I want to do a contactless reader by clrc663,but I need the antennas filed strength adjustable while range from 1.5A/m to 7.5A/m. Can you give me some advise to achieve this function?
1.5A/m to 7.5A/m is required in ISO specification, filed strength is only related to antenna, not NFC Chip. You needs to debug antenna to get the range.
