Hi nordic team, could I get a review on my e ink mp3 player pcb, that uses the nrf5340 and the npm1300
here is the github link
Hi,
For the radio and antenna to work optimally you need a few more components and some correction in the layout to set it up for success. 
Above here is an example on what we like to see, the Z labels components are the matching components for the antenna and this can vary and change but the first components are what we want to see. This are the radio matching components and the nRF will preform verry poorly without.
The final values of the Z components as well as the placement will depend on multiple factors on being what antenna is used. We always recommend that customers follow the recommendations of the antenna manufacturer for best performance.
So for the antenna that is there now it looks to not fit according to the datasheet recommendations. 
From the datasheet it looks like you want more space for a larger trace on the "floating" end here. They also show to a matching network but no values listed so this will have to be tuned.
Also for the layout of the radio matching we recommend that you copy the ref design we have
The component placement is a bit far from the ANT pin it self and it is not connected as we prefer. 
We want the first cap here to be connected to the GND layer on the center pad directly and not to the remining top GND pour.
Also the HFXO and LFXO can use internal load caps so the external ones can be removed, but they can also just be left NC as well, but it will save you some PCB space if removed. 
For the nPM1300 try to copy the layout as as well, the placement and distance to many of the components are critical to its performance. 
this is from config 1. ref https://docs.nordicsemi.com/bundle/ps_npm1300/page/chapters/hw_layout/ref_circuitry/frontpage.html#ariaid-title2
We also have a guideline here https://docs.nordicsemi.com/bundle/nwp_050/page/WP/nwp_050/intro.html for the nPM13xx series.
The performance of it also depends on the devices components so have a look at options we have tested here https://docs.nordicsemi.com/bundle/nwp_050/page/WP/nwp_050/buck_inductor_selection.html
We also had a colab video a few years back talkin mostly about the antenna stuff but there are other bits of info as well in this video so its worth a look: https://www.youtube.com/watch?v=x1m8G8MAeUQ
https://www.johansontechnology.com/products/antennas/rf-antennas/ has a antenna selection guide, its worth a look to see what can fit your needs in this project here. There are also many other antennas providers but Johanson has a good selection guide.
Regards,
Jonathan
