# skrf.media.mline.MLine.v_g¶

MLine.v_g

Complex group velocity (in m/s)

$j \cdot d \omega / d \gamma$

where: * $$\omega$$ is angular frequency (rad/s), * $$\gamma$$ is complex propagation constant (rad/m)

Notes

the j is used to make propgation real, this is needed because skrf defined the gamma as gamma= alpha +jbeta.

References

https://en.wikipedia.org/wiki/Group_velocity

propgation_constant, v_p