Memristor-based computing architecture with advanced signal processing capabilities investigates analogue applications of memristors, particularly in image processing, combining them with conventional electronic circuitry. The concept of memristor (short for memory resistor) was first theorised in 1971 by Prof. Chua while reasoning on the theoretical grounds of of the symmetry of equations governing the fundamental passive circuit theory. This thesis can be split into two parts as follows: i) Memristor Device, Modelling, Characterisation and Programming and ii) Memristor Circuit Applications. In the first part, an overview of the theory of memristors which gives an introductory background is discussed alongside the device modelling to fit experimental data. Electrical characterisation was carried out on fabricated memristors to validate the fundamental fingerprint of these devices and finally, the different programming techniques, particularly the pulse-based technique which was widely used in this work, was exhaustively treated. In terms of applications, starting from a novel memristor-based light to resistance encoder, a more complex architecture based on adaptive background subtraction for scene interpretation used for the analyses of motion and its association to a particular object in the scene is treated in this work. Throughout this thesis, the intention of an overview on the application of memristors in image processing algorithm is emphasised and the last chapter discusses a neural network architecture based on memristors. The intended neural network architecture was trained to perform colour classification targeting applications based on gesture detection. In essence, Memristor-based computing architecture with advanced signal processing capabilities gives an insight into the advantages to come having an hybrid system of standard CMOS image processing techniques with memristive devices particularly in computation-intensive applications requiring high speed and massive parallel signal processing. Typically the realisation of such powerful and dense networks in an integrated circuit with acceptable size which is not resource hungry by using the commonly encountered elements and conventional CMOS technology is becoming increasingly difficult to achieve. Computing architectures based on memristors present the advantages that could help overcome the limitations of an overall implementation with conventional electronic elements.

Sustainable energy and energy harvesting has become a hot research area due to the shortage of fossil energy resources and burning fossil fuels release greenhouse gases in our environment, which is partaking in gradually increasing of surrounding temperature of our environment. Therefore, the penetration of various types of renewable/ distributed sources, onsite storage devices and DC powered appliances has recently focused attention towards DC power distribution in consumer grids to achieve the target of zero/positive energy buildings and communities. As compared to AC micro grid, many recent studies revealed that DC distribution has many advantages over the convectional AC distribution in term of high efficiency, integration of renewable/ distributed sources and storage locally. The objective of this dissertation is to propose reliable, cost-effective, sustainable, scalable DC consumer grid architecture which can integrate not only renewable/ distributed sources and storage, but also fully compatible with the convectional AC distribution network without any significant change or upgrade. In order to achieve this goal, we proposed the DC Transformer (DCT) enabled consumer grid model. The DC Transformer has been regarded as one of the most emerging technologies and it has many advantages over the convectional low frequency AC transformers such as high power density in small area, voltage regulation, reactive power compensation, fault detection and isolation etc. Apart from advantages, DCT required intelligent control algorithm and additional supervisory circuit makes it complicated and expensive. Therefore, in our proposed model we discussed the pros and cons of typical Solid-State transformer topologies already proposed and explained the topology used in the DCT transformer. Furthermore, in state of the art models, authors used three stages of grid operational modes, which is usually based on different factors such as the status of grid connections, State of charge of Battery storage and output power from locally available sources. However, we introduced four stages excluding buffering stage. All stages are depended upon the practical situations consumer grid may face during normal grid operations such as, DCT Isolation mode, if main grid and local generators are not available then how our proposed model would manage the locally available storage. Main grid interactive mode, we discussed the existing or convectional grid operational condition. In case of no local generator available and the AC main is the only source of power. Self-reliance grid operation, when the renewable energy sources are generating enough energy to fulfil demand side power requirements. Moreover, we explain the safest transition technique from grid connected mode to self-reliance mode without effecting overall grid stability and reliability, called buffer state. Power sharing mode, in this mode we discussed how the locally consumer grid would share surplus energy with adjacent consumer grids without effecting or compromising its own stability. The purpose of proposing critical operational modes and defining the rigid criteria between transitions of each mode is to operate whole grid flawlessly in any real time condition. Moreover, we introduced “Buffer stage†in between the grid connected and self-reliance mode to take into account that renewable sources are stochastic in nature and to avoid any grid stability issue. The operational modes are among key techniques of our proposed architecture and the detail contribution of our proposed model is mentioned in section $1.7.3$. Some practical issues related to the DC micro grid are also examined in detail, such as overall grid control algorithm, power management strategy, demand side management, fault isolation and rectification are highlighted and the solution of these issues also presented with detail simulation results. Furthermore, the state of art DC grid models are proposed for specific type of renewable source(s) such as PV, wind or combination of both. In our proposed architecture, we are not depending on any specific type of renewable and distributed source or storage. We proposed the standard interfaces for possible type of renewable /distributed sources, storage and grid connection. Therefore, by using the standard interface any type of the source and storage can be plug-n-play in PCmRC model. However, the main objectives are to maximize the exploitation of renewable-sources, to decrease reliance on fossil-fuel, to boost the overall efficiency of the grid by reducing the power-conversion losses and full management of end user demand in all possible forms. The simulation platform is designed in MATLAB/Simulink. Several types of case studies and simulation results show the effectiveness of the proposed power distribution and management model.

