Impedance calculation on a two layer board

[JJalling]

Hi,

Is it possible to get altium to calculate trace impedance on a two layer board? Is the only way, to insert a "dummy" plane in my layer stack, and use that as a reference?

Thanks in advance.

/Jonas

[free_electron]

you can't do controlled impedance unless there is a plane ....
besides it is a futile experiment for a double sided board. the dielectric is so thick you need gigantic traces to get anywhere.

[marshallh]

Yup, your 50ohm traces will have to be several mm wide on twolayer.. I've seen it done, but its not practical for most things.

[JJalling]

Yes, they are quite wide. According to my rough calculations, I need trace widths of about 1.3mm for 50ohm.
I'm using double-sided .5mm RO3003 for the antenna.

I guess I'll just put in a dummy plane then, and remember to remove it later on.
Thanks guys.

Br Jonas