Power transmission in rectangular waveguides
The power transmitted through a waveguide and the power loss in the guide walls can be calculated by means of the complex Poynting theorem .
Power transmission : -
It is assumed that the guide is terminated in such a way that there is no reflection from the receiving end or that the guide is infinitely long compared with the wavelength. From the Poynting theorem ,the power transmitted through a guide is given by :-
For a lossless dielectric, the time-average power flow through a rectangular guide is given by :
For TEmnmodes, the average power transmitted through a rectangular waveguide is given by :
For TMmn modes, the average power transmitted through a rectangular waveguide is given by :
is the intrinsic impedance in an unbounded dielectric.