Millimeter-Wave Components and Antennas for Spatial and Polarization Diversity using PRGW Technology

The evolution of the wireless communication systems to the future generation is accompanied by a huge improvement in the system performance through providing a high data rate with low latency. These systems require access to millimeter wave (mmWave) bands, which offer several advantages such as physically smaller components and much wider bandwidthcomparedtomicrowavefrequencies. However, mmWavecomponentsstillneed a significant improvement to follow the rapid variations in future technologies. Although mmWave frequencies can carry more data, they are limited in terms of their penetration capabilities and their coverage range. Moreover, these frequencies avoid deploying traditional guiding technologies such as microstrip lines due to high radiation and material losses. Hence, utilizing new guiding structure techniques such as Printed Ridge Gap Waveguide (PRGW) is essential in future mmWave systems implementation. ThemainpurposeofthisthesisistodesignmmWavecomponents,antennasubsystems and utilize both in beam switching systems. The major mmWave components addressed in this thesis are hybrid coupler, crossover, and differential power divider where the host guidingstructureisthePRGW.Inaddition,variousdesignsfordifferentialfeedingPRGW antennas and antenna arrays are presented featuring wide bandwidth and high gain in mmWave band. Moreover, the integration of both the proposed components and the featured antennas is introduced. This can be considered as a significant step toward the requirements fulfillment of today's advanced communication systems enabling both space and polarization diversity. The proposed components are designed to meet the future ever-increasing consumer experience and technical requirements such as low loss, compact size, and low-cost fabrication. This directed the presented research to have a contribution into three major parts. The first part highlights the feeding structures, where mmWave PRGW directional couplers and differential feeding power divider are designed and validated. These components are among the most important passive elements of microwave circuits used in antennabeam-switchingnetworks. Different3-dBquadraturehybridcouplersandcrossover prototypes are proposed, featured with a compact size and a wide bandwidth beyond 10 % at 30 GHz. In the second part, a beam switching network implemented using hybrid couplers is presented. The proposed beam switching network is a 4 × 4 PRGW Butler matrix that used to feed a Magneto-electric (ME) dipole antenna array. As a result, a 2-D scanning antenna array with a compact size, wide bandwidth, and high radiation efficiency larger than84%isachieved. Furthergainenhancementof5dBiisachievedthroughdeployinga hybridgainenhancementtechniqueincludingAMCmushroomshapesaroundtheantenna array with a dielectric superstrate located in the broadside direction. The proposed scanning antenna array can be considered as a step toward the desired improvement in the data rate and coverage through enabling the space diversity for the communication link. The final activity is related to the development of high-gain wide-band mmWave antenna arrays for potential use in future mmWave applications. The first proposed configuration is a differential feeding circular polarized aperture antenna array implemented with PRGW technology. Differential feeding antenna designs offer more advantages than single- ended antennas for mmWave communications as they are easy to be integrated with differential mmWave monolithic ICs that have high common-mode rejection ratio providing an immunity of the environmental noise. The proposed differential feeding antenna array is designed and fabricated, which featured with a stable high gain and a high radiation efficiency over a wide bandwidth. Another proposed configuration is a dualpolarized ME-dipole PRGW antenna array for mmWave wireless communication. Dual polarizationisconsideredoneofthemostimportantantennasolutionsthatcansavecosts and space for modern communication systems. In addition, it is an effective strategy for multiple-input and multiple-output systems that can reduce the size of multiple antennas systems by utilizing extra orthogonal polarization. The proposed dual- polarized antenna array is designed to achieve a stable gain of 15 ± 1 dBi with low cross- polarization less than -30 dB over a wide frequency range of 20 % at 30 GHz

