Polarization-Independent, Multilayer Dielectrics at Oblique Incidence

This paper gives solutions for multilayer dielectrics that yield polarization-independent operation at a given angle of incidence and at a given frequency. An exhaustive analysis is given for symmetric three-layer dielectrics surrounded by the same medium. Special solutions are also given for symmetric multilayer dielectrics with more than three layers surrounded by the same medium and for multilayer dielectrics surrounded by different media. Rules are presented for obtaining new polarization-independent solutions by cascading given solutions. Finally, for the purpose of demonstration and comparison of various solutions, different design examples are carried out for polarization-independent 3-dB beam splitters to operate at millimeter wavelengths.