Circularly Polarized Phased Array Antenna With 2-D Wide-Angle Scanning Using Heterogeneous Beam Element Technology

Circularly polarized (CP) phased array antennas (PAAs) often face challenges in achieving wide element beams and axial ratio (AR) patterns simultaneously, thereby constraining their scanning ranges. To address this issue, this article introduces heterogeneous beam element (HBE) technology to the CP PAA design, proposing an offset segmented dielectric lens (OSDLs) beam tilting technology for implementing HBEs. By positioning the OSDL offset within the near-field region above one side of the element, the near-field region is partitioned into multiple segments with varying phase differences, achieving element beam tilting. The study provides a comprehensive analysis of the CP HBE PAA design, encompassing the CP element design with a wide spatial AR bandwidth and high isolation, as well as the principle and design guidelines of the OSDL beam tilting technology. Experimental results demonstrate a significant extension of the scanning range compared to the $4 \times 4$ -element CP standard PAA, with improvements ranging from 56° to 75° in the orthogonal plane and from 58° to 80° in the diagonal plane across the 17–20-GHz band while maintaining AR values below 3 dB. The effectiveness and robustness of the OSDL beam tilting technology underscore its potential as a universal HBE implementation approach.