Tools/Coplanar Waveguide Calculator

Coplanar Waveguide Calculator

Calculate CPW and GCPW impedance and characteristics

CPW Parameters

Grounded Coplanar Waveguide (GCPW)

Trace Width - W (mil)

Gap - G (mil)

Substrate Height - H (mil)

Dielectric Constant (εr)

Copper Thickness (mil)

Target Impedance (Ω)

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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