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VSWR, return loss & reflection coefficient

Convert between VSWR, return loss (dB), reflection coefficient (Γ), and reflected/transmitted power.

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VSWR, return loss & reflection coefficient

Enter any one value — the others are calculated automatically.

VSWR —
Return loss —
Reflection coefficient (Γ) —
Reflected power —
Transmitted power —
Mismatch loss —

Formulas used

  • VSWR = (1 + Γ) ÷ (1 - Γ)
  • Γ = (VSWR - 1) ÷ (VSWR + 1)
  • Return loss (dB) = -20 × log₁₀(Γ)
  • Reflected power (%) = Γ² × 100
  • Transmitted power (%) = (1 - Γ²) × 100
  • Mismatch loss (dB) = -10 × log₁₀(1 - Γ²)

Frequently asked questions

How are VSWR and return loss related?

Return loss in dB = −20 × log₁₀(|Γ|), where the reflection coefficient |Γ| = (VSWR − 1) / (VSWR + 1). A VSWR of 1.5:1 is about 14 dB of return loss.

What VSWR is considered good?

It depends on the application, but a VSWR of 1.5:1 (≈14 dB return loss) or better is typical for many RF systems, and 1.2:1 (≈21 dB) is excellent.

What does a reflection coefficient of 0 mean?

Zero reflection (Γ = 0, VSWR = 1:1) means the load is perfectly matched to the line and all incident power is delivered to the load.