Transmission line impedance

Hello all,

My question is ?
I have seen in may standards quoting transmission line impedance equal to 1.5pF per cm . How this number is calculated?
Is this value frequency dependent? transition dependent ?

Kindly help.
Suggest link to know more information about the same.

Thanks.

It's a basic property of the transmission media and can be calculated from the given geometry by elementary electromagnetic equations. You should find the derivation in any profound RF and theoretical electrical engineering text book. On the other hand for a given transmission line type with known impedance, it's nearly a predictable constant value.