Question on PCB thickness for RF circuit

[edaenrico]

Hi,

I have to route an RF circuit.

On a track of the PCB, there's a sinusoidal signal at 1.9 GHz.f

I'm gonna use ordinary FR4 substrate.

What would be the best thickness in terms of price and performances?


Thank you,
Enrico Migliore

 

[BigBoss]

1.6mm is standard and cheapest.But 1mm and 0.8mm can also be used with extra cost.

 

[FvM]

Performance with FR4 will be bad in the microwave range, independent of the substrate thickness. To achieve a specific impedance, you'll select a w/h ratio. Except for a cerrtain copper roughness and skin effect influence, the loss factor won't change with different h values.

 

[rf1008]

Performance with FR4 will be bad in the microwave range, independent of the substrate thickness. To achieve a specific impedance, you'll select a w/h ratio. Except for a cerrtain copper roughness and skin effect influence, the loss factor won't change with different h values.

Yes,Substrate thickness has an effect on trace impedance,you should keep a contant w/h ratio to meet your conatant impedance when change the sub thickness. Some simulation tools may help you,such as ADS,Appcad,etc.