Voltage Standing Wave Ratio Calculator

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In electrical and electronics systems, the Voltage Standing Wave Ratio (VSWR) is a statistic used to assess the level of impedance mismatch over transmission lines.
It measures how much signal reflection is brought on by impedance mismatches by dividing the maximum voltage along a transmission line by the minimum voltage.

VSWR is primarily used in electrical and electronics circuits to evaluate the impedance matching and signal transmission quality between linked components.
It assists in locating possible problems including power inefficiency, signal loss, and electromagnetic interference brought on by reflections in transmission lines.

Understanding Voltage Standing Wave Ratio :

Effects of VSWR on Performance:

A high VSWR can have several negative effects on the performance of a transmission system:

Transmitter Power Amplifiers Can Be Damaged: The elevated voltage and current levels caused by standing waves along the feeder pose a risk to the output transistors of the transmitter.

PA Protection Reduces Output Power: To reduce the chance of excessive SWR levels causing harm to the power amplifier, numerous transmitters incorporate safeguard mechanisms. These circuits function to lower the output of the transmitter in response to an increase in SWR.

High Voltage and Current Levels Can Damage Feeder: Feeders typically function within their designated safety thresholds. However, instances of peak currents can induce localized overheating, potentially resulting in the degradation or melting of plastic components. Elevated voltage levels may also trigger arcing in specific situations.

Delays Caused by Reflections Can Cause Distortion: Reflected signals originating from impedance mismatch travel back to the source, potentially bouncing back towards the antenna, causing a delay equivalent to twice the signal’s transmission duration along the feeder. This phenomenon can result in inter-symbol interference in data transmission and may produce ghost images in analog TV transmission.

What is Standing Wave Ratio (SWR)?

The standing wave ratio (SWR) represents the relationship between the highest and lowest amplitudes of a standing wave. Discover further insights into SWR, including its definition, operational principles, and various practical uses.

VSWR in Antenna Systems:

The Voltage Standing Wave Ratio (VSWR) serves as a measure of the disparity between an antenna and the connecting feed line. It is often referred to as the Standing Wave Ratio (SWR). VSWR values range from 1 to infinity, with a VSWR below 2 generally deemed adequate for the majority of antenna uses.


  • Antenna Systems
  • RF and Microwave Systems
  • Telecommunications
  • Test and Measurement Equipment
  • Radio and Broadcasting

Use this online calculator to determine the Voltage Standing-Wave Ratio (VSWR). A transmission line’s mismatch with its load is measured by VSWR, which shows how non-uniform an electromagnetic field is. To find the Reflection Coefficient, Reflected Power, Return Loss, and Mismatch Loss, enter the VSWR number. This tool offers information on the transmission line’s efficiency and signal loss.

Note : Don’t end with comma ( , )

Voltage Standing Wave Ratio (v)


\[ |Γ| = \frac{v-1}{v+1} \]
\[p = 100⋅Γ^2\]
\[l=10⋅log(1−Γ^2 )\]


  • v = Voltage Standing Wave Ratio
  • Γ = Reflection Coefficient
  • p = Reflected Power
  • d = Reflected Power(dB)
  • l = Mismatch Loss

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