Wideband and UWB antennas for wireless applications. A comprehensive review

A comprehensive review concerning the geometry, the manufacturing technologies, the materials, and the numerical techniques, adopted for the analysis and design of wideband and ultrawideband (UWB) antennas for wireless applications, is presented. Planar, printed, dielectric, and wearable antennas, achievable on laminate (rigid and flexible), and textile dielectric substrates are taken into account. The performances of small, low-profile, and dielectric resonator antennas are illustrated paying particular attention to the application areas concerning portable devices (mobile phones, tablets, glasses, laptops, wearable computers, etc.) and radio base stations. This information provides a guidance to the selection of the different antenna geometries in terms of bandwidth, gain, field polarization, time-domain response, dimensions, and materials useful for their realization and integration in modern communication systems

Additively Manufactured Shape-changing RF Devices Enabled by Origami-inspired Structures

The work to be presented in this dissertation explores the possibility of implementing origami-inspired shape-changing structures into RF designs to enable continuous performance tunability as well as deployability. The research not only experimented novel structures that have unique mechanical behaviour, but also developed automated additive manufacturing (AM) fabrication process that pushes the boundary of realizable frequency from Sub-6 GHz to mm-wave. High-performance origami-inspired reconfigurable frequency selective surfaces (FSSs) and reflectarray antennas are realized for the first time at mm-wave frequencies via AM techniques. The research also investigated the idea of combining mechanical tuning and active tuning methods in a hybrid manner to realize the first truly conformal beam-forming phased array antenna that can be applied onto any arbitrary surface and can be re-calibrated with a 3D depth camera.Ph.D

Design of Bio-Inspired Multifrequency Acoustic Sensors and Metamaterial Energy Harvesting Smart Structures

