Propagation properties of some non-homogeneous guiding structures used in polarization transformers

Summary form only given. Changing the polarization of a wave is a common procedure in many applications in the field of communication, measurement systems etc. Polarization transformers are passive and linear devices, based on the differential phase-shift generated between two orthogonal propagation modes. In this paper, a simple method for the numerical analysis of a variety of non-homogeneous waveguides is presented. Essentially, the proposed procedure is based on the application of a finite-difference method in the frequency domain (FD-FD). Versatile programs can be created using the MATLAB programming language, for use with different waveguide geometries. These programs are relatively simple and do not demand large computational efforts, so that they can represent an economic solution for the analysis of non-homogeneous propagating structures. In the paper are presented some results obtained by applying methods of this type to the analysis of a number of inhomogeneous guiding structures, in the form of dispersion characteristics, β=β(ω), and of differential phase shift per unit length characteristics versus frequency. This last form allows the determination of the working frequency band, for each type of differential phase-shift structure. As a conclusion, some new structures of differential phase-shifters with improved characteristics are presented