Based on web pages by Zhi Chang at North Carolina State University.
Modified by Mark Hoffman at Teradyne in May, 2003.

View Calculator
Go back to graphical list of geometries.

Changed (H-T) to (H+H1) to make better.
Log is base e.

For Dr. Howard Johnson's formulas, see his book, High-Speed Digital Design, pages 436-439. Dr. Johnson got the formulas from his references on page 436.
The dielectric constant used in the propogation time was modified by Mark Hoffman to take into account different values for the top and bottom parts.

Asymmetric Stripline Characteristic Impedance and Capacitance Calculator

Input Parameters
Typed In Used in Calcs
Force symmetric if S=1:
Dielectric Constant (top):
Dielectric Constant (bottom):
Line Thickness (T) in mils:
Line Width (W) in mils:
Substrate Height (Ht) (top) in mils:
Substrate Height (Hb) (bottom) in mils:
Output Results
Zhi Chang Dr. Johnson
Impedance in Ohms:
Capacitance in pf/inch:
Inductance in nh/inch:
Time in pS/inch:
Resistance in mOhm/inch:

Go back to graphical list of geometries.

  1. Input parameters (Push calculate to fill in defaults)
  2. Push the CALCULATE button
  3. Then Rock'n'Roll
  4. If necessary, push the CLEAR button