Improved polarization converter using symmetrical semi-ring slots

A symmetrical semi-ring polarization converter based on slotted frequency selective surface (SFSS) is presented in this paper. The proposed SFSS is a free metallic screen without supported media, and the corresponding formulas are provided to calculate its frequency response. Good agreements can be observed between the simulated and calculated results. The phase difference between TE and TM components can maintain at 90° over a wide frequency band. The insertion loss is -3.07dB and the 3dB axial ratio bandwidth is about 15% of the center frequency.