Field configurations and propagation constants of modes in hollow rectangular dielectric waveguides

Field configurations and propagation constants of linearly polarized low-loss modes in hollow dielectric rectangular waveguide are computed analytically. The guide comprises an infinitely long prism of rectangular cross section embedded in a medium of complex permittivity. The magnetic permeability of free space is assigned for both media. Separate boundary equations in two dimensions and a perturbation technique applied to the two resulting boundary equations are resorted to. The dimensions of the rectangular guide cross section are assumed large compared to the free-space wavelength, so that the attenuation constant equals the sum of the TE-mode and TM-mode attenuation constants in parallel-plate waveguide.