antenna-theory.com

[codedawg]

I'm trying to put together an NFC unit using a pn532 from NXP but I want to be able to use an antenna that doesn't have to be directly integrated on the PCB. My antenna theory is shaky at best.

My thoughts are to use a customized coaxial cable for the antenna. This would serve two main purposes:
1) Modularity: I can replace either the antenna, the board, or the cable
2) Remote capability: I can place the main board in a secure location, but allow the antenna to be located somewhere else.

Is there a limit to the length of the cable between the antenna and the chip since we're talking about low-power here? Or any other cons?

[admin]

The NFC frequency is pretty low - 13 MHz. So that cable can be about as long as you want. 1 meter would probably be ok. Just use 50 Ohm coax or something like that and you are fine. Cable length becomes an issue at higher frequencies when there is more loss per length.

Here's the NFC page for your reference:
http://www.antenna-theory.com/definitions/nfc-antenna.php

[codedawg]

Thank you!