Design of Dual-Polarized All-Dielectric Transmitarray Antenna for Ka-Band Applications

This paper proposes two all-dielectric transmitarrays operating at Ka-band (26.5–40 GHz), achieving dual-polarization and beam-scanning functionalities. The dual-polarized design employs a cross-shaped dielectric post transmission unit, where the lengths of the two posts can be adjusted to enable independent phase modulation in the two orthogonal polarizations. Both polarizations provide 360° continuous phase coverage. To reduce the design complexity and achieve independent control of polarization, an optimized unit group with 16 states and 2-bit phase quantization is developed. A prototype of the all-dielectric transmitarray with 20 × 20 units is fabricated. The measured x/y-polarized peak gains are 25.3 dBi/25.5 dBi and the 1 dB bandwidths achieve 27% and 22%, respectively. To address feed–array integration, another all-dielectric transmitarray is further designed, which uses the same dual-polarized dielectric units, but replaces the horn feed with a dielectric rod antenna array. The feed array can generate multiple beams, enabling discrete beam-scanning within a 60° angle range. Both the dielectric transmitarray and the feed array can be fabricated by using 3D-printed technology, which greatly enhances the system integration and provides flexibility in generating multiple high-gain beams.