Dual Frequency Dual Polarized Antenna Fed by Substrate Integrated Coaxial Line for 5G Millimeter Wave Application

This paper presents a novel dual-frequency antenna design in Substrate Integrated Coaxial Line (SICL) technology, which exhibits dual-polarization capabilities for 5G mmWave application. A folded patch is designed using metallic post connected to both top and middle layer in the top substrate of SICL. The surface current and radiation patterns are analyzed to provide confirmation of both linear and circular polarization in the proposed antenna. To have broadside radiation, the bottom ground layer of the SICL is extended. The classical printed half-wavelength dipole antenna is designed at 28 GHz by feeding one dipole arm from the top layer and the other arm by the middle layer of the SICL. The novel antenna formed by the proposed co-located dipole and folded patch in this study exhibits a dual-frequency operation at 26.1 GHz and 29.85 GHz respectively. The designed antenna demonstrates linearly polarized unidirectional broadside beam with a gain of 6.5 dBi at first operating frequency 26.1 GHz and 3.2 dBic broadside LHCP gain at second operating frequency 28.95 GHz. This study showcases the efficacy of SICL in design of the proposed antenna and its feeding network, enabling simultaneous dual-frequency dual-polarized operation, rendering it well-suited for mmWave applications.