Underwater wireless sensor network communication using electromagnetic waves at resonance frequency 2.4 GHz

A co mprehensive study of electromagnetic waves underground propagation for a wireless sensor network is introduced in this paper. A mathemat ical model for path loss due to attenuation of electro magnetic waves propagating in different types of soil is given. Reflection fro m the air-soil interface as a function of distance between sensors and soil depth is also introduced. Three different types of soil, sandy, loamy and magnetite soil are studied. A high gain antenna is required to overcome the high value of path loss. A printed microstrip circular antenna is very common antenna used for underground wireless communication applications. A high gain microstrip circular antenna is designed and simulated using FEKO software. The antenna performance parameters studied in this paper are return loss, voltage standing wave ratio, input impedance and gain.

In this thesis, we use integral equation methods to study the scattering of timeharmonic electromagnetic plane waves by biperiodic multilayered structures. Here, such structures are modeled by vertically arranging finitely many non-self-intersecting polyhedral Lipschitz interfaces. We distinguish single profile scatterers and scatterers composed of at least two surfaces. The electromagnetic scattering problem, which arises from the presence of obstacles of the first type, serves as a basic model that we reuse in the multilayered case. By treating it with a combined potential ansatz, we obtain an equivalent new periodic singular integral equation with Fredholm index zero. The Fredholmness is verified by Garding inequalities. This property is crucial for proving one of the main results of our analysis in the single interface setting: an existence theorem for the derived integral equation under certain assumptions on the electromagnetic material parameters. The second central result, a uniqueness theorem, is proven by a variational argumentation and again depends on the values of the electromagnetic material parameters. In the main part of this thesis, we then extend the considered obstacles to “real” multilayered obstacles consisting of at least two grating interfaces. For these, we propose two recursive integral equation algorithms to determine the generated reflected and transmitted waves. On the one hand, the recursive scattering matrix method and, on the other hand, a recursive algorithm based on the transmission conditions across the interfaces of the multilayered structure. In addition to their accurate derivation, new existence and uniqueness results, depending on the electromagnetic properties of the considered obstacle, are presented for each algorithm. Their proofs partially exploit the insights originating from the treatment of the single interface model problem. Our analytical investigation is intended to provide a basis for new efficient numerical implementations of the biperiodic multilayered electromagnetic scattering problem.

The work is to design a 2x2 circular microstrip patch antenna array resonating at 2.4GHz and it is simulated for Wireless Sensor Network (WSN) applications by using HFSS tool. Circular patch antenna array is designed by depositing circular patches on FR-4 Epoxy substrate and is fed using microstrip feed lines. Fabricated antenna resonates at 2.391GHz. Antenna parameters such as Gain, return loss, Voltage Standing Wave Ratio (VSWR), Directivity, Reflection coefficient and radiation pattern are analyzed. 2x2 circular microstrip patch antenna produces more gain and less return loss compared to 2x2 rectangular microstrip patch antenna. The compact size and higher directivity compared to rectangular array makes it more relatively useful for WSN applications.

Electromagnetic (EM) wave–based underwater communication has emerged as a promising alternative for short-range and low-latency applications where acoustic and optical techniques face inherent limitations. However, the propagation behaviour of EM waves in seawater is strongly influenced by environmental factors such as frequency, salinity, depth, and medium stratification, which significantly constrain system performance. In this study, a comprehensive simulation-based analysis is carried out to investigate the behavior of electromagnetic waves in underwater environments under varying environmental conditions. A MATLAB-based numerical framework is developed to evaluate key propagation characteristics, including attenuation, path loss, penetration depth, phase delay, and the effects of layered seawater models, over a frequency range of 10 kHz to 100 MHz. Based on the obtained results, two practical design-oriented outcomes are derived: a frequency– distance feasibility map that delineates operational and non-operational regions for underwater EM communication, and a critical frequency threshold that defines the maximum usable frequency as a function of seawater salinity. The results reveal that attenuation increases sharply with frequency and salinity, layered seawater structures introduce additional propagation losses, and feasible communication ranges rapidly shrink at higher frequencies. The proposed analysis and derived feasibility metrics provide valuable insights and practical guidelines for the design and optimization of underwater electromagnetic communication systems under realistic environmental conditions.

