K-Band Linear to Circular Polarization Converter with Broadband Transmission and High Angle Stability

This paper presents a novel K-band linear to circular polarization converter (K-LCPC) based on metasurfaces, which exhibits broadband transmission and high angle stability characteristics. The unit cell of our designed metasurface is a sandwich-shaped structure comprising two same dielectric substrates and three metallic layers that are not completely identical. Both of the front and back metal layers are identical, with each layer containing two elongated metal strips positioned along the two diagonal lines, while the middle metal layer is a square ring. The simulated results indicate that the axial ratio (AR) bandwidth for transmittance over -2 dB is 25%, ranging from 20.3 to 26.1 GHz. Moreover, the insertion loss is below 2 dB within this frequency band, and its oblique incidence stability can reach up to
$60^{\circ}$
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