Array antennas with reconfigurable frequency and polarization, as well as beam-steering capabilities, have become essential for modern wireless systems. Beyond potential cost and space savings, these versatile antennas are expected to enhance both the performance and the security of wireless communication. Traditional designs rely on a large number of active elements for this purpose, resulting in an expensive solution that also leads to complex feeding and biasing networks. Alternatively, reconfigurable operation in microwaves can be achieved through magnetic tuning of ferrite substrates, eliminating the need for active components. Further cost savings can be achieved if additive manufacturing is adopted. These two approaches will be utilized in this dissertation to develop a cost-effective and structurally simple phased array antenna with the desired level of versatility.

IoT devices at the edge of the network are energy-constrained, and a significant portion of power is wasted on non-essential radiation when large coverage antennas are implemented. Additionally, continuous and uncontrolled electromagnetic (EM) radiation contributes to ambient EM pollution. When combined with the projected growth of IoT devices, this raises the chances of interference between devices, leading to potential information loss in dynamic scenarios.

We will discuss the solution of eigenvalue problems associated with partial differential equations (PDE)s that can be written in the generalised form Ax = λMx, where the matrices A and/or M may depend on a scalar parameter. Parameter dependent matrices occur frequently when stabilised formulations are used for the numerical approximation of PDEs. With the help of classical numerical examples we will show that the presence of one (or both) parameters can produce unexpected results.

With the rapid development of wireless mobile communication technologies, there has been a growing demand for high data-rate communication in the mmWave range of 5G bands and future 6G bands due to their much larger available bandwidths. Despite their potential, these frequency ranges suffer from significant atmospheric attenuation, necessitating antennas with high gain and wide beam-scanning capabilities to ensure robust coverage. Thus, there is a need to develop compact, high gain, wideband, and wide beam-scanning mmWave antenna/array for 5G/6G applications.

Hessian-dependent functionals play a pivotal role in a wide latitude of problems in mathematics. Arising in the context of differential geometry and probability theory, this class of problems find applications in the mechanics of deformable media (mostly in elasticity theory) and the modelling of slow viscous fluids. We study such functionals from three distinct perspectives.

We present a theoretical analysis of the Weak Adversarial Networks (WAN) method, recently proposed in [1, 2], as a method for approximating the solution of partial differential equations in high dimensions and tested in the framework of inverse problems. In a very general abstract framework.

Analogies between financial markets and critical phenomena have long been observed empirically. So far, no convincing theory has emerged that can explain these empirical observations. Here, we take a step towards such a theory by modeling financial markets as a lattice gas.

Wave propagation and scattering problems are of huge importance in many applications in science and engineering - e.g., in seismic and medical imaging and more generally in acoustics and electromagnetics.

In this short course, we will introduce some elements in deriving the hp a posteriori error estimate for a high-order unfitted finite element method for elliptic interface problems. The key ingredient is an hp domain inverse estimate, which allows us to prove a sharp lower bound of the hp a posteriori error estimator.

Although technical challenges are still daunting, the clinical utility of neuroprosthetics has increased dramatically over the past few years. This has been accomplished through the convergence of numerous disciplines, which have individually added fundamental understanding/capabilities to systems that interface with the human body to restore senses and movement, or treat prevalent diseases that have currently no foreseeable cure. Among these, predictive multiscale computational modeling methods have greatly aided in the design of neuroprosthetics by embracing the complexity of the nervous system, which span multiple spatial scales, temporal scales, and disciplines. In this talk, we will cover some of the recent advances in bioelectromagnetic systems for healthcare, with a particular focus on visual and hippocampal prosthesis, peripheral neuroprosthetics, and sensors.

This dissertation presents two different kind of ambient energy harvesters, namely radio frequency (RF) energy harvester (RFEH) and a thermal energy harvester (TEH), which after their individual optimized designs are synergistically integrated into a multi-source energy harvester (MSEH).

