Design and Performance Characteristics of High-frequency Antenna Arrays for 6G Wireless Network

Abstract

Millimeter-Wave (mmWave) and sub-mmWave technology have tremendously advanced in the past decade. The need for adaptability in bandwidth, gain, efficiency, conformity, compactness, sustainability, affordability and commercialization has been the main driver of proposing antenna designs. The challenge lies in achieving the optimal balance between sustainability, compactness, operating frequency, bandwidth and gain for practical deployment, which is crucial in next-generation antenna technologies. Therefore, this thesis aims to introduce four antenna designs that can tackle these challenges.

A flexible, skin-friendly natural fiber is chosen as substrate material to fit the zero-waste, eco-friendly antenna requirements alongside biodegradable graphene. Novel antenna structures have been developed incorporating co-planar waveguide (CPW), defected ground structure (DGS) and partial background elements specifically designed for mmWave applications. This research proposes antenna geometries on flexible and rigid substrates respectively with extension to Multiple-Input Multiple-Output (MIMO) and antenna array topology.

Firstly, an environmentally safe, conformal antenna is presented based on a CPW design utilizing radiation guiding stubs. Secondly, a dual-band CPW antenna with DGS enhanced partial ground is proposed to disturb the resonance in the current flow while keeping the design structure size within 1 cm2. Thirdly, another CPW design is discussed that reaches a 9.9 GHz wide bandwidth on the Q-band and the lower frequencies of the V-band. It integrates MIMO technology, extending the pattern to four orthogonal antenna elements yielding high isolation, and the Envelope Correlation Coefficient (ECC) being below 0.012 between each antenna port. Lastly, a simulated and fabricated antenna with DGS elements operating on K and Ka-band between 25.75 - 34 GHz frequency gives gain values of above 3.5 dBi reaching a maximum of 4.7 dBi. The success of this design resulted in an antenna array simulation and fabrication to be measured in the future. Finally, these approaches anticipate potential contributions towards integration and realization of metamaterial antennas for beam steering and reconfigurable antennas for beam switching in beyond 5G and 6G wireless networks, surveillance and communication devices. Overcoming the challenges of balancing compactness, efficiency, and practical deployment, the presented research offers profound insights, making a substantial contribution to the innovation, transformation and continued advancements of beyond 5G communication systems.

Date of Award	2025
Original language	English
Awarding Institution	Aberystwyth University
Supervisor	Syeda Fizzah Jilani (Supervisor) & Andrew Evans (Supervisor)