VSWR / Return Loss Calculator
Reflection coefficient, return loss and mismatch loss from VSWR.
Input
ℹ VSWR ≥ 1. 1:1 = perfect match; higher = more reflected power.
Results
Reflection Coeff (Γ)—
Return Loss—
Mismatch Loss—
Power Reflected—
💡 Usage & Formula
Γ = (VSWR−1)/(VSWR+1); RL = −20·log₁₀|Γ| dB; ML = −10·log₁₀(1−Γ²) dB; reflected power = Γ².
When you need it: Quantifying an impedance mismatch on an RF line — converting between VSWR, return loss, reflection coefficient and the fraction of power bounced back.
Worked example: Γ = 0.2 → VSWR = (1 + 0.2)/(1 − 0.2) = 1.5 and return loss = −20·log₁₀(0.2) = 14 dB. A 2:1 VSWR (~9.5 dB RL) reflects about 11% of the incident power.
Tips & gotchas:
- Lower VSWR means a better match — 1:1 is ideal; higher numbers mean more reflection.
- Mismatch (transmission) loss is small even at VSWR 2 (~0.5 dB); reflections matter more for amplifier stability and hot spots.
- Return loss is quoted as a positive dB figure — how far the reflected wave sits below the incident.
- Match is frequency-dependent; measure at the band of interest, not just at one spot frequency.
📖 References:SWR (Wikipedia)