Maximum microstrip current

how can i calculate the maximum DC current for a microstrip with metal(gold) cross section S? WHere i can find documentation or formulas?

regards

look for MWI.EXE into www.rogerscorporation.com

It's an old fashioned MSDOS program but for my opinion still the most exaustive microstip calculator.

It include electric current and thermal considerations both on copper and dielectric.

Also some reference article are reported.

http://www.rjungert.com/copper.htm

Perhaps you can try this:
http://www.geocities.com/CapeCanaver...TraceWidth.htm

I need calculator or formulas for allumina substrate and gold metallization. These software are for PCB or copper metallization.

regards

The basics concept are the same, Flex PCB or Alumina.
More specifically, Au conductivity, σAu is 0.78σCu
Thermal conductivity of AlO3 is so larger than glass/PTFE that alumina is considered as a "good" thermal conductor, so heat generated may be well dissipated, so alumina μstrip lines tolerates more, more power than PTFE/Glass lines (same W dimension).

A question for you. Are U sure your conductor metal is Au ? Usuallly, over Alumina, the thick film is a sandwich where Au is the top metal so not involved with RF propagation.