VSWR conversion calculator for RF systems

VSWR Calculator Formula

The VSWR Calculator determines key parameters of a transmission line based on the input VSWR (Voltage Standing Wave Ratio). The main formulas used are:

Reflection Coefficient (Γ) = (VSWR – 1) / (VSWR + 1)

Return Loss (RL) = -20 × log10(Γ)

Mismatch Loss (ML) = -10 × log10(1 – Γ²)

Formula Explanation

The VSWR value indicates how well a load is matched to a transmission line. A perfect match has VSWR = 1, which corresponds to zero reflection (Γ = 0), infinite return loss, and no mismatch loss. Reflection Coefficient Γ measures the portion of the signal reflected back due to impedance mismatch. Return Loss RL quantifies the signal loss caused by reflection in decibels, while Mismatch Loss ML represents the power loss due to VSWR mismatch.

Uses of VSWR Calculator

  • Check transmission line performance in RF and microwave circuits.
  • Evaluate antenna matching for optimal signal transfer.
  • Measure reflection and return loss in network design.
  • Determine mismatch losses for high-frequency signal lines.
  • Support troubleshooting of VSWR issues in communication systems.

Formula Example

Suppose the measured VSWR of a line is 2.5:

Γ = (2.5 – 1) / (2.5 + 1) ≈ 0.429

RL = -20 × log10(0.429) ≈ 7.35 dB

ML = -10 × log10(1 – 0.429²) ≈ 0.87 dB

This example shows that a VSWR of 2.5 leads to a moderate reflection and some power loss along the line.