Define the term w.r.t. waveguide: (i) Cut-OFF frequency (ii) Group Velocity

Define the term w.r.t. waveguide: (i) Cut-OFF frequency (ii) Group Velocity
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1 Answer

Answer :

Group velocity: It is defined as the rate at which the wave propagates through the waveguide and is given by

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The group velocity is also can be defined as the velocity of energy flow in the waveguide system.

Note: When λ=, group velocity becomes zero, whereas phase velocity becomes infinite indicating that there is no propagation of energy along the Waveguide.

Cut off frequency: It is the frequency of the signal above which propagation of waves occur.

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Therefore the lowest frequency which can propagate on the waveguide is fc TE1,0. No energy can propagate in a rectangular waveguide at a frequency below fc TE1,0. This is absolute cut off frequency of the waveguide.

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