Low-Profile Wideband Antenna Arrays for Mobile Satellite and 5G Communication

Three innovative low-profile antenna arrays are designed and tested for vehicular satellite and 5G communication. All of the systems presented target key challenges of GEO, LEO and 5G communication. Each design provides a high level of performance for the given application in a far more compact and lower cost design than existing systems.Firstly, a wideband curl antenna array is developed to enable L-band GEO satellite communication for emergency vehicles. This novel 1×3 rotated array utilises a hybrid switch beam and phase shifting technique to enable full beamforming down to 70° in all directions with 40% lower cost than standard phased array systems. Uniquely, this provides excellent azimuth beam steering at low angles from a linear array. This system also utilises a high impedance surface to reduce the height of the antenna elements by 50% compared to existing curl antenna designs.Secondly, a shared aperture antenna array is developed to enable Ka-band LEO satellite communication for vehicular integration. This system utilise a new combination of circular polarised triangular antennas in an interlaced planar triangular lattice such that the topology provides optimal tessellation. As a result, the system provides high performance beam steering and reconfigurable circular polarisation in a highly compact design. This array has been developed such that it is suitable for common PCB manufacturing methods. Unlike existing shared aperture arrays for LEO terminals, this topology enables reconfigurable circular polarisation in a single, planar PCB structure.Finally, a low-cost wideband compressed spiral antenna array is designed and fabricated for global 5G ground-to-air communication for aircraft. An innovative spiral antenna optimisation is presented where the spiral is highly compressed such that it can provide an axial beam over a wide bandwidth while maintaining a lower profile than existing wideband solutions

Advanced Radio Frequency Antennas for Modern Communication and Medical Systems

The main objective of this book is to present novel radio frequency (RF) antennas for 5G, IOT, and medical applications. The book is divided into four sections that present the main topics of radio frequency antennas. The rapid growth in development of cellular wireless communication systems over the last twenty years has resulted in most of world population owning smartphones, smart watches, I-pads, and other RF communication devices. Efficient compact wideband antennas are crucial in RF communication devices. This book presents information on planar antennas, cavity antennas, Vivaldi antennas, phased arrays, MIMO antennas, beamforming phased array reconfigurable Pabry-Perot cavity antennas, and time modulated linear array

Wideband Differentially-Fed Slot Antenna and Array With Circularly Polarized Radiation for Millimeter-Wave Applications

© 2022 IEEE - All rights reserved. This is the accepted manuscript version of the accepted manuscript version of an article which has been published in final form at https://doi.org/10.1109/TAP.2022.3145481A wideband differentially-fed slot antenna is presented for millimeter-wave (mmWave) applications. A novel method of using stepped corner-shaped slot is first utilized to establish the wideband circularly polarized (CP) radiation. In the configuration of corner-shaped slot, two wide open slots at the ends are utilized for effective orthogonal radiation, while the narrow slot at the center is utilized for power transmission and quadrature phase delay. An equivalent circuit is given to illustrate the inner working principle for CP radiation. In addition, square cuts are etched on the four corners of the radiating patches to further increase the axial ratio (AR) and impedance bandwidth. Based on this design concept, the antenna element was first designed and fabricated for performance verification. Then, a 1×4 linear array with beam scanning performance and a 4×4 planar array with high gain and stable radiation were designed and fabricated. Both the simulated and measured results show that the 1×4 linear array and 4×4 planar array can have wide overlapped impedance and AR bandwidths of 30.6% and 33.6% with thickness of 0.16λ0. The advantages of compact size and wide bandwidth make the presented antenna a good candidate for mmWave applications.Peer reviewedFinal Accepted Versio

Simple wideband extended aperture antenna-inspired circular patch for V-band communication systems

This article presents the design and realization of compact, geometrically simple, wideband and high gain antenna for V-band communication systems. The antenna is designed by using a conventional circular patch, which is further modified by using another fractal circular patch. Furthermore, the addition of three elliptical shaped patches significantly increases the bandwidth of the antenna. Afterwards, a circular slot is etched from the radiator to improve the radiation pattern of the antenna. The proposed structure comprises of an overall substrate size of 13 × 12 × 0.508 mm3 and designed using Duroid 5880 having very low loss tangent of 0.0009. To verify the presented results, the antenna prototype is fabricated and tested. The comparison among simulated and measured results shows a strong performance. Moreover, the comparison with state of the artwork shows that the antenna offers compact size, wide bandwidth, high gain, and good radiation efficiency. Thus, it makes the proposed antenna a potential candidate for the V-band communication systems.The authors sincerely appreciate the funding from Universidad Carlos III de Madrid and the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie Grant 801538. Also, this work is partially supported by Antenna and Wireless Propagation Group (AWPG); https://sites.google.com/view/awpgrp, and from the Researchers Supporting Project number (RSP-2021/58), King Saud University, Riyadh, Saudi Arabia