Greetings Pradeep-

What impedance formula are you using? For traveling wave impedance, the common formulas don't have copper area in them. (They do have width and thickness, so you could calculate area, but your context seems to be the copper area on something like a ground plane)

Wayne Thayer

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Pradeep Menon
Sent: Tuesday, May 23, 2017 9:19 PM
To: [log in to unmask]
Subject: [TN] Copper area for impedance calculations

Dear All

Wanted a little more clarity on the copper area that is usually considered for inner layers while calculating impedance. Is it copper area in individual circuit or copper area for each layer after panelisation. There can be instances wherein the two can have quite a good difference which may result in dielectric variation and hence the impedance calculations also.

Can you please suggest what is the commonly followed practice.

Rgds

Pradeep
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