ST25RU3993 Eval Stack-up

[FAghl.1]

I am wondering why it was necessary to use 6 layers PCB board for ST25RU3993 Evaluation board ? As outlined in the documentation, layers are as follow:

Top Layer - RF GND Layer - Power Layer- GND Layer Routing Layer -Bottom GND Layer.

I want to change the Stack-up to 4 layers (to be economical) as: Top-GND-Power-Bottom (for routing and ground pour) and I wanted to be sure I am not missing a technical point since doing the PCB in 4 layers is totally feasible. Can anyone point out what is the point of having 6 layers versus 4 layers?

Thanks

[Marcel Rossignol]

Hello,

the main reason for the 6 layer design is the better EMC behaviour of the board. ​

We wanted to be on the save side to pass the FCC certification and have choosen 6 layers.

Best regards,

Marcel