传输线阻抗计算器
使用此传输线阻抗计算器快速获得准确的计算结果。
VSWR
1.50
VSWR vs Load Impedance
公式
## What is VSWR? VSWR (Voltage Standing Wave Ratio) measures impedance mismatch between a transmission line and its load. A perfect match is 1:1. ### Formulas **Gamma = |Z_load - Z_0| / |Z_load + Z_0|** **VSWR = (1 + Gamma) / (1 - Gamma)** **Return Loss = -20 x log10(Gamma) dB** ### Interpretation - VSWR 1.0: Perfect match (0% reflected) - VSWR 1.5: Good match (4% reflected) - VSWR 2.0: Acceptable (11% reflected) - VSWR 3.0+: Poor match (25%+ reflected)
计算示例
75 ohm load on a 50 ohm transmission line.
- 01Gamma = |75 - 50| / |75 + 50| = 25 / 125 = 0.2000
- 02VSWR = (1 + 0.2) / (1 - 0.2) = 1.2 / 0.8 = 1.50
- 03Return loss: -20 x log10(0.2) = 13.98 dB
- 04Power reflected: 0.04 = 4.0%
常见问题
What VSWR is acceptable for most applications?
Below 2:1 is acceptable for most systems. Below 1.5:1 is good. Antenna systems often specify 1.3:1 or better.
Can VSWR damage equipment?
High VSWR reflects power back to the transmitter, causing heating. Most transmitters reduce power automatically above VSWR 3:1.
What is the relationship between VSWR and return loss?
They are different ways to express the same mismatch. Return loss = 20 x log10((VSWR+1)/(VSWR-1)) dB.
学习