ABSTRACT
So far, we have discussed plane waves and cylindrical waves. In both of these cases, we could develop with relative ease the solutions based on TM z and TE z modes. We illustrated these solutions by solving some waveguides and cavity problems. The superscript z is added here to indicate that the transverse plane is perpendicular to the z-coordinates. The structures under consideration had a uniform cross section for all values of z. In spherical coordinates, we do not have any such transverse planes, and thus spherical wave problems are mathematically more involved. It is still possible to have mode classification as TM r and TE r .
