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BGeig.3
BGeig.3
Associate II
January 4, 2023
Question

What happens to antenna performance of the STM32WB5MMG when left and right side of Module is kept without pcb?

  • January 4, 2023
  • 3 replies
  • 2252 views

The datasheet of the STM32WB5MMG BLE module describes the placement of the module, as well as recommendations for the ground plane on the right side to the module:

- The module should be placed in the top left corner

- The ground plane should be kept free and provided with vias.

0693W00000Y7OZKQA3.png 0693W00000Y7OZjQAN.png

My question:

What influence does it have on the antenna performance if the board on which the module is mounted has a similar width like the module? I.e. that the board ends directly behind the module (on the left and right side)?

Similar to this board:

0693W00000Y7OdvQAF.jpgOther electronic components would be placed under the module in the red zone.

Or like the Arduino Nano33 (but without the pins next to the module):

0693W00000Y7OhEQAV.jpg 

Thank you very much :)

Regards

Benjamin

This topic has been closed for replies.

3 replies

David MOTSHAGEN
David MOTSHAGEN
ST Employee
January 5, 2023

Hello Benjamin.

I assume that you would follow the recommendation to cover all parts except the antenna by a ground plane. Nevertheless, from your description it is impossible to say if the antenna performance would be (much) worse.

We recommend copying the ST reference design as much as possible in terms of schematics and layout.

David.

BGeig.3
BGeig.3Author
Associate II
January 5, 2023

Is there specific infromation I could give you to make a more comprehensive statement?

Or is there information about the antenna used in the module?

I can't quite understand why the board has to be continued to the right of the module. For this reason, I cannot evaluate the impact of the missing board. To test this would take quite some time.

Unfortunately, I am restricted to the shape of the board (as slim as possible).

SFenw.3
SFenw.3
Visitor II
January 23, 2023

I have a similar concern. In the attached drawing (screenshot from the layout notes), what are the minimum values of X and Y that are supported? X is the distance from the right side of the module outwards; Y is the distance from the end of the module where the antenna is located, back towards the pins on the other short side of the module.

0693W00000Y8x2cQAB.png

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