Tools/Coplanar Waveguide Calculator

Coplanar Waveguide Calculator

Calculate CPW and GCPW impedance and characteristics

CPW Parameters

WGGHSubstrate (εr)Ground Plane

Grounded Coplanar Waveguide (GCPW)

Calculated Results

Characteristic Impedance

78.45 Ω

Adjust decrease gap or increase width

Effective εr

2.716

Delay

139.62

ps/inch

Velocity

181.9

mm/ns

Gap for 50Ω

100.00 mil

k₀ factor

0.5000

k₁ factor

0.3775

CPW vs GCPW Comparison

CPW (No Ground Plane)

  • • Lower loss at high frequencies
  • • Less ground current
  • • Harder to control impedance
  • • More sensitive to nearby structures
  • • Best for: RF/microwave, test fixtures

GCPW (With Ground Plane)

  • • Better field containment
  • • Easier impedance control
  • • Lower crosstalk
  • • Better for dense layouts
  • • Best for: High-speed digital, mixed-signal
For GCPW, ensure coplanar ground is stitched to the reference plane with vias every λ/10 to prevent parallel plate modes and maintain good performance at high frequencies.

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