Design Investigation of a Broadband Polarization Rotator Using SIW Technology with T-Shaped Slots

 A broadband 90 polarization rotator frequency selective surface (FSS) based on substrate integrated waveguide (SIW) technology is introduced at X band. Bandwidth enhancement is provided by two kinds of perturbation in a square SIW cavity. This is achieved by placing a metallic via at the center of the cavity and slanted via edge at two corners of the cavity. The proposed structure is numerically investigated by CST software. The obtained results show the structure exhibits a relative impedance bandwidth of 12% (8.52-9.61 GHz) with a maximum insertion loss of 0.65 dB. Co-polarized reflection coefficient is less than -10dB over the operating bandwidth.