Multi-octave linear-to-circular polarizers

Linear-to-circular polarizers operating at mm-wave frequencies with multiple octaves of bandwidth are reported. First, a polarizer constructed from cascaded anisotropic dielectrics is discussed. This polarizer scales the design of achromatic waveplates from optical frequencies down to mm-wave frequencies. In addition, the polarizer is constructed from artificial dielectrics (metamaterials) rather than naturally occurring crystals, which would be too bulky at these lower frequencies. Next, a broadband polarizer utilizing a meanderline/metamaterial combination is reported. The polarizer significantly extends the bandwidth over previous microwave designs by optimizing the orientation of each metallic layer, as well as combining meanderline and metallic patch geometries into the design. Both polarizers operate at incident angles up to 60° from normal.