Terahertz gap corresponding to the frequency band of 0.3-3.0 THz is historically the last unexplored region of the electromagnetic spectrum left to be fully investigated. The major difficulty that has hampered the maturation of technologies operating in this region lies in the fact that much unlike its bordering millimeter and infrared regions, generation and detection of THz radiation is not trivial. Yet, such is the intriguing nature and properties of the terahertz radiations that the interest in this region has not faded. Infact, potential applications of THz based systems have emerged in various fields including biomedical imaging, safety and security, quality control and communication. Over the past decade, a lot of research work has been published with an aim to bridge this gap by both electronics and photonics based systems. While these attempts have succeeded to a certain extent, the available solutions either lack in terms of performance or are mostly bulky and difficult to integrate for portable and commercial purpose. This PhD dissertation focuses on the design and investigation of direct terahertz detectors which could be operated at room temperature and fabricated in standard silicon technologies, thereby making use of several advantages like high level of integration, low cost and small device size that these technologies have to offer. In particular, the emphasis is on developing and characterizing terahertz systems for imaging application by using field effect transistor devices as detectors. This objective is pursued in three parts. The first part (chapter 3) of the dissertation deals with the measurement and characterization challenges of terahertz systems. Unlike guided mode solutions, measurements of terahertz detectors and their systems require free space which presents several challenges due to atmospheric attenuation, spurious reflections and diffractions, beam shaping, and so on. Moreover, background noise is also significant considering that the detected signal is typically in the order of a few microvolts. In this regard, an overview of the most common techniques is given and a measurement methodology involving the use of a reference pyroelectric detector to measure the impinging input power and techniques for the evaluation of the detector under-test effective area is presented. The second part (chapter 4) is related to the investigation of variants of antenna-coupled field effect transistor and schottky barrier diode in standard 180 nm CMOS process as examples of direct detectors. During laboratory characterization, detection of terahertz radiation from schottky diode could not be achieved due to matching issues. Moreover, optimization of schottky diode by modifying its standard cell proved to be challenging as compared to field effect transistor, which can be optimized easily to enhance performance parameters and was therefore finally chosen as the preferred choice. The final part of the thesis (chapters 5 and 6) concerns with the implementation of analog readout interface to perform signal processing of detected terahertz signal. First, a single pixel consisting of on-chip antenna-coupled detector and a switched capacitor based filtering operation is designed and fabricated in 0.15Î1⁄4m process. The pixel is tested by performing both electrical and terahertz characterization, achieving high voltage responsivity value of 470 kV/W and a minimum NEP of 480 pW/sqrt (Hz). The interface architecture is highly repeatable and it can be used with any commercially terahertz source, even if its operation is limited by low modulation frequency. On the basis of the successful measurement results, an 8 x 6 terahertz array for real-time imaging application is fabricated in the same technology by modifying the interface architecture to make it power and area efficient.

This doctorate thesis focuses on the application of micromachining fabrication technologies for the realization of Radio Frequency (RF) bandpass filters. The work has been inspired and supported by the European Space Agency (ESA) Contract No. 22706/09/NL/GLC of the ARTES 5 Workplan 2008 “Micro-machined Filters in Multi-layer Technology for Satellite On-board Communication Systems†(MIGNON Project). The main purpose of the project is the design and realization of high performance bandpass filters in the Ka and L/S band for on board applications. The use of modern micromachining technologies should allow for space and weight reduction as well as for a cost effective realization of these devices. In addition the tight tolerances obtained with micromachining techniques facilitate an industrial fabrication of filters with high yield. The thesis proposes novel concepts to accomplish this task and provides also the fabrication processes suitable to realize the devices. In addition this work gives also a deeper insight into critical fabrication steps like wafer to wafer thermocompression bonding using gold (Au) and silver (Ag) as an intermediate layer and fabrication of Through Silicon Vias (TSV).

