Three-dimensional analysis of a cylindrical waveguide converter for circular polarization by the spatial network method

Two types of converters for generating a circularly polarized wave from a linearly polarized one are analyzed using the spatial network method (SNM). The converter types studied are: those loaded with metal plates in a cylindrical waveguide and those loaded with a fin. The cutoff wavelengths are computed from the frequency response by applying the fast Fourier transform. The phase-shift constants and guide wavelengths are computed from the spatial and time variations of the electric field distribution. The whole distribution of fields obtained by the SNM is shown to provide detailed information on the field properties, such as the local field concentration. In particular, the process of generating either a circularly or elliptically polarized wave from a linearly polarized wave is shown by three-dimensional and time-domain analysis. It is confirmed that the fundamental characteristics of the converters agree well with the analysis and measured results