nRF52820 PCB RF Design

RE: nRF52820 PCB RF Design

backstreet.devisor — Wed, 19 Jun 2024 14:05:31 GMT

I got it. Thank you so much for your help.

RE: nRF52820 PCB RF Design

JONATHAN LL — Wed, 19 Jun 2024 13:58:58 GMT

No other changes need to be made, its just that if you use L3 as the reference ground layer for the RF path then the thickness of the RF track will change slightly. So as long as you have accounted for that there is no additional steps.

PCB Antenna - How To Design, Measure And Tune

https://devzone.nordicsemi.com/guides/hardware-design-test-and-measuring/b/nrf5x/posts/general-pcb-design-guidelines-for-nrf52-series

Regards,
Jonathan

RE: nRF52820 PCB RF Design

backstreet.devisor — Wed, 19 Jun 2024 13:45:40 GMT

Hi. Thanks again.

What other changes need to be made to the calculations?

On the jlcpcb website there are no more additional parameters related to the ground reference layer.

RE: nRF52820 PCB RF Design

JONATHAN LL — Wed, 19 Jun 2024 13:35:06 GMT

[quote userid="112712" url="~/f/nordic-q-a/112120/nrf52820-pcb-rf-design/488882"]On the L3 layer I have 3.3V power supply tracks, but I fill the rest of the space with GND polygon. Can I also fill the space under the RF line with GND polygon on layer L3?[/quote]

Yes this can be done, but then you will have to adjust for this in the calculation of the RF path, but it is ok to do so.

Regards,
Jonathan

RE: nRF52820 PCB RF Design

backstreet.devisor — Fri, 14 Jun 2024 13:16:24 GMT

Thank you very much Jonathan for your reply. It makes sense to me now.

I have another question.
On the L3 layer I have 3.3V power supply tracks, but I fill the rest of the space with GND polygon. Can I also fill the space under the RF line with GND polygon on layer L3?

Thanks.

RE: nRF52820 PCB RF Design

JONATHAN LL — Fri, 14 Jun 2024 10:53:58 GMT

Hi,

Is L1 where you have the RF path\transmission line ?

If so then since you only have L2 as the GND plane then you should use that as the reference for the transmission line. So no cut out if you use L2 as reference GND. Fille the area with GND copper.

Reason we do have a cut out in our 4 layer designs is that we use the bottom layer as GND also and have that as the reference for the transmission line, this helps reduce any stray capacitance in the design.

Regards,
Jonathan