Is there are possible to let the ST25R95 reading distance be over 30cm?

[Lchan.1]

I am doing a project which requires ST25R95 reading distance operating about 30cm. I studied the EV kit of ST25R95 and implemented the circuit as a reference to design my system.Unfortuneately, the reading distance is still around 7cm. After several days of studying the AN5248 and tuning the STSW-ST25R003, I still can not get a breakthrough in a longer reading distance and better magnetic field performance. Is there any reference circuit design that I can study to enhance my design?

PS. VPS_TX is connected to 5V, it suppose output power at 230mW

reader antenna: Molex 1462360031

tag model: ST25TV-ESEAL

[Ulysses HERNIOSUS]

Hi LChan.1,

please see https://community.st.com/s/question/0D53W000006r47nSAA/st25r95-distance-range-output-power-inductor-as-antenna which should answer (most?) of your questions.

I think 30cm which the given antenna is really out of scope.

BR, Ulysses

[Lchan.1]

Thank you for answering my question. The link you provided did little help in finding a suitable antenna in my design. From the test report on (page 11)https://www.molex.com/pdm_docs/as/1462360001-AS.pdf

1462360031 could receive signal over 30cm. The NFC IC TRF7970 they use could merely output 200mV per reading cycle( ST25R95 could provide 230mV!!) Therefore, I thought ST25R95 could get a higher distance in my design but it seems I am still stuck in solving this problem.

[Ulysses HERNIOSUS]

Hi,

I read figure 6.1.4 as reaching ~90mm (=9cm) distance with a 75*45mm tag. Interpolating the diagram between 75*44 and 38*22.5 tag antenna I would expect an operating range in the 7 to 8cm area.

Not sure where you are reading 30cm???

At such small antenna I also don't expect a major performance boost by further increasing the output power, especially not when going from max 200mW to max 230mW.

Best Regards, Ulysses