High-Order-Mode Cavity Fed Antenna Arrays for Diverse Polarizations With Compact Size, High Gain, and High Efficiency

In this article, a novel structure of the high-order-mode cavity fed sequentially rotated patch antenna array is proposed for diverse polarizations. The diverse polarizations, including right-hand circular polarization (RHCP), left-hand circular polarization (LHCP), −45° linear polarization (LP), 0° LP, 45° LP, and 90° LP, are achieved based on the current distribution on the patches and different electric field modes in the high-order-mode cavity by adjusting the phase and amplitude of the two orthogonal feeding ports. Furthermore, from the electric field distribution in the high-order-mode cavity with different feeding schemes, arbitrary polarizations were analyzed and obtained. An
$8\,\times \, 8$
dual-circularly polarized (dual-CP) antenna is demonstrated. Good agreement between the simulated and measured results is obtained, validating the design. The experimental results show that the impedance bandwidths (<−10 dB) for the two ports are 14.2% and 13.3%. The 3 dB axial ratio (AR) overlapping bandwidth is 10.5%. The maximum gain is 25 dBic. Attributed to its compact size, high gain, and high efficiency, the presented array is a good candidate for millimeter-wave applications.