Dual-band/broadband Circular Polarizers Designed with Cascaded Dielectric Septum Loadings

Abstract

A simple method is presented in this paper for realizing a dielectric septum-loaded type circular polarizer with either dual-band or a single broadband response. Two dielectric septum sections with different dielectric constants and lengths that introduce various phase delay to the x- and y-polarizations of the electric field in the same frequency range are cascaded orthogonally to obtain a dual-band response. A single wideband response can also be achieved if two dielectric septum sections are cascaded in parallel instead. Simulations in Ansoft HFSS show that flatter phase response and wider bandwidth can be obtained by the proposed polarizer comparing to single section ones. Moreover, a dual-band response can only be achieved with a two-section design. Taking advantage of dielectric septum-loaded type circular polarizers, the fabrication error or inaccurate dielectric constants can easily be compensated by adjusting the lengths of dielectric septum sections.