The TE01 mode of a circular metallic waveguide is distinguished by its very low attenuation constant by comparison with the other modes of this guide, and so is a desirable mode to use for low loss transmission. If the operating frequency is chosen so that this mode is above cutoff, then there are other modes of this waveguide which must also be above cutoff.
(a) Construct a set of impressed sources located in this waveguide(either electric or magnetic currents, or a combination of them)that will excite the TE01 mode, but none of the other propagating modes. Draw a picture to illustrate this excitation scheme, and justify your result.