Due to the limited availability and high depletion rates of nonrenewable sources of energy as well as environmental concerns, the scientific community has started to explore many alternative clean sources of energies. It is identified that civil, mechanical and Aerospace structures are always subjected to acoustic noises and vibration which could potentially be used as renewable source of energy. Roads and Industrial noise barriers are used inside industrial facilities alongside the walls, around construction pillars, nearby machinery and other equipment to separate quite work zones, protect walls, deliver extra safety and precautions while diminish sound and vibrational pressure. We hypothesized if these noise barriers/structures could serve dual purposes, while harvest energies from the filtered noises and vibrations, significant energies could be renewed. Such renewable energies could be then used for different purposes, like charging cell phones, wearable devices, powering small electronics and remote sensors etc. Additionally, due to gravity, it is natural that our heavy mechanical equipment runs, operates, walks on the ground which are covered by cosmetic materials. Such materials encounter continuously changing pressure on the surface which is otherwise waisted if not harvested. Keeping these applications in mind for walls/ barriers/ tiles, oin this dissertation, utilizing one unique physics, two different type of renewable energy harvesting technologies are proposed. While proposing the application of harvesting and noise filtering, similar physics/mechanics prevalent in cochlea of human inner ear, further motivated this dissertation to device bio-inspired acoustic bandpass sensor. The harvesting and sensing devices that are conceptualized, analytically modeled, numerically simulated via COMSOL Multiphysics software, optimized, fabricated and tested to present the proof of concept are presented below. All models are numerically 1) A novel three-dimensional piezoelectric energy harvester based on a metamaterial structure is proposed, which is capable of scavenging energy at very low frequencies (\u3c~1kHz) from multi-axial ambient vibrations. The proposed structure and its unit cell exploit the negative mass at local resonance frequencies and entraps the vibration energy as dynamic strain. The captured kinetic energy is then transformed to electric potential using three Lead Zirconate Titanate wafers, optimally embedded in the cell\u27s soft constituent. 2) In the second design, a multi-frequency vibration-based energy harvester unit cell which is inspired from the design of human inner-ear, i.e. a snail-shaped model to enhance differential shear deformation of a membrane is proposed. Next an array of the proposed cell in the form of metamaterial bricks in a wall or a metamaterial tiles on the ground (Meta-tile) are modeled and fabricated to experimentally validated the concept. A spiral snail shaped PVDF membrane is embedded inside a Polydimethylsiloxane (PDMS) matrix that entraps the kinetic energy of the vibration within its structure. Numerical and experimental studies show that the unit cell and the Meta-tiles can harvest electrical power of up to ~1.8 mW and 11 mW against a 10KΩ resistive load, respectively. 3) Concurrent to the development of electronic processing of frequencies, mechanical sensors capable of selecting, processing, filtering specific single or a distinct band of frequencies are contributing an essential role in many sciences, technologies and industrial applications. After developing the energy harvester devices, the next objective of this PhD dissertation is to present a scalable numerical model along with a fabricated proof of concept of a bio-inspired acoustic bandpass sensor with a user-defined range of frequencies. In the proposed sensor, the geometric structure of a human’s basilar membrane is adopted as the main model to capture the sonic waves with a target frequency ranges. Human’s basilar membrane in the inner ear could be investigated in two ways, a) plate type and b) beam type. Both models are numerically and experimentally validated. In the first step, a predictive mathematical model of the proposed bandpass sensor is developed based on a plate type model. Next, the dynamic behavior of beam-type basilar membrane with 100 Zinc-Oxide electrodes is modeled and numerically verified. A sensor array is fabricated with using photolithography techniques with Polyvinylidene Difluoride (PVDF) piezoelectric material as a proof-of-concept. The fabricated plate-type sensor is experimentally tested, and its effective performance is validated in the frequency range of ~3 kHz-8 kHz. Similarly, in beam model the longest electrode is near the Apex region (8 mm x 300 μm x 20 μm thick) and the shortest electrode is near the Base side of the sensor with (3 mm x 300 μm x 110 μm thick) are proposed. Eventually, the effective performances of the proposed acoustic sensors are verified using COMSOL Multiphysics Software and the functionality of the proposed sensor appeared in the frequency range of ~ 0.5 kHz near Apex and to ~ 20 kHz near base side. To run all the required experiments on the fabricated energy harvesters and acoustic sensors in this dissertation, a novel three-dimensional exciter is developed as a miscellaneous work. A high percentage of failures in sensors and devices employed in harsh industrial environments and airborne electronics is due to mechanical vibrations and shocks. Therefore, it is important to test the equipment reliability and ensure its survival in long missions in the presence of physical fluctuations. Traditional vibration testbeds employ unidirectional acoustic or mechanical excitations. However, in reality, equipment may encounter uncoupled (unidirectional) and/or coupled (multidirectional) loading conditions during operation. Hence, to systematically characterize and fully understand the proposed energy harvesters’ and acoustic sensors’ behaviors, a testbed capable of simulating a wide variety of vibration conditions is required which is designed, and fabricated. The developed testbed is an acousto electrodynamic three-dimensional (3-D) vibration exciter (AEVE 3-D), which simulates coupled and decoupled (with unpowered arms) 3-D acoustic and/or 3-D mechanical vibration environments. AEVE 3-D consists of three electromagnetic shakers (for mechanical excitation) and three loudspeakers (for acoustic excitation) as well as a main control unit that accurately calculates and sets the actuators\u27 input signals in order to generate optimal coupled and decoupled vibrations at desired frequencies. In this paper, the system\u27s architecture, its mechanical structure, and electrical components are described. In addition, to verify AEVE 3-D\u27s performance, various experiments are carried out using a 3-D piezoelectric energy harvester and a custom-made piezoelectric beam

Additive Manufactured Antennas and Novel Frequency Selective Sensors

The research work carried out and reported in this thesis focuses on the application of additive manufacturing (AM) for the development antennas and novel frequency selective surfaces structures. Various AM techniques such as direct writing (DW), material extrusion, nanoparticle conductive inks are investigated for the fabrication of antennas and FSS based sensors. This research has two parts. The first involves the development of antennas at the microwave and millimetre wave bands using AM techniques. Inkjet printing of nanoparticle silver inks on paper substrate is employed in the fabrication of antennas for an origami robotic bird. This provides an exploration on the practicability of developing foldable antennas which can be integrated on expendable robots using low-cost household inkjet printers. This is followed using Aerosol jet printing in the fabrication of fingernail wearable antennas. The antennas are developed to operate at microwave and millimetre wave bands for potential use in 5G Internet of Things (IoT) or body-centric networks. The second part of the research work involves the development of frequency selective sensors. Trenches have been incorporated on an FSS structure to produce a new concept of liquid sensor. The sensor is fabricated using standard etching techniques and then using FDM method in conjunction with nanoparticle conductive ink. Finally, a new concept displacement sensor using an FSS coupled with a retracting substrate complement is introduced. The displacement sensor is a 3D structure which is conveniently fabricated using AM techniques