In 2016, there were 317 serious water pollution incidents in the UK, with 78,000 locations where businesses discharge controlled quantities of pollutants into rivers; therefore, continuous monitoring is vital. Since 1998, the environment agency has taken over 50 million water samples for water quality monitoring. The Internet of Things has grown phenomenally in recent years, reaching all aspects of our lives, many of these connected devices use wireless sensor networks to relay data to internet-connected nodes, where data can be processed, analyzed and consumed. However, Underwater wireless communications rely mainly on alternative communication methods such as optical and acoustic, with radio frequencies being an under-exploited method. This research presents real world results conducted in the Leeds and Liverpool Canal for the novel use of the 433 MHz radio frequency combined with a bowtie antenna in underwater communications in raw water, achieving distances of 7 m at 1.2 kbps and 5 m at 25 kbps.

Single molecule detection and fluorescence correlation spectroscopy on surfaces

Non-conventional media comprising of underground and underwater environment use Wireless Sensor Networks (WSNs). These are used for monitoring, intrusion detection, exploration and sensing. Electromagnetic communication in nonconventional media characterizes high path loss and thus can’t be realized practically. Also, apart from high path loss it experiences ever changing channel behaviour due to soil type, moisture and depth of burial. Magnetic induction (MI)-based communication, a recently explored technique for non-conventional media, addresses the two main considerations for designing cluster-based communication protocols for wireless sensor networks: Lifetime of the network and its efficiency in energy parameter. The goal of this paper is to infer the all out total energy utilization for the proposed cooperative communication methodology, where in the quantity of nodes that take an interest in the cluster to cluster cooperative transmission is an arbitrary variable, whose esteem relies upon the intra-cluster channel and noise.

The underwater scattering channel for line-of-sight (LOS) underwater optical wireless communications in the transmission window (wavelength of 400nm–600nm) is modeled by a ray tracing technique. The inherent seawater optical properties, the scattering and absorption of the suspending particles, are represented by one single parameter—chlorophyll concentration (CC). Path losses for different waters and different ranges are simulated. The influences of some system parameters, such as beam divergence, field of view, and misalignment, to the link path loss are studied. The communication bit-error-rate performance is evaluated based on simulated path losses.

The Earth is a water planet, two-thirds of which is covered by water. With the rapid developments in technology, underwater communications has become a fast growing field, with broad applications in commercial and military water based systems. The need for underwater wireless communications exists in applications such as remote control in the off-shore oil industry, pollution monitoring in environmental systems, collection of scientific data from ocean-bottom stations, disaster detection and early warning, national security and defense (intrusion detection and underwater surveillance), as well as new resource discovery. Thus, the research of new underwater wireless communication techniques has played the most important role in the exploration of oceans and other aquatic environments. In contrast with terrestrial wireless radio communications, the communication channels in underwater wireless networks can be seriously affected by the marine environment, by noise, and by limited bandwidth and power resources, and by the harsh underwater ambient conditions. Hence, the underwater communication channel often exhibits severe attenuation, multipath effect, frequency dispersion, and constrained bandwidth and power resources, etc., which turn the underwater communication channel into one of the most complex and harsh wireless channels in nature. When facing these unique conditions in diverse underwater applications, many new challenges, which were not encountered in terrestrial wireless communications, are emerging in underwater acoustic, optical, and RF communications for future underwater wireless networks. Of these challenges, acoustic and optical are the most compelling, and somewhat complementary, owing to the potential for longer range and high bandwidth networked communications in sizeand power-constrained modems and unmanned systems.

