I an designing a mifare reader with MFRC630 chip. The reader antenna is supposed to be sitting inside a metal enclosure with an acrylic plate in front of it. When run the calibration routine in LPCD after everything is mounted inside, the reader antenna gets calibrated to its environment and no false interrupts are generated. But when i touch my mifare tag from the outside on the acrylic plate it doesn't get detected.
Then i tried removing the antenna out and running the calibration again on it in air and found that the same tag gets detected without any problem from 2cm away.
After some speculation i figured that the metal around the antenna inside the enclosure is causing the calibration to stop at a point where the field isn't strong enough to detect the card outside.
The acrylic plate is just 3mm thick.
Is there a way to enhance the detection range outside with the metal being in close proximity to the antenna.
Please suggest me some ideas in firmware/hardware or both.