Broadband Single Layer Transmission Type Linear to Circular Polarization Converter with Higher Conversion Efficiency

This paper presents a broadband transmission type linear to circular polarization converter (LCPC) with the advantages of a single metal layer, high conversion efficiency, and low insertion loss (IL). The proposed unit cell consists of narrow and wide metal strips which are oriented along the two diagonals. The strips exhibit high pass filtering characteristics with low cutoff frequency and higher resonance outside the operational band. The two orthogonal transmitted components from the metasurface have approximately equal magnitudes with a phase difference of 90° and the resultant wave is right-hand circular polarized (RCP). The proposed converter shows a 3 dB axial ratio bandwidth (ARBW) of 48.2 % between 19.22-31.42 GHz. The unit cell has a periodicity of 2.4 mm or 0.2 λ
0
, where λ
0
is the wavelength at the center frequency of the operational bandwidth (BW). The proposed structure shows incidence angle stability up to 35° in two principal planes.