Mismatch Loss Calculator

This tool computes the mismatch loss from Voltage Standing Wave Ratio (VSWR).

Formula

Γ = (VSWR – 1)/(VSWR + 1)

Return Loss (dB) = -20*Log₁₀(|Γ|)

Mismatch Loss (dB) = -10*Log₁₀(1 – |Γ|²)

Reflected Power (%) = 100*(|Γ|²)

Transmitted Power (%) = 100*(1 – |Γ|²)

Example Calculation

For a VSWR of 2, the mismatch loss is calculated to be 0.51. 89% of the power is transmitted forward, while 11% is reflected back into the source. As the VSWR increases, the quality of the match deteriorates and more power is reflected back. For a VSWR of around 5.9, half the power is reflected back.

A good value of VSWR is 1.5, where 96% of the power is transmitted forward and only 4% is reflected back. The ideal value of VSWR is 1 where none of the power is reflected back.