A Single-Fed Dual-Band Orthogonal Circularly Polarized Filtering Antenna for 5G-Enabled IoV Applications

A single-fed dual-band antenna with orthogonal circular polarizations (CPs) and filtering responses in its two bands is proposed for Internet of Vehicle (IoV) communications. To suppress unwanted out-of-band signals, a folded stepped-impedance aperture is integrated to achieve dual-band filtering response, while maintaining a simple structure without adding filtering circuits. In addition, a dual-branch feedline is adopted to improve impedance matching and filtering response of the antenna efficiently. Moreover, a merged structure technique of modified dielectric resonator and slot aperture is employed to overcome the challenge of single-fed orthogonal CP waves in the two bands, enabling low inter-channel crosstalk for compact vehicular wireless systems. A phase control method is studied for independent control of orthogonal CPs in the two bands. Subsequently, the CP performance and radiation gain are further improved by the modified dielectric resonator for robust links. For demonstration, an antenna prototype is designed and fabricated, operating in the bands of 1.75 and 2.6 GHz with left-handed CP (LHCP) and right-handed CP (RHCP), respectively. The measured results show reasonable agreement with the simulated ones. With the merits of high-integration, multi-function, simple structure, and compact size, the proposed antenna can be an attractive candidate for IoV communication systems.