奈奎斯特频率计算器
使用此奈奎斯特频率计算器快速获得准确的计算结果。
Return Loss
10.88 dB
Return Loss vs VSWR
公式
## 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
计算示例
A cable assembly has VSWR 1.8:1.
- 01Gamma = (1.8 - 1) / (1.8 + 1) = 0.8 / 2.8 = 0.2857
- 02Return loss: -20 x log10(0.2857) = 10.88 dB
- 03Power reflected: 0.2857^2 x 100 = 8.16%
- 04Power delivered: 91.84%
- 05Mismatch loss: -10 x log10(0.9184) = 0.370 dB
常见问题
Is higher return loss better?
Yes. Higher return loss (in dB) means less reflection. A perfect match has infinite return loss.
What is the minimum acceptable return loss?
Typically 10 dB (VSWR 1.92) for most systems. High-performance systems require 15-20 dB or better.
How is return loss measured?
Using a vector network analyzer (VNA) that measures the S11 parameter of the device under test.
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