OneSDR contains affiliate links and is a member of the Amazon Services LLC Associates Program, eBay affiliate program, Etsy Affiliate Program. If you make a purchase using one of these links, we may receive compensation at no extra cost to you. This helps support our research, testing and writing.

Reflection Coefficient to VSWR Calculator

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

๐Ÿ” VSWR to Reflection Coefficient ฮ“

Formula

VSWR = (1+|ฮ“|)/(1-|ฮ“|)

the absolute value of the reflection coefficient,|ฮ“| < 1

Background

VSWR is sometimes called standing-wave ratio is a measure of the impedance match between a feedlineโ€™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 ฮ“=0. In this case, no signal energy is reflected and all of it is transmitted forward.

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