Greetings:
I am trying to design an external antenna for the TRF7960AEVM kit. I am having a lot of trouble with the magnetic field strength necessary to power the Tag-IT HF-I tags. According to the datasheets for a standard tag (RI-I17-114A-01) it requires a 110dBuA/m field to operate, or 10.19 weber/m^2. For a coil with radius of 7.5cm, in order to read this tag from 30cm away, it would need ~ 4.5 billion turns. (Using equations from Microchip AN710)
I noted that the tag in AN710 seems to require a lot less field strength to activate. (0.045uW/m^2 versus 10.19W/m^2)
I am a little short on wire right now. So if anyone could point me to an alternate or far more correct method of going about my design I would greatly appreciate it.
Thank you in advance;
Stew