Optimizing waveguide cross sections with respect to power handling capability

The problem of optimizing power transmission through uniform perfectly conducting waveguides of double symmetric cross section is discussed. Using an efficiency factor specifically created for single-mode propagation in uniform waveguides, the authors previously developed a unique method of geometric parametrization that determines the waveguide cross-sectional size and shape resulting in maximum power transmission between a source and receiver. Here they use it to analyze the power-handling capabilities of four families of waveguide cross-sectional shapes: rectangular, elliptical, parabolic, and rhombic. Using an efficiency factor based on the two lowest TE modes, it is found that elliptical waveguides can be slightly better than the standard 2:1 rectangular waveguide and that for the four waveguides considered, power-handling is maximized when the second and third TE mode eigenvalues are equal. Good estimates of power-handling capability are obtained by comparison with rectangular shapes or other simple geometries of the same aspect ratio