Calculadora de Impedância de Linha de Transmissão
Calcule a impedância característica de linhas de transmissão com base nos parâmetros físicos.
Ω
Ω
VSWR
1.50
Reflection Coefficient0.2000
Return Loss14.0 dB
Mismatch Loss0.18 dB
Power Reflected4.0 %
VSWR vs Load Impedance
Formula
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
Exemplo Resolvido
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%
Perguntas Frequentes
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.
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