Square and Rectangular Waveguides with Rounded Corners

Eigenfunctions, eigenvalues, and attenuation constants in waveguides are determined for the square with rounded corners, and for the cigar-shaped rectangle with rounded ends. These cross sections allow, by continuous variation of a parameter, the investigation of the deformation of the modes and attenuation curves of a circular waveguide. Particular attention is given to the H/sub01/ mode and its remarkable attenuation curve.