Grounded Coplanar Waveguide (G-CPW)
or Conductor-Backed Coplanar Waveguide (CB-CPW)

2010.10.30 Takuichi Hirano

Input

Dielectric constant
A half width of signal line a mm
Distance from the center to the slot edge of the ground b mm
Thickness of conductor t mm
Thickness of substrate h mm

Output

Characteristic impedance Z0 Ohms
Effective relative permittivity

 

([2] or Eq.(3.10) in [3])

([2] or Eq.(3.10) in [3])

(Eq.(8) in [1])

(Eq.(9b) in [1])

where, K(m) is the complete elliptic integral of the first kind.

(Eq.(9a) in [1])

(Eq.(10) in [1])

References
  1. G. Ghione, C.U. Naldi, "Coplanar Waveguides for MMIC Applications: Effect of Upper Shielding, Conductor Backing, Finite-Extent Ground Planes, and Line-to-Line Coupling," IEEE Transactions on Microwave Theory and Techniques, Vol.35, No.3, pp.260-267, March 1987.
  2. Y.-C. Shih, "Broadband characterization of conductor-backed coplanar waveguide using accurate on-wafer measurement techniques" Microwave J., Vol.34, No.4, pp.95-105, April 1991.
  3. R.N. Simons: Coplanar Waveguide Circuits, Components, and Systems, Wiley-IEEE Press, 2001.
Appendix

Download Mathematica Notebook File: cbcpw.nb (43KB)

Copyright(c) 2010 Takuichi Hirano

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