LAUSR

In this letter, an ultra‐thin and broadband transmissive linear‐to‐circular polarization converter (LTCPC) is presented. This LTCPC consists of a single substrate with symmetrical metallic patterns on its surface, composed of split rings and an internally orthogonal crossed dipole. By orthogonal decomposition of linear polarized (LP) waves from different directions, this converter can realize circularly polarized (CP) transmission, and the type of CP transmitted wave can be switched by changing the incident LP direction. The proposed converter achieves a 3 dB axial ratio (AR) bandwidth of 32% (26.5–36.6 GHz) and maintains stable AR performance under oblique incidence angles up to 4 0 ∘ $4{0}^{\circ }$ . It features a low profile with a compact volume of 0.016 λ 0 3 ${\lambda }_{0}^{3}$ , where λ 0 ${\lambda }_{0}$ is the wavelength of the center frequency. After full wave simulation, a prototype of 16 × 16 $16\times 16$ cells was fabricated and tested. A comparison shows that the tested and simulated results are almost the same. With its good polarization conversion performance and ultra‐thin profile, the proposed LTCPC can find wide applications in Ka‐band satellite communications.