Do I need to define a cut-out area in the ground plane for IPEX connector

techtoys
Posts: 26
Joined: Sat Jun 01, 2019 11:11 am

Do I need to define a cut-out area in the ground plane for IPEX connector

Postby techtoys » Mon Mar 18, 2024 2:51 pm

Hi

I am using ESP32 S3 MINI 1U on a 4 layer PCB. The 2nd layer and the 3rd layer are ground plane.
My question is: do I need to define a cut-out area on these two ground planes underneath the IPEX connector on the MINI 1U module?

If yes, what is the dimension required?

John

liaifat85
Posts: 139
Joined: Wed Dec 06, 2023 2:46 pm

Re: Do I need to define a cut-out area in the ground plane for IPEX connector

Postby liaifat85 » Mon Mar 18, 2024 3:39 pm

In general, leaving a clearance of at least a few millimetres around the IPEX connector footprint should be sufficient. However, you can check the datasheet: https://www.espressif.com/sites/default ... eet_en.pdf

techtoys
Posts: 26
Joined: Sat Jun 01, 2019 11:11 am

Re: Do I need to define a cut-out area in the ground plane for IPEX connector

Postby techtoys » Tue Mar 19, 2024 2:47 am

Hi

I can find information of antenna placement for onboard antenna like attached. But that is for onboard PCB antenna. For IPEX I can't find anything similar. Maybe I have missed something?

John
Attachments
antenna_placement.png
https://docs.espressif.com/projects/esp-hardware-design-guidelines/en/latest/esp32s3/pcb-layout-design.html
antenna_placement.png (54.07 KiB) Viewed 521 times

techtoys
Posts: 26
Joined: Sat Jun 01, 2019 11:11 am

Re: Do I need to define a cut-out area in the ground plane for IPEX connector

Postby techtoys » Tue Mar 19, 2024 10:58 am

Hi

There is an indirect information borrowing from Nordic's nRF52840 EVK. Its layout is open to the public(in Altium Designer format). Attached please find two screen captures :
1. File "Nordic_nRF52840_EVK_Layout1.png" shows the normal 3D view. There is a ground polygon pour around the U.FL connector.
2. File "Nordic_nRF52840_EVK_Layout2.png" shows the 3D view with all 4 layers combined in one picture. There is ground cut-out for the 2nd and 3rd layers. The interesting part is on the 4th layer which shows a complete ground pour without any cut-out for the U.FL connector.

My guess is that: when the EPS32 S3 MINI 1U module is placed on a PCB (baseboard), there is no longer required to define any cut-out under the IPEX connector because the module itself has the necessary cut in the module itself. The U.FL/IPEX connector guarantees that it is a 50Ohm co-axial cable and connector structure to connect to an external antenna no matter there is a ground plane under the module or not.

Any body has experience/comment on it?

John
Attachments
Nordic_nRF52840_EVK_Layout2.png
Nordic_nRF52840_EVK_Layout2.png (269.73 KiB) Viewed 472 times
Nordic_nRF52840_EVK_Layout1.png
Nordic_nRF52840_EVK_Layout1.png (135.97 KiB) Viewed 472 times

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