Renewable Energy is considered as an effective solution for relieving the energy crisis and reducing the greenhouse gas emissions. It is also be recognized as an important energy resource for power supplying in the next generation power grid{smart grid system. For a long time, the unsustainable and unstable of renewable energy generation is the main challenge to the combination of the renewable energy and the smart grid. The short board on the utilities' remote control caused low-efficiency of power scheduling in the distribution power area, also increased the difficulty of the local generated renewable energy grid-connected process. Furthermore, with the rapid growth of the number of electrical vehicles and the widely established of the fast power charging stations in urban and rural area, the unpredictable power charging demand will become another challenge to the power grid in a few years. In this thesis we propose the corresponding solutions for the challenges enumerated in the above. Based on the architecture of terminal power consumer's residence, we introduce the local renewable energy system into the residential environment. The local renewable energy system can typically support part of the consumer's power demand, even more. In this case, we establish the architecture of the local smart grid community based on the structure of distribution network of the smart grid, includes terminal power consumer, secondary power substation, communication links and sub data management center. Communication links are employed as the data transmission channels in our scheme. Also the local power scheduling algorithm and the optimal path selection algorithm are created for power scheduling requirements and stable expansion of the power supply area. Acknowledging the fact that the information flow of the smart grid needs appropriate communication technologies to be the communication standards, we explore the available communication technologies and the communication requirements and performance metrics in the smart grid networks. Also, the power saving mechanism of smart devices in the advanced metering infrastructure is proposed based on the two-state-switch scheduling algorithm and improved 802.11ah-based data transmission model. Renewable energy system can be employed in residential environment, but also can be deployed in public environment, like fast power charging station and public parking campus. Due to the current capacity of electrical vehicles (EV), the fast power charging station is required not just by the EV drivers, but also demanded by the related enterprises. We propose a upgraded fast power charging station with local deployed renewable energy system in public parking campus. Based on the queueing model, we explore and deliver a stochastic control model for the fast power charging station. A new status called "Service Jumped" is created to express the service state of the fast power charging station with and without the support from the local renewable energy in real-time.

A Wireless Sensor Network (WSN) is a distributed collection of resource constrained tiny nodes capable of operating with minimal user attendance. Due to their flexibility and low cost, WSNs have recently become widely applied in traffic regulation, fire alarm in buildings, wild fire monitoring, agriculture, health monitoring, building energy management, and ecological monitoring. However, deployment of the WSNs in difficult-to-access areas makes it difficult to replace the batteries - the main power supply of a sensor node. It means that the power limitation of the sensor nodes appreciably constraints their functionality and potential applications. The use of harvesting components such as solar cells alone and energy storage elements such as super capacitors and rechargeable batteries is insufficient for the long-term sensor node operation. With this thesis we are going to show that long-term operation could be achieved by adopting a combination of hardware and software techniques along with energy efficient WSN design. To demonstrate the hardware power management, an energy scavenging module was designed, implemented and tested. This module is able to handle both alternating current (AC) based and direct current (DC) based ambient sources. The harvested energy is stored in two energy buffers of different kind, and is delivered to the sensor node in accordance with an efficient energy supply switching algorithm. The software part of the thesis presents an analytical criterion to establish the value of the synchronization period minimizing the average power dissipated by a WSN node. Since the radio chip is usually the most power hungry component on a board, this approach can help one to decrease the amount of power consumption and prolong the lifetime of the entire WSN. The following part of the thesis demonstrates a methodology for power consumption evaluation of WSN. The methodology supports the Platform Based Design (PBD) paradigm, providing power analysis for various sensor platforms by defining separate abstraction layers for application, services, hardware and power supply modules. Finally, we present three applications where we use the designed hardware module and apply various power management strategies. In the first application we apply the WSN paradigm to the entertainment area, and in particular to the domain of Paintball. The second one refers to a wireless sensor platform for monitoring of dangerous gases and early fire detection. The platform operation is based on the pyrolysis product detection which makes it possible to prevent fire before inflammation. The third application is connected with medical research. This work describes the powering of wireless brain-machine interfaces.

