Transmission Line Standing Wave Ratio (SWR) Formula & Calculator



Load to Characteristic Impedance Ratio Calculation

p - Reflection coefficient
Print

standing wave ratio (SWR) calculator - step by step calculation, formula & solved example problem to find the ratio of load impedance matching to the transmission line or wave guide characteristic impedance (Z0). Zterm - load or terminal impedance & Z0 - characteristic impedance are the key terms of this calculation. Higher & lower SWR ratio values indicate that the higher & lower standing wave along the transmission line.

Formula

The below mathematical formula is used in this calculator to find the standing wave ratio (SWR) of the transmission line
formula to calculate SWR - standing wave ratio of transmission line

Solved Example

The below step by step solved example problem may helpful for users to understand how the input values are being used in such calculations to find the ratio of load impedance matching to the transmission line or wave guide characteristic impedance (Z0).
Example Problem
Find the SWR of the transmission line or wave guide whose load or terminal impedance Zterm = 7.5 kilo ohms & characteristic impedance Z0 = 6 kilo ohms.
Solution
The given data
terminal impedance Zterm = 7.5 kilo Ω
characteristic impedance Z0 = 6 kilo Ω

Step by step calculation
Formula to find ρ = (Zterm - Z0)/(Zterm + Z0)
substitute the values in the above formula
= (7500 - 6000)/(7500 + 6000)
ρ = 0.11

Step by step calculation
Formula to find SWR = (1 + |ρ|)/(1 - |ρ|)
substitute the values in the above formula
= (1 + 0.11)/(1 - 0.11)
SWR = 1.24

In the field of electrical engineering, it's important to calculate the standing wave ratio of the medium to analyse the transmission lines characteristics. The above formula, step by step calculation & solved example problem may be useful for users to understand how the values are being used in the formula to find ratio of load impedance (Zterm) matching to the transmission line or wave guide characteristic impedance (Z0), however, when it comes to online for quick calculations, this calculator helps the user to perform & verify such calculations as quick as possible.