ESP32-C3 Super Mini Antenna setup

[Oliver999Steele]

Hi Guys! Can anyone help me with this one?

I have an ESP32-C3 Super Mini dev board, and I need to get the external antenna working. I believe I have to move an SMD component to change from onboard antenna to external IPEX connector. Has anyone done this before? I have attached a photo of my board, and circled what I think is the component......a capacitor???? (Should be 0 Ohm resistor) - See photo attached

Here is a link for the board I am using: https://make.net.za/product/3me3065/
Can find anything online regarding this.

Cheers!!

[nabilbachroin]

Yes, the circled component is likely a 0-ohm antenna-selection link. With power off, move it toward the IPEX path and verify the pads with a continuity meter. Connect a 2.4 GHz, 50-ohm antenna before powering on. Do not enable both antenna paths.

Espressif RF guidance:
https://docs.espressif.com/projects/esp-hardware-design-guidelines/en/latest/esp32c3/schematic-checklist.html
https://docs.espressif.com/projects/esp-hardware-design-guidelines/en/latest/esp32c3/pcb-layout-design.html

[Bighoneypot]

Hi Oliver,

yes, your assumption is correct. To switch from the onboard ceramic/PCB antenna to the IPEX (U.FL) connector on the ESP32-C3 Super Mini, you need to reroute the RF output trace:

1. The circled component: It is either a 0-Ohm jumper resistor (or small coupling capacitor) acting as a selector link. Currently, it bridges the RF output trace to the onboard antenna.

2. How to switch it:

   • Desolder and carefully remove that 0402 SMD component.
   • You have two options:
     • Option A (Re-use/Rotate): Re-solder that component rotated 90 degrees so it connects the common RF trace pad directly to the center pin pad of the IPEX connector.
     • Option B (Solder Bridge - easier):

Remove the component completely, then create a tiny solder bridge (or use a single thin strand of copper wire / 0-Ohm 0402 resistor) bridging the common trace pad to the IPEX center pin pad.

3. Important: Make sure there is no leftover solder or bridge connecting to the old trace going to the onboard antenna, otherwise impedance mismatch will severely degrade your RF performance. Also, never transmit without an external antenna connected to the IPEX port to avoid damaging the RF PA.

Hope this helps!