A novel type of waveguide polarizer with large cross-polar bandwidth

A wideband quarter-wave polarizer is presented having a rectangular cross-section, where all four walls are loaded with a dielectric or artificial dielectric. A much larger bandwidth compared to existing polarizers can be obtained without increasing the insertion loss. A polarizer so constructed was fabricated and measured. The polarizer had a differential phase shift within 90 degrees +or-0.7 degrees corresponding to 44 dB isolation, insertion loss below 0.06 dB, and return loss below -24 dB (VSWR>