Feasibility and Security Analysis of Wideband Ultrasonic Radio for Smart Home Applications

Smart home Internet-of-Things (IoT) accompanied by smart home apps has witnessed tremendous growth in the past few years. Yet, the security and privacy of the smart home IoT devices and apps have raised serious concerns, as they are getting increasingly complicated each day, expected to store and exchange extremely sensitive personal data, always on and connected, and commonly exposed to any users in a sensitive environment. Nowadays wireless smart home IoT devices rely on electromagnetic wave-based radio-frequency (RF) technology to establish fast and reliable quality network connections. However, RF has its limitations that can negatively affect the smart home user experience and even cause serious security issue, such as crowded spectrum resources and RF waves leakage. To overcome those limitations, people have to use technology with sophisticated time and frequency division management and rely on the assumptions that the attackers have limited computational power. In this thesis we propose URadio, a wideband ultrasonic communication system, using electrostatic ultrasonic transducers. We design and develop two different types of transducer membranes using two types of extremely thin materials, Aluminized Mylar Film (AMF) and reduced Graphene Oxide (rGO), for assembling transducers, which achieve at least 45 times more bandwidth than commercial transducers. Equipped with the new wideband transducers, an OFDM communication system is designed to better utilize the available 600 kHz wide bandwidth. Our experiments show that URadio can achieve an unprecedentedly 4.8 Mbps data rate with a communication range of 17 cm. The attainable communication range is increased to 31 cm and 35 cm with data rates of 1.2 Mbps and 0.6 Mbps using QPSK and BPSK, respectively. Although the current wideband system only supports short-range communication, it is expected to extend the transmission range with better acoustic engineering. Also, by conducting experiments to measure the ultrasonic adversaries\u27 eavesdropping and jamming performance, we prove that our system is physically secure even when exchanging plaintext data. Adviser: Qiben Ya

Graphene MEMS capacitive microphone: highlight and future perspective

MEMS microphone is widely used in the electronic product nowadays because of its tiny size body, low power consumption and performance consistency over time and temperature. This paper highlights on the MEMS capacitive microphone and future perspective. This paper discusses the working principle of capacitive-based MEMS microphone and some of the important performance parameter that must be considered for the MEMS microphone. Recent MEMS microphone technology incorporates graphene as the microphone membrane. Finally, we discuss the future prospect and the possibility for graphene usage as the membrane for MEMS microphone

Graphene and Related Materials for the Internet of Bio-Nano Things

Internet of Bio-Nano Things (IoBNT) is a transformative communication framework, characterized by heterogeneous networks comprising both biological entities and artificial micro/nano-scale devices, so-called Bio-Nano Things (BNTs), interfaced with conventional communication networks for enabling innovative biomedical and environmental applications. Realizing the potential of IoBNT requires the development of new and unconventional communication technologies, such as molecular communications, as well as the corresponding transceivers, bio-cyber interfacing technologies connecting the biochemical domain of IoBNT to the electromagnetic domain of conventional networks, and miniaturized energy harvesting and storage components for the continuous power supply to BNTs. Graphene and related materials (GRMs) exhibit exceptional electrical, optical, biochemical, and mechanical properties, rendering them ideal candidates for addressing the challenges posed by IoBNT. This perspective article highlights recent advancements in GRM-based device technologies that are promising for implementing the core components of IoBNT. By identifying the unique opportunities afforded by GRMs and aligning them with the practical challenges associated with IoBNT, particularly in the materials domain, our aim is to accelerate the transition of envisaged IoBNT applications from theoretical concepts to practical implementations, while also uncovering new application areas for GRMs

A comprehensive review on photoacoustic-based devices for biomedical applications

The photoacoustic effect is an emerging technology that has sparked significant interest in the research field since an acoustic wave can be produced simply by the incidence of light on a material or tissue. This phenomenon has been extensively investigated, not only to perform photoacoustic imaging but also to develop highly miniaturized ultrasound probes that can provide biologically meaningful information. Therefore, this review aims to outline the materials and their fabrication process that can be employed as photoacoustic targets, both biological and non-biological, and report the main components’ features to achieve a certain performance. When designing a device, it is of utmost importance to model it at an early stage for a deeper understanding and to ease the optimization process. As such, throughout this article, the different methods already implemented to model the photoacoustic effect are introduced, as well as the advantages and drawbacks inherent in each approach. However, some remaining challenges are still faced when developing such a system regarding its fabrication, modeling, and characterization, which are also discussed.This work was supported by Fundação para a Ciência e Tecnologia national funds, under the national support to R&D units grant, through the reference project UIDB/04436/2020 and UIDP/04436/2020

Intra-Body Communications for Nervous System Applications: Current Technologies and Future Directions

The Internet of Medical Things (IoMT) paradigm will enable next generation healthcare by enhancing human abilities, supporting continuous body monitoring and restoring lost physiological functions due to serious impairments. This paper presents intra-body communication solutions that interconnect implantable devices for application to the nervous system, challenging the specific features of the complex intra-body scenario. The presented approaches include both speculative and implementative methods, ranging from neural signal transmission to testbeds, to be applied to specific neural diseases therapies. Also future directions in this research area are considered to overcome the existing technical challenges mainly associated with miniaturization, power supply, and multi-scale communications.Comment: https://www.sciencedirect.com/science/article/pii/S138912862300163

Nano-Communication for Biomedical Applications: A Review on the State-of-the-Art From Physical Layers to Novel Networking Concepts

We review EM modeling of the human body, which is essential for in vivo wireless communication channel characterization; discuss EM wave propagation through human tissues; present the choice of operational frequencies based on current standards and examine their effects on communication system performance; discuss the challenges of in vivo antenna design, as the antenna is generally considered to be an integral part of the in vivo channel; review the propagation models for the in vivo wireless communication channel and discuss the main differences relative to the ex vivo channel; and address several open research problems and future research directions

The Transport of Acoustic Energy at Two-Dimensional Material Interfaces

The control of vibrational energy within solids is a fundamental engineering challenge with numerous technological applications. While the control of electrons and photons has revolutionized computation and communication, the control of phonons, the quantized particle of vibrational energy, has been far less successful. Acoustic energy is a form of vibrational energy that involves coherent excitations of phonons to form larger elastic waves. It is this coherence that allows it to be a valuable engineering tool for applications in imaging, frequency/time control, and structural monitoring. Traditional methods of reflecting acoustic energy involve interfacing different phases of matter to reflect via an impedance mismatch, like air gaps and foams. The problem that this thesis addresses is that these methods are not scalable to extreme or nanoscale environments. The objective of this thesis is to demonstrate methods of reflecting acoustic energy by constructing solids with different types of chemical interactions, not by interfacing solids with different phases of matter. We investigate the transport of acoustic energy at the interface of two-dimensional materials. Two-dimensional materials are crystalline layers of atoms that interface with other materials via a weak van der Waals interaction. Our investigation applies both computational and experimental methods. The computational methods blend super-wavelength continuum models with sub-wavelength molecular dynamics simulations. Treating the interface as a thin plate coupled to a bulk elastic material by springs, we predict that the weak van der Waals interaction should produce a pressure-release boundary condition that reflects broad acoustic energy from infrasound to hypersound. These predictions are verified using pitch-catch experiments at 1 MHz in a water tank. The results of these experiments demonstrate a nearly three-decibel attenuation from one 2D layer. When normalized to the atomic thickness of the layer, this system provides orders of magnitude better isolation than foams, rubbers, or metasurfaces