I’m relatively new to RFID technology and have encountered an issue I’d like to understand better. In our setup, the tag is fixed very close to the reader antenna (less than 10 mm). Tags based on the NXP ICODE SLIX perform reliably at this range, but Fujitsu MB89R119B tags exhibit poor performance and a noticeable dead zone where we need to read the tag.
After adjusting parameters, we found that reducing the modulation depth from the default 100% to a range between 10% and 30% significantly improves reliability.
Our working theory is that 100% modulation might cause overshoot, leading to an over-voltage condition—but this is speculative. Interestingly, the NXP ICODE SLIX works fine at close range regardless of modulation depth.
Has anyone encountered similar behavior or can provide insight into why modulation depth affects these tags differently?
The reader is a TRF790A based DLP RFID2 module.
