Stats

  • Locked Locked
  • Replies 9
  • Subscribers 167
  • Views 24775
  • Members are here 0
More Content
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Dielectric Constant of Conductor Copper Layer

wERerABbiT

Hi All,

Setup --> Cross Section

The "Layout Cross Section" window allows "Autosolve Mode" to calculate the trace characteristic impedance given all the parameter values ( thickness, dielectric constant, conductivity etc).

May I know the correct value to put for "Dielectic Constant" of a Conductor Copper layer?

Should this value be infinity? 

Problem is that when I put a very high value, the impedance goes down to almost zero (which isnt true in practice)

Thanks All 

 

 

Parents
  • ScottCad

    Hossein

    I checked a cadence layer stackup against a very high end EM simulator and found that the impedance values in cadence do indeed agree with the EM tool. "Very Close"

    For example here is the stackup I tested with.

    Surface AIR
    TOP Conductor - Copper - thickness 1.2Mil - Conductivity 595900, Dielectric Constant 1, Loss Tangent 0, width 12Mil
    Dielectric, FR4, Thickness 8Mil, Conductivity 0, Dielectric Constant 4.5, Loss Tangent 0.035
    Plane, Copper, Thickness 1.2Mil - Conductivity 595900, Dialectric Constant 1 Loss tangent 0

    This came out to be 54.9 Ohms on the top copper layer for single impedance. Try replicate and see if your results agree too.

    If I understand what you wrote earlier and in the other thread are you saying that if you change the Dielectric Constant of  the top Copper layer that the actual impedance value of the traces on the top layer change too ?.

    Thanks Scott. 

      

     

Reply
  • ScottCad

    Hossein

    I checked a cadence layer stackup against a very high end EM simulator and found that the impedance values in cadence do indeed agree with the EM tool. "Very Close"

    For example here is the stackup I tested with.

    Surface AIR
    TOP Conductor - Copper - thickness 1.2Mil - Conductivity 595900, Dielectric Constant 1, Loss Tangent 0, width 12Mil
    Dielectric, FR4, Thickness 8Mil, Conductivity 0, Dielectric Constant 4.5, Loss Tangent 0.035
    Plane, Copper, Thickness 1.2Mil - Conductivity 595900, Dialectric Constant 1 Loss tangent 0

    This came out to be 54.9 Ohms on the top copper layer for single impedance. Try replicate and see if your results agree too.

    If I understand what you wrote earlier and in the other thread are you saying that if you change the Dielectric Constant of  the top Copper layer that the actual impedance value of the traces on the top layer change too ?.

    Thanks Scott. 

      

     

Children
No Data
Cadence Guidelines

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.