VSWR to Reflection Coefficient Calculator

What is Reflection Coefficient?

In electrical engineering, the reflection coefficient is a parameter that defines how much of the electromagnetic wave is reflected due to the impedance discontinuity in a transmission path. The reflection coefficient is the ratio of the amplitude of the reflected wave to the amplitude of the incident wave, with each expressed as phasors, and the symbol of this coefficient is Γ (capital gamma). 

How to relate the VSWR and reflection coefficient?

VSWR (Voltage Standing Wave Ratio) measures the efficiency of power transferred from a source to a load via a transmission line/cable. If the impedance mismatch between the transmission line/cable to the load is high that leads to a standing wave pattern along the transmission line. VSWR means that the ratio of the maximum voltage to the minimum voltage in the standing wave pattern along the transmission line. 

For an ideal system, there is no impedance mismatch between the transmission line & load, hence no reflection, so no standing wave. Thus, for this system, VSWR = 1:1 (i.e.,100 %   power transferred from a source to a load via a transmission line/cable). As we know that the reflection coefficient defines the amount of the electromagnetic wave is reflected due to the impedance discontinuity in a transmission path. 

But, for a practical system, there will be a small impedance mismatch always; hence, VSWR is like 3.0:1, 2.0:1. Higher VSWR implies a higher mismatch and higher reflection coefficient (i.e., high EM wave reflection in a transmission circuit).      

The following formula relates the VSWR and reflection coefficient. This formula is used to calculate the reflection coefficient from the given VSWR.

Where,

Γ = Reflection coefficient 

VSWR = Voltage standing wave ratio