VSWR calculator from direct and reflected powers

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This calculator determines the voltage standing wave ratio (VSWR) from the forward (Pf) and reflected (Pr) powers. It helps evaluate the quality of impedance matching between a source and a load in RF systems, ensuring efficient signal transmission.

Formula

VSWR = (1 + √(Pr / Pf)) / (1 − √(Pr / Pf))

Explanation of the formula

The VSWR is calculated from the ratio between the reflected power and the transmitted power. A VSWR value close to 1 indicates almost perfect matching, while a high value reveals losses due to reflections. The calculation uses the square root of the Pr/Pf ratio to derive the ratio of incident and reflected voltages.

Uses of the calculator

  • Evaluate the effectiveness of impedance matching of an antenna or transmission line.
  • Diagnose power losses due to reflections.
  • Optimize the performance of RF transmitters and receivers.
  • Practical tool for engineers, RF technicians and electronics students.

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