I'm really new to this filed and don't know anything about antenna, please forget me if the question is stupid.
I have an nRF52 DK, I noticed the Bluetooth antenna on it is PCB antenna, so my question is
1) if I have to design my own, will it be hard or I can do the same on the development board?
2) or keep the same circuit design in the development board, but add an attached antenna, what specifications should I follow to pick the antenna?
And I know the NFC antenna on nRF 52 DK is not commercialized, so how do I find a replacement?
(we want to use NFC to do some cellphone authentication, like between a cellphone and nRF52, so the distance will be close, like 3-5cm, but inside a plastic enclosure)
Any suggestion will be helpful.
I recommend reading this blog post regarding general PCB design guidelines for the nRF52 series.
Specifically the section entitled "Antenna" is relevant to your question. You can choose between using a PCB antenna and a chip antenna (consider that the PCB antenna is cheaper as it is one less component), and if you choose PCB antenna there is a white paper called Quarterwave printed monopole antenna for 2.4GHz that explains how to design it.
Regarding the NFC antenna, the schematic for Nordic's NFC antenna is available on our website here in the download section under nRF52-DK hardware files and I have also attached it below. So, the easiest would just be to use this design and produce your own.
Note that you can send your PCB files to us for review before production. Just create a private ticket and attach the relevant files.
I hope this answers your questions!
About the PCB design review, does Nordic accept Eagle file?
Gerber files are preferred, but you can attach the Eagle files as well. In addition, we'll need PDF for schematics.
Just make a new, private ticket for the PCB design review.