Internet of Harvester Nano Things: A Future Prospects

The advancements in nanotechnology, material science, and electrical engineering have shrunk the sizes of electronic devices down to the micro/nanoscale. This brings the opportunity of developing the Internet of Nano Things (IoNT), an extension of the Internet of Things (IoT). With nanodevices, numerous new possibilities emerge in the biomedical, military fields, and industrial products. However, a continuous energy supply is needed for these devices to work. At the micro/nanoscale, batteries cannot supply this demand due to size limitations and the limited energy contained in the batteries. Internet of Harvester Nano Things (IoHNT), a concept of Energy Harvesting (EH), which converts the existing different energy sources, which otherwise would be dissipated to waste, into electrical energy via electrical generators. Sources for EH are abundant, from sunlight, sound, water, and airflow to living organisms. IoHNT methods are significant assets to ensure the proper operation of the IoNT; thus, in this review, we comprehensively investigate the most useful energy sources and IoHNT principles to power the nano/micro-scaled electronic devices with the scope of IoNT. We discuss the IoHNT principles, material selections, challenges, and state-of-the-art applications of each energy source for both in-vivo and in vitro applications. Finally, we present the latest challenges of EH along with future research directions to solve the problems regarding constructing continuous IoNT containing various self-powered nanodevices. Therefore, IoHNT represents a significant shift in nanodevice power supply, leading us towards a future where wireless technology is widespread. Hence, it will motivate researchers to envision and contribute to the advancement of the following power revolution in IoNT, providing unmatched simplicity and efficiency

Chipless RFID sensor systems for structural health monitoring

Ph. D. ThesisDefects in metallic structures such as crack and corrosion are major sources of catastrophic failures, and thus monitoring them is a crucial issue. As periodic inspection using the nondestructive testing and evaluation (NDT&E) techniques is slow, costly, limited in range, and cumbersome, novel methods for in-situ structural health monitoring (SHM) are required. Chipless radio frequency identification (RFID) is an emerging and attractive technology to implement the internet of things (IoT) based SHM. Chipless RFID sensors are not only wireless, passive, and low-cost as the chipped RFID counterpart, but also printable, durable, and allow for multi-parameter sensing. This thesis proposes the design and development of chipless RFID sensor systems for SHM, particularly for defect detection and characterization in metallic structures. Through simulation studies and experimental validations, novel metal-mountable chipless RFID sensors are demonstrated with different reader configurations and methods for feature extraction, selection, and fusion. The first contribution of this thesis is the design of a chipless RFID sensor for crack detection and characterization based on the circular microstrip patch antenna (CMPA). The sensor provides a 4-bit ID and a capability of indicating crack width and orientation simultaneously using the resonance frequency shift. The second contribution is a chipless RFID sensor designed based on the frequency selective surface (FSS) and feature fusion for corrosion characterization. The FSS-based sensor generates multiple resonance frequency features that can reveal corrosion progression, while feature fusion is applied to enhance the sensitivity and reliability of the sensor. The third contribution deals with robust detection and characterization of crack and corrosion in a realistic environment using a portable reader. A multi-resonance chipless RFID sensor is proposed along with the implementation of a portable reader using an ultra-wideband (UWB) radar module. Feature extraction and selection using principal component analysis (PCA) is employed for multi-parameter evaluation. Overall, chipless RFID sensors are small, low-profile, and can be used to quantify and characterize surface crack and corrosion undercoating. Furthermore, the multi-resonance characteristics of chipless RFID sensors are useful for integrating ID encoding and sensing functionalities, enhancing the sensor performance, as well as for performing multi-parameter analysis of defects. The demonstrated system using a portable reader shows the capability of defects characterization from a 15-cm distance. Hence, chipless RFID sensor systems have great potential to be an alternative sensing method for in-situ SHM.Indonesia Endowment Fund for Education (LPDP