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RF Mismatch Calculator – Return Loss, VSWR & Reflection Coefficient
Convert between return loss, VSWR, and reflection coefficient, then estimate reflected power, accepted power, and mismatch loss. Useful for antennas, RF cables, filters, amplifiers, and impedance matching checks.
Input Parameters
Results
Equations Used
Return Loss: RL = -20 log10(|Γ|)
VSWR: VSWR = (1 + |Γ|) / (1 - |Γ|)
Reflected Power Fraction: Pref/Pfwd = |Γ|²
Mismatch Loss: ML = -10 log10(1 - |Γ|²)
Frequently Asked Questions (FAQ)
Q1: What is return loss?
Return loss is the ratio between forward power and reflected power, expressed in dB. Higher return loss usually means a better match.
Q2: What is a good VSWR?
VSWR near 1:1 is ideal. In many RF systems, VSWR below 1.5:1 is good and below 2:1 is often acceptable depending on power and application.
Q3: How are VSWR and reflection coefficient related?
Both describe impedance mismatch. Reflection coefficient is the reflected voltage ratio; VSWR is the standing-wave ratio derived from it.
Q4: Does mismatch loss include cable loss?
No. Mismatch loss only estimates power not delivered due to reflection at an interface. Cable attenuation must be added separately.
Q5: Can I use this for antennas?
Yes. It is commonly used for antenna match evaluation, but antenna performance also depends on radiation efficiency, ground plane, installation, and bandwidth.
