Mechanically Steerable Simultaneous Multibeam Transmitarray Design by Analytical Multifocal Approach

A novel design methodology for improving the radiative performance of single-feed simultaneous multibeam transmitarrays (SMBTAs) is presented. Concurrent multibeam scanning is achieved by a linear displacement of the feeder along a line parallel to the transmitarray (TA) surface. The proposed synthesis of the passive TA phase distribution relies on an analytical multifocal (MF) scheme exploiting the minimum mean square error (MMSE) algorithm. A thorough numerical investigation that examines different TA sizes proves the benefits offered by the investigated strategy. Remarkable performance enhancement in terms of scan loss and peak sidelobe level (PSLL) are achieved with respect to the conventional single-focus phase correction approach. Furthermore, a detailed statistical analysis verifies the robustness of the adopted solution. Finally, two dielectric-based TAs radiating a simultaneous dual-main beam at 28 GHz are manufactured and tested to assess the reliability of the proposed methodology.