I want to design an NFC device.
I plan to use ST25R3916B as the reader, as well as ST25DV64 and M24SR64 as tags.
I hope it can switch between different protocols in work, including ISO15693 and ISO14443.
When using the ISO15693 protocol, the communication distance is 50cm. When using the ISO14443 protocol, the communication distance is 10cm
I have read other related articles in the community. Can you help me check if there are any issues with my ideas
1. I plan to design two antennas to accommodate different protocols (20x20cm and 3.7x4.3cm)
2. The maximum antenna I can use is 20cm x 20cm. Can I achieve my target communication distance by adding some external circuits (filters, amplifiers)? Is it possible to encounter impedance matching issues when doing so? I see that the chip of the RF power amplifier is single ended, and I think it is not suitable for use in differential signals. Their resistance is usually 50 Ω.
3. Due to the fixed direction of the sensing area during use, specific antennas can be used to increase communication distance.
We look forward to your reply
