A compact dual-band linear-to-circular polarization converter for X-band and Ku-band applications

This paper introduces a compact reflective dual-band linear-to-circular polarization converter (D-LCPC). The converter unit cell consists of a modified L-shaped patch and three parallel dipoles to enable dual-band operation. It demonstrates a 3-dB axial ratio bandwidth (ARBW) ranging from 8.09 to 10.59 GHz (26.76%) for the lower band and 17.53 to 18.63 GHz (6.08%) for the upper band, specifically for y-polarized incidence. The design enables the conversion from linear polarization to right-hand circular polarization in the dual- band. Furthermore, the axial ratio remains below 1.20 dB within the frequencies of 8.27 to 10.01 GHz and 17.62 to 18.47 GHz, indicating a high efficiency of circular polarization conversion on an average of 99.5%. This innovative structure is suitable for creating circularly polarized systems for X-band and Ku-band satellite communication, especially in weather RADAR communications.