The energy flow inside a waveguide cavity using the SBR and GRE methods

The authors quantitatively and qualitatively compare the representation of the fields in the interior of an open-ended waveguide cavity with an electromagnetic plane wave excitation using the SBR (shooting and bouncing rays) and GRE (generalized ray expansion) methods. The basic difference in the SBR and GRE methods is in the way the rays are initially launched into the cavity. In the SBR method, and incident electromagnetic plane wave is modeled by a set of parallel GO (geometrical optics) rays that are launched into the cavity interior. In the GRE method, the incident field in the cavity aperture is replaced by equivalent surface currents which radiate the desired fields into the cavity interior. For parallel-plate waveguide cavities with apertures of 20 lambda and lengths up to 100 lambda , the SBR, GRE, and modal-based backscattering results all agree very well.<>