measure the dielectric constant of the ESP32-Wrover module

Will it be possible to measure the dielectric constant of the ESP32-Wrover module to know if it is FR4 or not? In case, one wants to know the characteristics of the original PCB antenna
9 Replies
Navadeep
Navadeep11mo ago
I don't think it's easy to do that practically. One thing you can check for is the board stackup from the fabrication files or in the design itself. By your intent to study characteristics, do you mean the antenna's frequency response? Have a look at this - it's pretty much standard evaluated design for the given stackup https://docs.espressif.com/projects/esp-hardware-design-guidelines/en/latest/esp32/pcb-layout-design.html (link updated)
Umesh Lokhande
Umesh Lokhande11mo ago
Thanks! My initial thought was just to avoid the use of an external antenna in a new design. Later, realized as you likely said it won't be an easy task, and Espressif may not share docs and details. So thought let's check with others in the community.
ShreeshaN
ShreeshaN11mo ago
Even FR4 have many grades with different coefficients
Umesh Lokhande
Umesh Lokhande11mo ago
yes, exactly. how can one know if at all possible without gerber files?
ShreeshaN
ShreeshaN11mo ago
And different PCB manufacturer provide their dielectric coefficients based on the lot of raw materials
Umesh Lokhande
Umesh Lokhande11mo ago
Good point! By the way, board thickness is 0.75-0.8mm
ShreeshaN
ShreeshaN11mo ago
Do you plan on doing RF tuning for antenna after board manufacturing? Otherwise best would be to do the RF antenna routing and calculation based on the PCB manufacturer FR4 dielectric coefficients
Joseph Ogbonna
Joseph Ogbonna11mo ago
I think he should speak with the manufacturer and ask them for guide on proper antenna tuning, to get best results
Petr Dvořák
Petr Dvořák11mo ago
@Umesh Lokhande Just finish the design, verify it with NanoVNA, for instance and if it fails, you will respin the board. Keep it simple!
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