Reflection Coefficient to VSWR Calculator

This tool converts Reflection Coefficient (sometimes referred to as Gamma) Γ to Voltage Standing Wave Ratio or VSWR.



VSWR to Reflection Coefficient Γ


VSWR = (1+|Γ|)/(1-|Γ|)

the absolute value of the reflection coefficient,|Γ| < 1


VSWR is sometimes called standing-wave ratio is a measure of the impedance match between a feedline’s characteristic impedance and the attached load. The load can be an antenna or any RF module such as a filter or amplifier. The greater the degree of mismatch the less efficient the design and implementation.

VSWR is often expressed as a ratio to 1. For example, if the VSWR is 1.9 then it is written as 1.9:1.

Within the context of antennas a good value of VSWR is 1.5 or lower. In an ideal situation the load is perfectly matched to the feedline characteristic impedance and Γ=0. In this case, no signal energy is reflected and all of it is transmitted forward.

If the reflection coefficient is Γ = 1, the denominator in the equation above goes to 0 and VSWR is ∞. This is the worst possible match as all the power is reflected back.