Quad-port circular polarized MIMO dielectric resonator antenna featuring beam tilting for vehicular communication

This paper presents the design and implementation of a quad-port circular polarized Dielectric Resonator Antenna (DRA) with Multiple-Input Multiple-Output (MIMO) capabilities and beam tilting features. The beam tilting feature allows for dynamic adjustment of the radiation pattern, improving signal coverage and reducing interference in complex environments. Beam tilting is achieved, and correlation is minimized in the far-field patterns by positioning a conducting plate between the antenna elements. Measurements indicate that the antenna achieves an Axial-Ratio Bandwidth (ARBW) of 4.69 GHz to 4.84 GHz with an AR of less than 3 dB and an impedance bandwidth from 4.6 GHz to 5.2 GHz. The DRA's resonating frequencies are produced by electromagnetically exciting it through optimized unequal-length loaded cross slots with a microstrip line. All ports are arranged in a parallel configuration. The adjacent ports are 180 degrees out of phase each other. The antenna achieves maximum beam tilting of +/- 30 degrees at 4.82 GHz. Oppositely oriented ports show polarization diversity with Left Hand Circular Polarization (LHCP) and Right Hand Circular Polarization (RHCP). The MIMO DRA's optimal diversity parameters make it ideal for high-speed vehicular Communication and WLAN application.