The Terahertz (THz) band of the electromagnetic spectrum, also defined as sub-millimeter waves, covers the frequency range from 300 GHz to 10 THz. There are several unique characteristics of the radiation in this frequency range such as the non-ionizing nature, since the associated power is low and therefore it is considered as safe technology in many applications. THz waves have the capability of penetrating through several materials such as plastics, paper, and wood. Moreover, it provides a higher resolution compared to conventional mmWave technologies thanks to its shorter wavelengths. The most promising applications of the THz technology are medical imaging, security/surveillance imaging, quality control, non-destructive materials testing and spectroscopy. The potential advantages in these fields provide the motivation to develop room-temperature THz detectors. In terms of low cost, high volume, and high integration capabilities, standard CMOS technology has been considered as an excellent platform to achieve fully integrated THz imaging systems. In this Ph.D. thesis, we report on the design and development of field effect transistor (FET) THz direct detectors operating at low THz frequency (e.g. 300 GHz), as well as at higher THz frequencies (e.g. 800 GHz – 1 THz). In addition, we investigated the implementation issues that limit the power coupling efficiency with the integrated antenna, as well as the antenna-detector impedance-matching condition. The implemented antenna-coupled FET detector structures aim to improve the detection behavior in terms of responsivity and noise equivalent power (NEP) for CMOS based imaging applications. Since the detected THz signals by using this approach are extremely weak with limited bandwidth, the next section of this work presents a pixel-level readout chain containing a cascade of a pre-amplification and noise reduction stage based on a parametric chopper amplifier and a direct analog-to-digital conversion by means of an incremental Sigma-Delta converter. The readout circuit aims to perform a lock-in operation with modulated sources. The in-pixel readout chain provides simultaneous signal integration and noise filtering for the multi-pixel FET detector arrays and hence achieving similar sensitivity by the external lock-in amplifier. Next, based on the experimental THz characterization and measurement results of a single pixel (antenna-coupled FET detector + readout circuit), the design and implementation of a multispectral imager containing 10 x 10 THz focal plane array (FPA) as well as 50 x 50 (3T-APS) visible pixels is presented. Moreover, the readout circuit for the visible pixel is realized as a column-level correlated double sampler. All of the designed chips have been implemented and fabricated in 0.15-Âμm standard CMOS technology. The physical implementation, fabrication and electrical testing preparation are discussed.

Modern communication and space systems such as satellite communication devices, radars, SAR and radio astronomy interferometers are realized with large antenna arrays since this kind of radiating systems are able to generate radiation patterns with high directivity and resolution. In such a framework conventional arrays with uniform inter-element spacing could be not satisfactory in terms of costs and dimensions. An interesting alternative is to reduce the array elements obtaining the so called "thinned arrays". Large isophoric thinned arrays have been exploited because of their advantages in terms of weight, consumption, hardware complexity, and costs over their filled counterparts. Unfortunately, thinning large arrays reduces the control of the peak sidelobe level (PSL) and does not give automatically optimal spatial frequency coverage for correlators. First of all the state of the art methodologies used to overcome such limitations, e.g., random and algorithmic approaches, dynamic programming and stochastic optimization algorithms such as genetic algorithms, simulated annealing or particle swarm optimizers, are analyzed and described in the introduction. Successively, innovative guidelines for the synthesis of large radiating systems are proposed, and discussed in order to point out advantages and limitations. In particular, the following specific issues are addressed in this work: 1. A new class of analytical rectangular thinned arrays with low peak sidelobe level (PSL). The proposed synthesis technique exploits binary sequences derived from McFarland difference sets to design thinned layouts on a lattice of P(P+2) positions for any prime P. The pattern features of the arising massively-thinned arrangements characterized by only P(P+1) active elements are discussed and the results of an extensive numerical analysis are presented to assess advantages and limitations of the McFarland-based arrays. 2. A set of techniques is presented that is based on the exploitation of low correlation Almost Difference Sets (ADSs) sequences to design correlator arrays for radioastronomy applications. In particular three approaches are discussed with different objectives and performances. ADS-based analytical designs, GA-optimized arrangements, and PSO optimized arrays are presented and applied to the synthesis of open-ended "Y" and "Cross" array configurations to maximize the coverage u-v or to minimize the peak sidelobe level (PSL). Representative numerical results are illustrated to point out the features and performances of the proposed approaches, and to assess their effectiveness in comparison with state-of-the-art design methodologies, as well. The presented analysis indicates that the proposed approaches overcome existing PSO-based correlator arrays in terms of PSL control (e.g., >1.0dB reduction) and tracking u-v coverage (e.g., up to 2\% enhancement), also improving the speed of convergence of the synthesis process. 3. A genetic algorithm (GA)-enhanced almost difference set (ADS)-based methodology to design thinned planar arrays with low-peak sidelobe levels (PSLs). The method allows to overcome the limitations of the standard ADS approach in terms of flexibility and performance. The numerical validation, carried out in the far-field and for narrow-band signals, points out that with affordable computational efforts it is possible to design planar array arrangements that outperform standard ADS-based designs as well as standard GA design approaches.