Introduction Generalized Transport Phenomena Approach to Problem Analysis General Content Conservation Laws and Field Equations Concentrations, Velocities, and Fluxes Thermodynamics of Purely Viscous Fluid Mixtures Conservation of Mass for a One-Component System Conservation of Mass for a Mixture Modification of Field Equations for Mass Transfer Conservation of Linear Momentum for One-Component Systems Conservation of Linear Momentum for a Mixture Conservation of Moment of Momentum for One-Component Systems Conservation of Moment of Momentum for a Mixture Strategies for the Solution of Mass Transfer Problems Boundary Conditions Definitions Jump Balances for Mass Conservation Jump Balances for Linear Momentum Conservation Postulated Boundary Conditions at Phase Interfaces Boundary Conditions in the Absence of Mass Transfer Utilization of Jump Balances Additional Comments on Boundary Conditions Boundary Conditions and Uniqueness of Solutions Constitutive Equations Constitutive Principles First-Order Theory for Binary Systems Combined Field and Constitutive Equations for First-Order Binary Theory First-Order Theory for Ternary Systems Special Second-Order Theory for Binary Systems Viscoelastic Effects in Flow and Diffusion Validity of Constitutive Equations Parameters in Constitutive Equations General Approach in Parameter Determination Diffusion in Polymer-Solvent Mixtures Diffusion in Infinitely Dilute Polymer Solutions Diffusion in Dilute Polymer Solutions Diffusion in Concentrated Polymer Solutions - Free-Volume Theory for Self-Diffusion Diffusion in Concentrated Polymer Solutions - Mutual Diffusion Process Diffusion in Crosslinked Polymers Additional Properties of Diffusion Coefficients Special Behaviors of Polymer-Penetrant Systems Volumetric Behavior of Polymer-Penetrant Systems Sorption Behavior of Polymer-Penetrant Systems Antiplasticization Nonequilibrium at Polymer-Penetrant Interfaces Mathematical Apparatus Basic Definitions Classification of Second-Order Partial Differential Equations Specification of Boundary Conditions Sturm-Liouville Theory Series and Integral Representations of Functions Solution Methods for Partial Differential Equations Separation of Variables Method Separation of Variables Solutions Integral Transforms Similarity Transformations Green's Functions for Ordinary Differential Equations Green's Functions for Elliptic Equations Green's Functions for Parabolic Equations Perturbation Solutions Weighted Residual Method Solution Strategy for Mass Transfer Problems Proposed Solution Methods Induced Convection Solutions of a General Set of Mass Transfer Problems Mixing of Two Ideal Gases Steady Evaporation of a Liquid in a Tube Unsteady-State Evaporation Analysis of Free Diffusion Experiments Dissolution of a Rubbery Polymer Bubble Growth from Zero Initial Size Stability Behavior and Negative Concentrations in Ternary Systems Analysis of Impurity Migration in Plastic Containers Efficiency of Green's Function Solution Method Mass Transfer in Tube Flow Time-Dependent Interfacial Resistance Laminar Liquid Jet Diffusion Analysis Analysis of the Diaphragm Cell Dissolved Organic Carbon Removal from Marine Aquariums Unsteady Diffusion in a Block Copolymer Drying of Solvent-Coated Polymer Films Flow and Diffusion Past a Flat Plate with Solid Dissolution Gas Absorption in Vertical Laminar Liquid Jet Utilization of Polymers in Drug Delivery Gas Absorption and Diffusion into a Falling Liquid Film Perturbation Solutions of Mass Transfer Moving Boundary Problems Dissolution of a Plane Surface of a Pure Gas Phase Bubble Dissolution Singular Perturbations in Moving Boundary Problems Dropping Mercury Electrode Sorption in Thin Films Numerical Analysis of Mass Transfer Moving Boundary Problems Diffusion and Reaction Design of a Tubular Polymerization Reactor Transport Effects in Low-Pressure CVD Reactors Solution of Reaction Problems with First-Order Reactions Plug Flow Reactors with Variable Mass Density Bubble Dissolution and Chemical Reaction Danckwerts Boundary Conditions for Chemical Reactors Transport in Nonporous Membranes Assumptions Used in the Theory for Membrane Transport Steady Mass Transport in Binary Membranes Steady Mass Transport in Ternary Membranes Unsteady Mass Transport in Binary Membranes Phase Inversion Process for Forming Asymmetric Membranes Pressure Effects in Membranes Analysis of Sorption and Desorption Derivation of a Short-Time Solution Form for Sorption in Thin Films Sorption to a Film from a Pure Fluid of Finite Volume A General Analysis of Sorption in Thin Films Analysis of Step-Change Sorption Experiments Integral Sorption in Glassy Polymers Integral Sorption in Rubbery Polymers Oscillatory Diffusion and Diffusion Waves Dispersion and Chromatography Formulation of Taylor Dispersion Problem Dispersion in Laminar Tube Flow for Low Peclet Numbers Dispersion in Laminar Tube Flow for Long Times Dispersion in Laminar Tube Flow for Short Times Analysis of an Inverse Gas Chromatography Experiment Effects of Pressure Gradients on Diffusion: Wave Behavior and Sedimentation Wave Propagation in Binary Fluid Mixtures Hyperbolic Waves Dispersive Waves Time Effects for Parabolic and Hyperbolic Equations Sedimentation Equilibrium Viscoelastic Diffusion Experimental Results for Sorption Experiments Viscoelastic Effects in Step-Change Sorption Experiments Slow Bubble Dissolution in a Viscoelastic Fluid Transport with Moving Reference Frames Relationships Between Fixed and Moving Reference Frames Field Equations in Moving Reference Frames Steady Diffusion in an Ultracentrifuge Material Time Derivative Operators Frame Indifference of Material Time Derivatives Frame Indifference of Velocity Gradient Tensor Rheological Implications Appendix: Vector and Tensor Notation General Notation Conventions Vectors Tensors Results for Curvilinear Coordinates Material and Spatial Representations Reynolds' Transport Theorem

