standing wave ratio (SWR)

The ratio of the amplitude of a standing wave at an anti-node (minimum) to the amplitude at an adjacent node (maximum). Note 1: The standing wave ratio (SWR) in a uniform transmission line is given by where is the reflection coefficient. Note 2: Reflections occur as a result of discontinuities, such as an imperfection in an otherwise uniform transmission line, or when a transmission line is terminated with other than its characteristic impedance.