Can the nrf52840 board also be made into a 2 layer pcb?

[hmihmi]

I need to match the 50 ohm impedance for antenna performance.
It would be easier to manufacture using 4 layers, but I'm planning to manufacture it in 2 layers due to cost issues.
When I calculated it with an impedance calculator when manufacturing in 2 layers, the width was too wide at about 3 mm.
When I searched for several boards, I saw a case where an nrf52840 board was manufactured in 2 layers.
However, the width was not as wide as 3 mm.
Is there any know-how to manufacture an nrf52840 board in 2 layers without reducing the Bluetooth antenna performance?
Is there a sample file of a PCB manufactured in 2 layers?
Thank you.

[Bendik Heiskel]

Hi,

3mm wide transmission line seem way to large. Whats the PCB thickness and transmission line type was used for the calculation?

Using a 1.6mm thick board, with standard FR-4 substrate the width of the conductor should be closer to 1.2mm:

 

Using a 2 layer board fine for the nRF52840, but if you are using the aQFN package you will not be able to use all of the inner row of pins, as it will not be possible to route them out while keeping a good ground layer under the SoC.

 

The nRF52840 dongle is a 2 layer PCB, you can use it as reference. The design files can be found here:
https://www.nordicsemi.com/Products/Development-hardware/nRF52840-Dongle/Download

 

Best regards,

Bendik