The NFC Antenna
The etched aluminium (or occasionally copper) antenna on the NFC Tag are technically not really antennas at all. They are really inductors designed to convert nearby magnetic fields into energy. The antenna is very carefully designed to resonate at the desired frequency of 13.56Mhz and ensure that this happens as efficiently and as effectively as possible.
The functionality of the antenna is not affected by it’s physical construction such as its thickness, which is why the ‘antennas’ within NFC tags can be very thin. However, the larger the antenna size around a powerful magnetic field, the better the performance.
Smart phones don’t produce much ‘power’, so there’s a limit to the optimum size of antenna. As such, you often get a decreasing performance as the antenna gets larger than the optimum size.
The weak point of an NFC tag is the bond – the connection point that joins the antenna and the tiny chip. His bond is likely to break if handled or bent too much.
More robust flexible have been successfully produced which means the bond will be able to withstand greater pressure so in theory, you could pass the Tag through a printing press.