Communication distance of TRF7970ABP

Hamada -

which tag protocol and size of tag are you using? this is important detail to have in order to get to complete answer -

Otherwise, fundamentally, there are a few ways to increase the communication distance with that hardware alone.

1. If using only ISO15693 tags, you can retune the antenna to have a Q of ~16 versus ~8 that it has now (which accomodates all the protocols) - this will  help some, but it depends on size of the tag. What you need to consider is that the coupling factor between the antenna and the tag should be as close to 1 as you can get it.

2. you can modify the LaunchPad to put +5VDC on pin 1 of the boosterpack header , then modify the code to inform the reader IC that it is running from +5VDC instead of +3.3VDC (register 0x00 would need to go to 0x21 instead of the 0x20 value being sent now)

this would involve cutting the trace right where +3.3VDC is provided to Pin 1 of J1, then wiring from pin 5 of U2 or top of C7 to get +5VDC to that pin

3. disconnect onboard antenna, install a U.FL connector on the pads marked CN1, then attach larger tuned antenna (for your desired Q factor) to U.FL connector populated on CN1 pads

here is pic of doing this with a pulse W3579 antenna and 45mm x 45mm ISO15693 tag