I am currently designing an NFC reader in the context of my PhD thesis. The NFC reader will use a PN532 chip from NXP (which is one of the requirements of my circuit). I plan to draw a rectangular loop inductor on the PCB (which is often referred to as an NFC antenna in wireless design) which would approximately occupy a 3x3 cm square (up to 4x4 cm). There will be other components on this PCB such as an LED driver, some LEDs, etc. The main micro-controller will stand on a separate PCB and will communicate with this board through an SPI link. Space is the main constraint: the volume occupied by the PCB has to be minimized as much as possible.
I read this document quite carefully (NXP Antenna Design Guide) and I have very specific questions related to the design of the PCB that will carry the NFC controller and antenna:
- Could it be acceptable to put the components (NFC controller, LED driver) on the same PCB as the NFC antenna?
- What would be the "best" position relatively to the antenna in this case? (i.e. one that would limit eddy currents and inductance increase)
- How to efficiently shield the main controller board? Will a sheet of copper do the job (instead of ferrite)?
- Is there an advantage to have different length and width for the antenna?