Low-Profile Broadband Circularly Polarized Stacked Magnetoelectric Dipole Antenna and Its Array for Ka-Band Satellite Communications

Abstract

The Ka-band is widely used for satellite communications; however, most existing millimeter-wave (mmWave) circularly polarized (CP) antennas, including dielectric resonator antennas, spiral antennas, and magnetoelectric dipole (ME-dipole) antennas, fail to meet ultrawide bandwidths with profiles less than $0.12\lambda _{0}$ , which limits their suitability. To address this issue, this communication proposes a wideband CP ME-dipole antenna array covering the full Ka-band with a profile of $0.096\lambda _{0}$ . The antenna element integrates two sets of ME-dipoles, consisting of a curved patch pair and a rectangular patch pair, together with parasitic patches. By employing a coupling slot and stacked patches, the element achieves an impedance bandwidth of 62.35% and an axial-ratio (AR) bandwidth of 30.97%. A $2\times 2$ wideband CP antenna array employing a sequential-rotation feeding network is further investigated, fabricated, and measured. The measured overlapped (impedance, AR, and gain) bandwidth covers the entire Ka-band from 24.5 to 40.5 GHz. To the best of the authors’ knowledge, this is the first ME-dipole design that achieves full Ka-band coverage with the lowest profile, demonstrating strong potential for mmWave and satellite communication applications.