Broadband Linear-to-Circular Polarizing Reflector for Space Applications in Ka-Band

This article presents a novel low-profile broadband polarizing reflector to convert dual linear polarization (LP) into dual circular polarization (CP). The polarizing cell is based on printed dipole technology and presents a wideband performance in Ka-band. The dimensions of the printed dipoles are adjusted cell by cell to improve the reflection phase performance against variations in the incidence angles or in the cell dimensions. A 25 cm flat polarizing reflector demonstrator has been designed, fabricated, and tested. The design has been optimized for transmit (19.2-20.2 GHz) and receive (29-30 GHz) frequencies in Ka-band, but the broadband behavior of the cell provides satisfactory results also at the intermediate frequencies. The measured patterns show a good agreement with the simulations, with an axial ratio lower than 1.8 dB within the 19.2-30 GHz band. The proposed polarizing reflector can be used for novel multibeam antenna configurations to produce multispot coverage in Ka-band with a smaller number of apertures.