LAUSR

A low-profile dual-band composite structure antenna is proposed for fifth generation mobile communication system (5G), which is named as Antenna on Antenna (AOA). Loaded with an artificial magnetic conductor (AMC) reflector, the proposed AOA element consists of a pair of dual-polarized lower band (LB) dipole antennas working in the 0.7–1.03 GHz band and four upper band (UB) patch antenna arrays working in the 24.25–27 GHz band, which covers LTE and 5G millimeter wave band. In order to reduce the size of base station antenna, the millimeter wave patch antenna arrays are parasitic on LB dipoles. While the radiator of the LB antenna is utilized as the ground of the millimeter wave patch antenna array, LB and UB antennas share the same dielectric substrate. The profile height of the antenna is reduced by AMC reflector effectively. Meanwhile, the three-element AOA array loaded with AMC reflector is designed to validate the overall performance of base station antenna. The operation bands of the proposed AOA are 0.7–1.03 GHz (Snn < −14 dB) and 24.25–27 GHz (Snn < −10 dB) for LTE and 5G millimeter bands, respectively. Antenna prototype was fabricated and measured to verify the design solution. The measured results which are consistent with simulated results show that the AOA has good impedance matching, port isolation, and stable radiation pattern.