Low-Profile Dual-Circularly Polarized Antenna Array With Hemispherical Scan Coverage

In this letter, a novel planar antenna array with hemispherical beam-coverage capabilities is proposed. The antenna units are arranged at different positions within a plane, and each unit possesses a specific orientation angle, which is algorithmically optimized to extend the spatial beam-scanning coverage of the antenna array. Compared to traditional spherical arrays and pyramidal arrays, the proposed one can significantly reduce the profile while maintaining hemispherical beam-coverage performance. A prototype of the proposed antenna is fabricated and measured to validate the design. The measured results demonstrate that it can achieve a gain of over 11 dBi for dual circular polarization with an axial ratio of below 3 dB in the operating frequency range of 2.5–3 GHz. Furthermore, the overall profile of the proposed antenna is as small as 0.48
λ₀
(
λ₀
is the free-space wavelength at 3 GHz).