Hello,
I'm currently creating my own custom board for NRF 52832.
I put everything together, but I can't detect my custom board through Bluetooth using the NRF connect app.
I'm using QFAA and QFAB QFN48 with DC/DC regulator setup.
Here I've attached the schematic of my custom board and all the components.
I'm new to designing an antenna for BLE. I believe there's something wrong with the antenna design.
Please let me know if there's anything wrong with this design.
Thank you!
Hi,
Can you share the layout files? GERBER format or PDF maybe?
If you are able to program and read\write to the device then something is working at least.
We also have guides: https://devzone.nordicsemi.com/guides/hardware-design-test-and-measuring/b/nrf5x/posts/general-pcb-design-guidelines-for-nrf52-series
And a video made with one of our engineers:
PCB Antenna - How To Design, Measure And Tune
Also we will help with schematic and layout review, all you need to to is submit a review request and share the schematic and layout files.
Feedback on the schematic you shared.
The antenna is missing its antenna matching network, so the antenna might not be tuned properly. 
In the layout it should follow the ref design, and specifically the radio section should follow the ref layout as deviation form this layout can cause issues with suppression of harmonics. Tuning might be needed to achieve the best performance.
Also it is recommended to short two of the GPIO pins to ground, pin 37 and 38.
Regards,
Jonathan
Hi Jonathan!
Thank you so much for the reply.
I'm not sure what you mean by layout file. I'm creating my CAD file using Rhino 7 software.
I have attached a pdf file for the schematic:NRF52832_cad_final_Design.pdf
Also, I used the AppCad program to calculate the dimension that is required for the antenna.
This is the result that I got: 
My PCB will be made out of 9-micron copper laminated on 25 microns Polyimide laminate.
Also, what is the reasoning for connecting GPIO pins(37 and 38) to the ground pin??
Please let me know what you think!
The schematic is only the conceptual electrical connections and does not match the physical layout. From the file that you share I suspect that this is also how the board looks?
Is it a singel copper plane, 1 layer on top of a substrate?
If this is the case then there is a high chanse that the antenna and radio will need to be tuned to work, so you are unlikely to see any successful radio communication. As it is important that the device has enough ground and that the grund is connected all over to shorten return paths and current loops.
So here is an example:
schematic
PCB layout: Red is top layer, Blue is bottom. 
Joseph said:Also, what is the reasoning for connecting GPIO pins(37 and 38) to the ground pin??
It removes an issue where unwanted noise could show up in the RF path.
Also see:https://www.youtube.com/watch?v=2oA4X3OTz0M
Regards,
Jonathan
Hi Jonathan,
I connected GPIO pins(37 and 38) to the ground and connected the capacitor in between the connections. Here is my modified PCB layout: 
Is it a singel copper plane, 1 layer on top of a substrate?
-> yes. It’s a single copper plane on top. However, if necessary, I can get two layers of double copper planes on top and bottom, and a substrate (PI) in between. Would that be better and easier for me?
This is the result that I got:
-> Also, Could you please verify if the width and length dimensions are correct to achieve a Z0 of 50 ohms?
Joseph said:Also, Could you please verify if the width and length dimensions are correct to achieve a Z0 of 50 ohms?
This formula used here is for a design that does have a copper plane as a reference ground, so it will not apply to your design as it is now. Since you only have one single layer. 
Joseph said:I connected GPIO pins(37 and 38) to the ground and connected the capacitor in between the connections. Here is my modified PCB layout:
You do not need the capacitors if you dont use the pins. You can just directly connect them to the center pad of the SOC
But, You need to use two layers here. AND vias that connect the top and bottom layer ground together. 
Pleas watch the videos I linked for context:
PCB Antenna - How To Design, Measure And Tune
https://www.youtube.com/watch?v=EEb_0dja8tE
019 Inverted-F PCB Antenna: How to tune PCB circuits using a NanoVNA
And more info:
https://www.altium.com/documentation/altium-designer/via-stitching-via-shielding-pcb?srsltid=AfmBOoqXT2HXxyukmmMcLh_el8hXIDx3KkTGP-mjaTmPZc-4FeyP5UWd
Feel free to ask more questions if things are unclear.
Regards,
Jonathan