With the advent of wearable sensors and internet of things (IoT) applications, there is a new focus on electronics which can be compact, light-weight and flexible so that these can be worn or mounted on non-planar objects. Due to large volume (billions of devices), it is required that the cost is extremely low, to the extent that they become disposable. In the context of miniaturization and lower cost, concepts such as System-on-chip (SoC) where a complete system is realized on a single chip (integrated circuit (IC)) or System-on-package (SoP) where the package of the chip is made functional are beneficial. The flexible and low-cost aspects can be addressed through additive manufacturing technologies such as inkjet and screen printing. Two important aspects of any IoT system, “Sensing” and “Wireless Communication”, will be the focus of this talk. The SoC part of the talk will focus on integration of the antenna on the chip and ways of enhancing its efficiency despite the lossy Silicon substrate in conventional semiconductor manufacturing processes. Through a SoP design example, it will be shown how smart packaging of a chip can boost the performance without adding any additional components or cost. In the later part of the talk, additive manufacturing will be introduced as an emerging technique to realize low cost and flexible wireless communication and sensing systems. Various novel functional inks, such as conductive, dielectric, phase change and sensing materials will be shown. A multilayer process will be presented where dielectrics are also printed in addition to the metallic parts, thus demonstrating fully printed components. Finally, some printed sensor examples will be shown for remote health and environmental monitoring. The promising results of these designs indicate that the day when electronics can be printed like newspapers and magazines through roll-to-roll printing is not far away.

The technological evolution has led to the current high-performing wireless communication systems that we use on a daily basis. However, coping with the increasing demand is becoming more and more challenging, especially since we are approaching the limits of what can be done with the available resources. One of these resources is bandwidth. This spectrum scarcity problem has motivated researchers to explore new frequencies for wireless communications. Due to this reason, the upper radio-frequency (RF) spectrum, from mmWave and THz to optical bands, is being pursued, which is termed as “Extreme Bandwidth Communication.” This conference brings world experts and the brightest minds from academia and industry to present the latest trends, challenges, results, and opportunities in the field of extreme bandwidth communication.

Billions of IoT devices will need to communicate with each other in a wireless fashion in the future. Thus, new antenna designs, which perform irrespective of their orientation and position, and can be mass manufactured at lower costs are required. This work presents the theory and design of antennas with near isotropic radiation performance which can be additively manufactured on the packaging of the circuits.

Frequency-reconfigurable RF components are highly desired in a wireless system because a single frequency-reconfigurable RF component can replace multiple RF components to reduce the size, cost, and weight. Typically, the reconfigurable RF components are realized using capacitive varactors, PIN diodes, or MEMS switches, which are expensive, require tedious soldering steps, and are rigid and thus non-compatible with futuristic applications of flexible and wearable electronics. In this work, we have demonstrated vanadium dioxide (VO₂) based RF switches that have been realized through additive manufacturing technologies (inkjet printing and screen printing), which dramatically brings the cost down to a few cents. Also, no soldering or additional attachment step is required as the switch can be simply printed on the RF component. The printed VO₂ switches are configured in two types (shunt configuration and series configuration) where both types have been characterized with two activation mechanisms (thermal activation and electrical activation) up to 40 GHz. The measured insertion loss of 1-3 dB, isolation of 20-30 dB, and switching speed of 400 ns is comparable to other non-printed and expensive RF switches. Moreover, as an application for the printed VO₂ switches, a fully printed frequency reconfigurable filter has also been designed in this work.

This seminar will review the development of electromagnetic surfaces, as well as state-of-the-art concepts and designs. Detailed presentations will be provided on their unique electromagnetic features. Furthermore, a wealth of practical examples will be presented to illustrate promising applications of the surface electromagnetics in microwaves and optics.

Modern industries are adapting smart ways of monitoring their processes to ensure smooth operations. Sensors capable of early detection of a problem are becoming the norm in industrial processes.  This is key to the development of the “Internet of Things” (IoT), in which billions of interconnected devices will work together to make smart decisions. Sensors that can detect and communicate the process information are essential ingredients of any IoT-enabled network. Since billions of such sensor nodes will be required in the future, the low cost will be an important feature for these devices. Consistent with the above-mentioned trends, the oil industry is also adapting smart monitoring and actuation mechanisms for its day-to-day operations.  This thesis is focused on developing low-cost sensors, which can increase oil production efficiency through real-time monitoring of oil wells and also help in the safe transport of oil products from the wells to the refineries.