everyone who will use the EPS32 in Europe has to declare CE conformity. This means that ESP32 must be conform with the RADIO EQUIPMENT DIRECTIVE (RED) – 2014/53/EU. According R&TTE Article 3.2 the ESP32 has to comply with ETSI EN 300328.
We made this test at INTERTEK and have a severe problem with the spurious emission radiated according EN 300 328, i.e. with the 3rd harmonic wave:
Frequency (MHz) | MaxPeak (dBm) | CRMS (dBm) | Limit (dBm) | Margin (dB)
4824.220000 | -34.53 | --- | -30.00 | 4.53
7236.224375 | -33.60 | --- | -30.00 | 3.60
9648.608438 | -18.66 | --- | -30.00 |-11.34
12059.419688 | -38.77 | --- | -30.00 | 8.77
The 3rd harmonic shows approx. 15 dBm more output than all other harmonic waves.
What can we do to get rid of this issue and gain conformity with ETSI EN 300328?
Many thanks for every hint
Regards,
Oliver