Low Cost Transparent and Flexible Antenna for Next Generation Communication Networks

Next-generation antenna design plays a vital role in enabling technologies in fifth generation (5G) and beyond fifth-generation (B5G) wireless networks. 5G and B5G technologies are envisioned to provide ubiquitous connectivity, enhanced coverage, ultra reliable low latency, and high data rates to meet societal and industrial needs. Furthermore, they are envisioned to unleash the potential of machine-to-machine communication and internet-of-things (IoTs) to build an ecosystem where networks can provide instantaneous connectivity for billions of connected devices. However, one challenge to the wide deployment of such a level of connectivity is that traditional antennas used in the current 4G and 4G-LTE systems are often large and intrusive. The exponential growth in demand for IoT devices, gateways and other wireless modulus, alongside with aesthetics requirement and cost considerations, have driven engineers to research “invisible” optically- transparent antennas and arrays that can be used in access points and signal repeaters embedded into existing urban infrastructure, without spoiling the aesthetic appearance of the environment and architectures. This thesis focuses on development of robust, cost-effective, and ecologically acceptable nanomaterials for optically transparent antennas, intelligent surfaces, and radio-frequency (RF) devices. Particularly, a large-area, ultralow-profile and mechanically-flexible transparent conductive films (TCFs) based on the metal-dielectric nanocomposite (MDNC) will be used to build these key component in next- generation communication systems. Moreover, the optimal design of MDNC, which exhibits high optical transparency and decently low electrical resistivity, will be conducted using the optical nanocircuit theorem and transfer matrix method. The versatility of the MDNC-TCF is demonstrated by implementing various transparent and flexible antennas, in the form of omnidirectional linear dipole, unidirectional Yagi-Uda antenna, microstrip patch antenna, and novel solar-powered body-wearable antenna. This research also studies transparent metasurfaces and their applications in antenna radomes, which can be used in, for example, high-gain and low- RCS Fabry-Perot cavity antennas and solar-powered base station antenna. The results of this thesis will pave the way for the practical realization of low-cost, conformal and optically-transparent antennas and intelligent surfaces that are capable of enhancing and optimizing connectivity of 5G and B5G communication systems.