SIW-Cavity-Backed Wideband Circularly Polarized Antenna Using Modified Split-Ring Slot as a Radiator for mm-Wave IoT Applications

This article proposes a wideband circularly polarized substrate integrated waveguide (SIW) antenna for millimeter-wave (mm-wave) 5G-enabled Internet of Things (IoT) applications. The proposed antenna design comprises of modified circular-shaped split-ring slot and asymmetrically placed shorting metallic vias at three corners of rectangular SIW-cavity. Furthermore, a shorting via is placed adjacent to the edge of the modified slot whose edges are perturbed to support the circular polarization (CP) radiation. The usefulness of the simulation is validated through the testing of the fabricated prototype. The proposed SIW-based antenna features a wide impedance bandwidth of 12.57% (25.72–29.17 GHz), a good axial ratio (AR) bandwidth of 9.69% (25.52–28.12 GHz), and a maximum gain of 8.5 dBic in the operating mm-wave band. Consequently, the suggested SIW antenna design can meet the research need for a wider AR bandwidth in the mm-wave range for 5G-enabled IoT applications.