Is higher return loss better?

Yes. Higher return loss (in dB) means less reflection. A perfect match has infinite return loss.

What is the minimum acceptable return loss?

Typically 10 dB (VSWR 1.92) for most systems. High-performance systems require 15-20 dB or better.

How is return loss measured?

Using a vector network analyzer (VNA) that measures the S11 parameter of the device under test.

Return Loss Calculator

Calculate return loss in dB from VSWR or reflection coefficient, and convert between mismatch metrics.

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VSWR

Return Loss

10.88 dB

Reflection Coefficient0.2857

Power Reflected8.16 %

Power Delivered91.84 %

Mismatch Loss0.370 dB

Return Loss vs VSWR

View formula & how it works →

Understanding Return Loss

Return loss measures how much signal is reflected due to impedance mismatch, expressed in positive decibels (higher is better).

Formulas

Gamma = (VSWR - 1) / (VSWR + 1)

Return Loss = -20 x log10(Gamma) dB

Mismatch Loss = -10 x log10(1 - Gamma^2) dB

Quick Reference

20 dB return loss: 1% power reflected, VSWR 1.22

14 dB return loss: 4% power reflected, VSWR 1.50

10 dB return loss: 10% power reflected, VSWR 1.92

Example Calculation

A cable assembly has VSWR 1.8:1.

01Gamma = (1.8 - 1) / (1.8 + 1) = 0.8 / 2.8 = 0.2857
02Return loss: -20 x log10(0.2857) = 10.88 dB
03Power reflected: 0.2857^2 x 100 = 8.16%
04Power delivered: 91.84%
05Mismatch loss: -10 x log10(0.9184) = 0.370 dB

Frequently Asked Questions

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