An only metal, compact, and circular polarizer designed with helical array rods

Abstract

This paper presents a simple method to realize a circular polarizer by inserting rods arranged helically in a cylindrical waveguide. In the proposed polarizer, the rods are installed to excite the electric fields perpendicular to the input field. In addition, the rod locations create a 90 • phase difference between two perpendicular axes to convert the polarization from linear to circular. In the proposed structure, the axial ratio is smaller than 0.4 dB, and the phase difference is approximately 90 • at a frequency of 10 GHz. In addition, the reflection coefficients are better than −14 dB for both the E x and E y polarizations at the same frequency. Additionally, this structure is very compact compared to similar systems. Furthermore, this is made only of metal. Therefore, there is no dielectric loss. The validation results are in good agreement with the simulation.