Return Loss Rechner — Formel

Understanding Return Loss

Return loss measures how much signal is reflected due to impedance mismatch, expressed in positive decibels (higher is better).

Formulas

Gamma = (VSWR - 1) / (VSWR + 1)

Return Loss = -20 x log10(Gamma) dB

Mismatch Loss = -10 x log10(1 - Gamma^2) dB

Quick Reference

  • 20 dB return loss: 1% power reflected, VSWR 1.22
  • 14 dB return loss: 4% power reflected, VSWR 1.50
  • 10 dB return loss: 10% power reflected, VSWR 1.92

    • Lösungsbeispiel

    A cable assembly has VSWR 1.8:1.

    1. Gamma = (1.8 - 1) / (1.8 + 1) = 0.8 / 2.8 = 0.2857
    2. Return loss: -20 x log10(0.2857) = 10.88 dB
    3. Power reflected: 0.2857^2 x 100 = 8.16%
    4. Power delivered: 91.84%
    5. Mismatch loss: -10 x log10(0.9184) = 0.370 dB