Different dielectric constants for rogers 4003C

Hi everybody,

I need to use rogers 4003C as a substrate for a pcb antenna but I am getting differing values for the dielectric constant when researching. Is it 3.38, 3.55, 3.6 or something else?
I know that dielectric constant can change with frequency but that is for FR4 and rogers 4003C should not be affected because it is a high frequency laminate?

Thanks!

Did you review the Rogers datasheet? Apparently different measurement methods result in different specifications.

There is a value they give you for design (er=3.55).

Yes, I did look at the datasheet but there were two, one for design and one for process, at different frequencies. I'm guessing to use the design one? But on internet suppliers are saying 3.4, 3.38, 3.6, 4.0... which is correct?

choose one that is close to your operating frequency. let's say er (or dk) at freq=1000MHz.