH. I have modeled it with a better approximation of its real shape, using FastHenry3, and get ~ 2.1 µH @ 13.56 MHz. Not too far away. I suppose FastHenry does a more accurate analysis, but does not model dielectric, so maybe that's what explains the discrepancy?
My question is more about the antenna's shape. I will be driving it in differential mode, and am not 100% sure if the coil I have designed (see below) will work well as a differential antenna. Can you let me know or give me pointers if it needs some adjustments as to how the turns should be layed out?
Thanks!
