VSWR (Standing Wave Ratio)
Calculate the voltage standing wave ratio (VSWR), VSWR = (1 + |Γ|) ÷ (1 − |Γ|), from the magnitude of the reflection coefficient |Γ|. The result (dimensionless, expressed as X:1) measures how well an antenna or load is matched to the transmission line: VSWR = 1:1 is a perfect match (all power delivered); higher values mean part of the wave is reflected back, forming standing waves that reduce efficiency and may damage the transmitter. Typically VSWR up to 1.5:1 or 2:1 is acceptable. Enter the magnitude of the reflection coefficient.
Resultado
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VSWR (relação de onda estacionária)
Quando a impedância de uma antena (ou carga) não é igual à da linha de transmissão que a alimenta, parte da onda enviada é refletida de volta. A onda incidente e a refletida se somam ao longo do cabo formando uma onda estacionária, com máximos e mínimos de tensão fixos no espaço. A relação de onda estacionária de tensão (VSWR, ou ROE em português) mede a severidade disso: VSWR = (1 + |Γ|) ÷ (1 − |Γ|), onde |Γ| é o módulo do coeficiente de reflexão. A interpretação é direta: VSWR = 1:1 significa casamento perfeito — nenhuma reflexão, toda a potência é entregue à antena. Quanto mais alto o VSWR, mais potência volta para o transmissor: VSWR 2:1 reflete cerca de 11% da potência, e valores muito altos podem superaquecer e danificar o estágio final do transmissor (por isso muitos têm proteção que reduz a potência com VSWR alto). Na prática aceita-se VSWR até 1,5:1 em sistemas exigentes ou 2:1 em aplicações comuns. O VSWR é a medida de rotina para verificar a sintonia de antenas e o casamento de cabos. Informe o módulo do coeficiente de reflexão.
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Reflection Coefficient
Calculate the reflection coefficient, Γ = (Z_L − Z₀) ÷ (Z_L + Z₀), from the load impedance Z_L and the line's characteristic impedance Z₀ (ohms). The result (dimensionless, between −1 and 1) gives the fraction of the incident wave reflected by the impedance discontinuity: Γ = 0 means a perfect match (no reflection); Γ = ±1 is total reflection (open or short circuit). It is the basis of impedance matching in transmission lines and relates directly to VSWR and return loss. Enter the load impedance and the characteristic impedance.
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