There is a speedy development withinside the place of broadband wi-fi communications as the global call for in elevating for large bandwidth and extra mobility. The speedy increase withinside the previous few a long time withinside the WAN's and LAN's is particularly because of growing improvement in excessive potential and occasional loss optical fiber. But, the main downside in optical fiber cable communique is that optical fiber receives broken in a long-haul installation. Thus, underwater communication has paved the way for overcoming this disadvantagefor programs of underwater statement and sea monitoring, the importance of underwater wi-fi optical communication has expanded. Attenuation and fading of light propagation, as well as impairment in the performance of underwater wireless optical communications, are caused by elements such as underwater absorption, scattering, and turbulence (UWOC). UWOC is a short-range wireless communication system that allows for greater data throughput than classic acoustic communication systems while using less power and posing fewer computing problems. The main challenge for underwater wireless communication, on the other hand, is from the fundamental properties of ocean or sea water. Understanding the feasibility and minimising the BER, as well as boosting the reliability of high data rate underwater communication lines, is the main topic of this paper. This study's purpose is to conduct underwater optical communication research while also producing new ideas to aid in the development of future underwater communication systems.

We study wireless sensor network (WSN) node placement in an environment where RF signal losses vary with position. This reflects real–world outdoor environments where vegetation and topography cause nonuniform path loss. Many techniques that solve for a variety of objective functions subject to various constraints have previously been proposed for node placement. However, many of these methods make simplifying assumptions such as all nodes having the same transmission range. Our goal is to take the insights and approaches of this previous ork and extend it to real–world environments. The present work assumes we have a map that quantifies the path loss behaviour of the real environment. Based on this map, and a path loss model that accounts for spatial variations in the path loss exponent, we propose a node placement algorithm for two–tiered WSNs that maximises the area covered by a specified number of relay nodes and sensor nodes.

This paper discusses the study of antenna development for partial discharge measurement, which has been conducted in the Laboratory of Voltage and High Current, School of Electrical Engineering and Informatics, Bandung Institute of Technology. This paper was created to find out the most effective shape of antenna as a partial discharge detection sensor. In the design of the antenna, there are simulation antenna, print the antenna on the PCB, and experiments using VNA-Vector Network Analyzer. In the simulation of the antenna, the application used is Ansoft HFSS. In the design, there are substrates, antenna patches, and ground with thickness and materials that are adjusted to the needs of each antenna. After simulating the antenna on Ansoft, then the antenna is printed on the PCB, for further experiments using VNA. The results of simulations as well as from experiments are compared. In antenna design, there are antenna parameters that need to be considered, including bandwidth, voltage standing wave ratio (VSWR), and return loss. From the antenna experiments that have been done in the laboratory, the most effective antenna is obtained as a sensor. It is found that the bowtie antenna with modifications at the end, the dipole antenna with the stub, and the Hilbert 3rd order fractal antenna, are the best antenna of all antennas.

In this study, bowtie antenna is designed for Ultra-Wide Band (UWB) communication applications, and radiation characteristics of the antenna in these systems are investigated by observing the behavior of parameters such as radiation pattern, return loss (S11), and voltage standing wave ratio (VSWR). Additionally, in order to improve antenna performance in the UWB frequency range, parameters such as flare angle, substrate thickness and relative dielectric constant are changed to obtain antenna structure with the best performance. CST Microwave Studio is used for the design and modeling of the antenna.

Height of the dielectric substrate material for a microstrip patch antenna is utterly important in terms of controlling bandwidth as well as surface wave. In this paper we have presented a comparative study of effect of height in the performance parameters of Rectangular Shaped Microstrip Patch antenna. The antennas were simulated for purpose of the application of wireless LAN for resonance frequency 2.45GHz. Five antennas with different heights were designed using same dielectric substrate material with relative permittivity of 2.84 for the analysis of their performances. Coaxial Probe-feed methods are used for feeding techniques. This paper along with the comparison of performance parameters like VSWR, Reflection coefficient, Bandwidth, Impedance, Mismatch loss, Directivity, Gain and Field, also presents the effect of substrate height in design parameters like width, length, feed point location, ground dimension for each patch antenna. This study was carried out by using FEKO, Electromagnetic solver software which uses Method of Moments (MoM) technique.