1. Coupling to the TEmn modes in waveguide

As briefly enounced in introduction, the EM power carried in a waveguide is configured under $T{E}_{mn}$ and $T{M}_{mn}$ modes. The so-called transverse electric modes, shortened with the abbreviation $TE$ , are characterized by the combination of three field vectors. Two orthogonal vectors involving electric and magnetic fields, are contained in the cross section of the waveguide, while an additional magnetic vector is established along its length.