Dielectric Resonator Antennas-Based MIMO/mm-Wave Array Design

Abstract

The new wireless standard 5G is a significant leap beyond 4G in architecture, implementation, and envisioned services. The new wireless standard is setting the stage for the successful implementation of new technologies, e.g., IoT, smart cities, autonomous vehicles, etc., by guaranteeing low latency, massive connectivity, and extremely high data rates. An essential part of a 5G system is the antenna design compatible with its requirements. Due to the use of widely spaced frequency bands for 5G and specific radiation characteristics in different communication scenarios, antenna design is highly challenging. This thesis aims to develop a multiband antenna for 5G bands that are largely separated. Moreover, to meet the complexities and requirements of each band, the primary outcome of this work is an integrated, structure re-use, dielectric resonator antenna (DRA) solution that comprises of 2 element MIMO-based radiating elements at sub-6 GHz band and a 1×4 array at millimeter waves, and covers largely separated 5G n79 (4.4-5 GHz) and n261 (27.5-28.35 GHz) bands. The antenna consists of 2 element rectangular Dielectric Resonator Antenna (rDRA)-based MIMO antenna to cover the sub-6 GHz band, in which a 1×4 cylindrical Dielectric Resonator Antenna (cDRA) array is embedded for covering the mmW band. Metallic plates are glued with each of the rDRA sides that face cDRAs, to isolate the radiators of both bands. In addition, these plates also help in the spatial decorrelation of the MIMO elements. The sub-6 GHz rDRA elements are fed by edge coupled strip, whereas the mmW array is fed through aperture coupling of a 1×4 T-junction power divider. The mmW power divider is implemented beneath rDRA elements by utilizing GCPW technology for the transmission lines of both bands and benefitting from the fact that the top copper layer of the substrate only acts as a ground plane for DRA elements. Due to this, the complete antenna occupies an area of 60 mm×60 mm, which includes all of the feed networks, rDRAs, and cDRAs. To verify the design process of the antenna, its prototype is fabricated and xv List of Tables thoroughly measured at PolyGrames, Canada. The measured impedance bandwidth of the antenna at the center frequencies of 4.7 and 28 GHz is 12.7% and 21.5%, respectively. The measured peak gain of the antenna at sub-6 GHz and mmW frequencies is 6.6 dBi and 12 dBi, respectively. Moreover, the beam steering performance of the antenna has also been verified in simulations, which exhibits good performance for the sector of ±50◦. Overall, the measured results verify the design procedure and implicate the usefulness of the proposed antenna solution for 5G applications.