This communication describes the performance of the dual-circularly polarized transmitarray antennas at the Ka-band with independent radiation characteristics. The proposed antenna architecture consists of a dual-linearly polarized (dual-LP) TA panel based on the interleaving technique combined with an add-on broadband polarizer to generate independent right-handed circular polarization (CP) (RHCP) and left-handed CP (LHCP) beams. This offers both dual-LP and dual-CP operation depending on the topology of the polarizer. The LP unit-cell is designed to achieve a 3 bit phase resolution, and the dual-LP TA panel is made of two interleaved single-LP subarrays with 52 × 52 and 53 × 53 elements operating in 45° and 135° single LP, respectively. The polarizer transforms the dual-LP into dual-CP while keeping the radiation independence of each polarization across the Ka-band. The experimental results obtained with three different prototypes pointing up to 50° validate the proposed concepts.

We present a method to design planar broadband and broad-angle multilayer polarizers. The proposed procedure is based on a hybrid method that combines the analytical transmission line model and the full-wave Floquet analysis in the frequency domain. The unit-cell analysis allows to create a database that relates the geometry with the metasurface impedances. Thus, any kind of geometries (especially those that do not have an equivalent model) can be used. As the database is created for a single-layer structure, the computation time needed for the design process is reduced (compared with the full-stacked unit-cell). As an example, a polarizer is designed as an add-on device that could be integrated to any linearly polarized antenna (without affecting its behavior) to create circular polarization. Experimental results for a five-metasurface-layer design are given, demonstrating insertion loss lower than 0.5 dB and an axial ratio less than 3 dB over the entire band ranging from 24.84 to 30.24 GHz, which corresponds to a fractional bandwidth of 19.6% for an incidence of 0°-50°.