A Low-Profile Compact Circularly Polarized Broadband mm-Wave Antenna for Indoor IoT Applications

The demand for low-profile broadband antennas that generate CP is increasing, especially for portable and handheld devices, as CP antennas help reduce issues like multipath interference and misalignment. To meet this demand, this article introduces a miniaturized mm-Wave antenna. The design features a novel circular labyrinth maze structure, which consists of a central circular ring and two semi-circular patches. The circular ring is etched with eight T-shaped slots at a 45° angle. The current fed to the circular patch splits into right and left directions, and the T-shaped slots offer a return path for the current with a ±90°differential phase, thus producing circular polarization. The design and analysis of the structure are performed using HFSS v.2024.R1 software. The proposed antenna offers an impedance bandwidth of 13.5 GHz (27.1 to 40.6 GHz), a 3-dB axial ratio bandwidth of 8.08 GHz (30.1 to 38.18 GHz), a maximum gain of 7.47 dBi and radiation efficiency of 97%.