Single CDR-Based MIMO Antenna Incorporating PDGS and PRS Techniques for Enhanced mmWave Communications

This work presents a comprehensive investigation of a Multiple-Input Multiple-Output (MIMO) antenna incorporating a Perforated Dielectric Gradient Surface (PDGS) and a Partially Reflective Surface (PRS) for millimeter-wave (mmWave) applications. The proposed design is based on a single cylindrical resonator antenna (CDRA) as a resonant element. It operates over the 24 GHz to 29 GHz frequency range and addresses critical challenges such as gain enhancement, mutual coupling suppression, and directional beam shaping. The PDGS introduces localized electromagnetic bandgaps, suppressing surface wave propagation and minimizing inter-port interference, while the PRS facilitates constructive interference, enhancing radiation efficiency and directivity. Extensive simulation and measurement results confirm the effectiveness of the combined PRS and PDGS integration, demonstrating improved reflection parameters, enhanced realized gain (with a peak gain increase of 8 dBi at 27 GHz), and separated radiation patterns ±30° at 26.5 GHz and 28.5 GHz. The design achieves excellent isolation, with coupling parameters consistently below −20 dB and impedance matching across all ports. These results highlight the suitability of the proposed MIMO antenna for next-generation 5G in mmWave spectrum.