Voltage Standing Wave Ratio

Adjust the complex reflection coefficient and watch sixteen faded snapshots of the instantaneous real voltage along a transmission line. Peaks and nulls are set by the magnitude of Γ, while the phase of Γ slides the pattern along the line.

Back to portal

Re[V(z,t)] = Re{(e^-j2πz/λ + Γe^j2πz/λ)e^jωt}
envelope = ±|e^-j2πz/λ + Γe^j2πz/λ|
VSWR = (1 + |Γ|) / (1 - |Γ|)

1.00 VSWR

0.00 |Γ|

1.00 Vmax / Vinc

1.00 Vmin / Vinc

Reflection coefficient

Drag the blue marker or use the sliders. Magnitude controls the VSWR; phase shifts the standing-wave pattern along the line.

Magnitude, |Γ| 0.47

Phase, angle(Γ) 32 deg

Γ plane drag marker

0.40 Re(Γ)

0.25 Im(Γ)

Load impedance needed

Line impedance Z0 Ω

Z_L = Z₀(1 + Γ) / (1 - Γ)

1.00 + j0.00 normalized Z_L / Z₀

50.00 + j0.00 Ω load impedance Z_L

A larger |Γ| makes deeper nulls and higher peaks in the envelope. Changing the angle keeps the VSWR the same but moves the standing-wave pattern along z.

Instantaneous real voltage over 3 wavelengths