Will ESP32-WROOM-32U be damaged if operated without an antenna?

[plajjd]

Is it possible to damage the 2.4 Ghz transmitter if I transmit WiFi or BLE packets on a WROOM-32U without an antenna connected?

Phil.

[ESP_Angus]

Hi Phil,

It can be damaged, and for this reason it is not recommended to any enable RF transmission without a suitable antenna connected.

Anecdotally, I ran an ESP32 without an antenna connected for a while (without noticing) and it seems to be fine. But this is not a guarantee that all such cases would be fine.


Angus

[plajjd]

Thank you, ESP_Angus. We have had similar results - meaning we have run without an antenna at various times without noticeable damage. But recently we noticed one unit that had unexpected (highly variable) RSSI readings - even with an antenna attached. Our theory is that the unit was operated without an antenna at some point in the past, and damage occurred that make its power output unpredictable.

[rosenrot]

Does this hold also for bluetooth only usage? I couldn't find this information in the esp32-wroom-32u datasheet.

[ESP_Sprite]

It's possibly less likely for BT-only use to cause any issues, but it's still not something that we designed or tested against so it can't be ruled out that it damages the ESP32.

[blobkat]

Can it also be damaged if I won't use the antenna at all? For example in the ESP32-POE-EA by Olimex, where I would use Ethernet instead of wireless connectivity.

[ESP_Sprite]

As long as you don't use any of the WiFi or BT functions, you should be OK.

[alexkanlis]

An ESP32-S3-WROOM-1U devkit has died on me today for this reason. A colleague of mine has connected it to my computer so I could develop code for it remotely and I didn't know it was a U version without a PCB antenna. And my colleague didn't know about it either. I flashed the code on Monday evening and it had connectivity issues and instability since the beginning but it was transmitting. Today it stopped. It can do network scans (Rx) but cannot connect to an AP nor it can be detected at wifi scans if I configured it as AP. I just received a picture of the device and realized what was wrong. I didn't believe it could be possible with such low transmission powers but it seems it is!