Options for SoC with on-board antenna and external antenna

[ElectricBananaHand]

Hi!

I am looking for a SoC that both has an on-board antenna as well as an external one. I have found this product: https://www.espressif.com/sites/default/files/documentation/esp32-s2-wroom_esp32-s2-wroom-i_datasheet_en.pdf
But here it seems like the position of the resistor determines wether which one it will use.

Here is also a link that uses a different model and here it says:
"Note: You can’t use the two antennas at the same time, so you can only have one connection for the antenna."
https://randomnerdtutorials.com/esp32-cam-connect-external-antenna/#:~:text=ARDUINO%20REVIEWS%20PROJECTS-,ESP32%2DCAM%20Connect%20External%20Antenna%20(Extend%20Wi%2DFi%20Coverage,servers%20and%20other%20connectivity%20problems.


So my question is, has anybody come across a SoC that has the logic to decide wether to use the external antenna or on-board depending on the signal strength?

Thank you!

[hans]

For those modules its more of a manufacturing decision to build a module with PCB or external antenna.

Many cheap RF SoCs only have a single antenna port. If you want to select during "run-time", you could use a SPDT RF switch to switch between either ports. Analog Devices has plenty of such devices, among others vendors. Do select one that can support the maximum transmit power, as some parts are limited to only +10dBm or so. Oh and some parts have real PITA supply rails.. but there are also parts that can run of regular 1.8V or 3.3V supplies

It does mean custom hardware so a custom board design though...

[MarkT]

By resistor you mean the 0 ohm link?  You'd need a PIN diode switch chip to take its place.  To add that requires adhering to microstrip design principles as RF doesn't tolerate impedance mismatch, especially for TX as VSWR mismatch can damage the transmitter in some cases.