Compact Triple-Band Circularly Polarized Rectangular Dielectric Resonator Antenna for Sub-6 GHz Applications

— This work presents a compact triple-band circularly polarised (CP) rectangular dielectric resonator antenna (RDRA) optimised for Sub-6 GHz fifth generation (5G) applications. A novel method is devised to realise the proposed antenna design that enables compactness, triple band operation, and high performance. Two RDRAs working in three different configurations provide CP. Triple-band operation is achieved by the excitation of {TE}_{111} mode (Top and Side view) at frequency 3.75 GHz for RDRA1 and {TE}_{211} mode (Top view) for RDRA2. Compactness is achieved through the hybrid structure and the excitation of modes beyond the fundamental one. It can be seen that the antenna indeed presents gains close to 8.2 dBi with more than 90% radiation efficiency. The design adopted a 72 × 72 mm² FR4 substrate with defected ground structure (DGS) having a cross-slot. RDRA1 is attached to a rectangular patch with a microstrip feed. At the same time, RDRA2 is located on the top of the cross-slot of the ground plane. Designed and simulated from Alumina (Al2O3), RDRAs are optimized to minimize dielectric loss while enhancing energy transfer. The judicious choice of materials and strategic placement of components greatly enhance the antenna's electromagnetic performance, resulting in advanced impedance matching and bandwidth over the target frequency bands.