Antenna matching network question

[wwwenrico]

Hi,

I'm designing a board with the ESP32.

I noticed that in the latest hardware guideline, I mean the version V 2.4, the matching network changed.

At chapter "2.1.5 RF" the document says:
"A PI-type matching network is essential for antenna matching in the circuit design.
C-L-C structure is recommended for the matching network."

That network has no decoupling capacitor between the antenna and the LNA_IN pin of the ESP32.

I've always seen one decoupling capacitor between antennas and RF chips.
The typical value of this capacitor is just a few pF and it does not alter the matching network.


QUESTION 1
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Are you guys aware that between the antenna and the ESP32 there isn't the decoupling capacitor?


QUESTION 2
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Have you ever tested C-L-C structure on the ESP32?


QUESTION 3
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All ESP32 modules have a matching network that is not a C-L-C PI-type network.
Why did you change the topology of the matching network after years of well established C-C-L topology.


Thanks,
Enrico Migliore

[WiFive]

QUESTION 2
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Have you ever tested C-L-C structure on the ESP32?


QUESTION 3
--------------
All ESP32 modules have a matching network that is not a C-L-C PI-type network.

The newer modules wrover-b and wroom-32d/u and pico use C-L-C

[wwwenrico]

Hi,

thank you for the answer.


DECOUPLING CAPACITOR
------------------------------
Are you aware that the antenna and the LNA input pin are not galvanic isolated?


thank you,
Enrico Migliore