Design of Multiple-Polarization Transmitarray Antenna Using Rectangle Ring Slot Elements

A multiple-polarization transmitarray using rectangle ring slot elements is presented in this letter. Fed by a linearly polarized Vivaldi antenna, this proposed transmitarray can generate radiation patterns with different polarizations, including left-handed circular polarization, right-handed circular polarization, and vertical and horizontal polarizations. The multiple-polarization characteristic is realized by properly rotating the feed antenna around the center and adjusting the x- and y-dimensions of each element. To validate the performance of the designed antenna, a prime-focus 81-element transmitarray has been fabricated and measured. The experimental results show that the fabricated antenna in the CP mode achieves 3-dB axial-ratio bandwidths of 16.7%, while the antenna in the LP mode achieves 1-dB gain bandwidths of 8.3% with the maximum gain of 20.1 dB. The feature of polarization diversity makes the designed transmitarray suitable for the wireless communication systems.