Hello,
I created a sucessfull code for nRF5340-DK working with bluetooth, uart etc. I am using the Bluetooth NRF52 dongle
to test. When I upload the firmware to nRF-DK works perfectly, it's sending and receiving packets.
Then I created a customized board with an external antenna. This board has 32KHz Crystal.
The power supply is working well with 3.3volts
These are the related parts of schematics
The antenna's track width is 9.84mil and below is the rf grounded dieletric. This
track width was calculated by Altium Design and I used an external tools to confirm
if it was correct.
This is the stack-up of the first two layers. The board has four layers.
| Top Solder | Solder Resist | 0.010mm | |
| Top Layer | Copper | 0.018mm | Red |
| Dielectric 2 | FR-4 | 0.122mm | |
| GND | Copper | 0.018mm | Brown |
We don't have a Spectrum Analyser at our lab. We don't have tools to do RF simulations too.
In order to know if there is a problem with antenna circuit I removed the L6 and C27 and installed a wire.
I don't know if could work but I tried.
This image you can see the wire. Wire's lenght is 15mm
I tested again and is not working. I am open to hear suggestions.
I already tried to change from external crystal to internal RC as 32KHz generator. Didn't work.
Thanks,
