The speed of a signal within a rectangular waveguide is given by the group velocity of the associated mode (Equation ???). The group velocity for this mode at the frequency of interest is ...The speed of a signal within a rectangular waveguide is given by the group velocity of the associated mode (Equation ???). The group velocity for this mode at the frequency of interest is given by Equation ???. Using this equation, the speed of propagation is found to be ≅2.26×108m/s, which is about 75.5% of c.