Hello everyone,
In a recent project I implemented a PN7150. It is used as a simple reader, 14443 and 15693 (might drop this standard). From the board a commercial NFC antenna is connected with a short coax cable through a u.fl connection.
Now I am pretty happy for the most part. Our custom tag counterpart works as intended. But the 14443 tag cards we use somehow acts up. The range is about 5cm till it gets detected, but it is not recognized when moving closer than 1cm to the antenna. Making the emitted field stronger does not help either. Our antenna is 4 x 3cm big, almost as long as the tag card wide.
The matching circuit was calculated with the measurements of the antenna including cable.