Neste trabalho buscou-se propor e implementar um modelo de material capaz de prever o comportamento mecânico de estruturas em compósitos poliméricos reforçados (CPR). Inicialmente fez-se um levantamento bibliográfico sobre os modos de danificação intralaminar e falhas interlaminares bem como sobre formas de abordagem (analítica e numérica) para tratar esses problemas. Em seguida, foram apresentadas em detalhes as etapas experimentais executadas, descrevendo todo o procedimento de fabricação dos corpos-de-prova e os resultados obtidos a partir dos ensaios quase-estáticos de tração, compressão, cisalhamento e flexão. Com base nesses resultados e em informações provenientes da literatura, propõem-se alguns modelos de material que foram implementados em sub-rotinas FORTRAN. Tais modelos são posteriormente compilados em conjunto com um programa de elementos finitos (ABAQUS®) a fim de serem avaliados e terem seus parâmetros calibrados. Numa primeira fase, através de simulações computacionais dos ensaios de tração e compressão avaliou-se os modelos de material implementados. Numa segunda fase, os parâmetros foram calibrados tomando como base três estudos de caso (flexão, endentação e teste de impacto) envolvendo seqüências de empilhamento distintas. Após a simulação computacional desses estudos, apresentou-se a proposta de uma metodologia para avaliar problemas de impacto a baixa velocidade em estruturas laminadas. Conclui-se assim que o presente projeto de pesquisa traz contribuições inovadoras, mas também apresenta várias perspectivas de trabalhos futuros. / In this work, material models were proposed to predict the mechanical behavior of composite structures. First of all, it was done a study about damage intra-ply and inter-ply (delamination) on composite materials and about analytical and numerical approaches to solve problems of progressive damage on composite structures was performed. After, many specimens were manufactured and experimental tests (tensile, compression, shear and flexural tests) were carried out. Experimental results and information from literature were used to develop some material models, which were implemented using FORTRAN compiler. These material models were compiled with a commercial finite element program (ABAQUS®) in order to evaluate and calibrate parameters of the models. In the first step, computational simulations of tensile and compression test were carried out to evaluate material models implemented. In the second step, the parameters of the material models were calibrated using three case studies (flexural, indentation and impact test) with some staking sequences. After that, a methodology was proposed to evaluate impact problems on composite structures under low velocity. Therefore, this research project not only shows new contributions but also suggests many future investigations.

Le terme élastographie désigne les techniques d'imagerie dédiées à l'étude des propriétés mécaniques des tissus biologiques in vivo. Au cours de cette thèse, nous nous sommes intéressés à deux de ces techniques. La première est l'élastographie quasi-statique par ultrasons permettant de mesurer les déformations locales induites dans un tissu sous l'action d'une contrainte globale. La seconde est l'élastographie par résonance magnétique (ERM) permettant d'accéder localement à une estimation du module de cisaillement. Pour cette dernière technique, une onde de cisaillement est générée au sein du milieu puis imagée a l'aide d'une séquence IRM spécifique. Les images d'ondes acquises permettent la reconstruction du module de cisaillement local. Dans le cadre de ces travaux, une nouvelle technique d'acquisition de l'image d'onde de cisaillement a été proposée, ainsi qu'une méthode de reconstruction du module de cisaillement basée sur l'estimation locale de fréquence par rapport de filtres. Un autre axe de recherche a consisté en l'étude de l'effet d'une précontrainte appliquée à un milieu sur son module de cisaillement mesuré par ERM. Cet effet a tout d'abord été étudié sur des milieux homogènes puis avec des milieux test hétérogènes. Dans ce dernier cas, l'utilisation de l'élastographie quasi-statique par ultrasons s'avère nécessaire pour accéder à la déformation locale du milieu. Cette dernière information a été combinée avec les informations obtenues en ERM pour extraire pour chaque région d'intérêt une courbe déformation/module de cisaillement / The term elastography refers to imaging techniques dedicated to the in vivo investigation of the mechanical properties of biological tissues. During this thesis, we focused on two elastography techniques. The first one is quasi-static ultrasound elastography, able to locally estimate tissue strain induced by a global deformation of a medium. The second one is Magnetic Resonance Elastography (MRE), able to measure the local shear modulus. In MRE, a shear wave is generated within the medium and imaged using a specific MRI sequence. The resulting wave images are then processed to estimate the local shear modulus. A new acquisition scheme of the shear wave images was proposed during this thesis. A method, based on local frequency estimation, was also developed for the estimation of the local shear modulus using the properties of a ratio of filters. Another research axis was the study of the effect of a prestrain application on the measured shear modulus. This effect was first studied with homogeneous media and then with heterogeneous test objects. In this last case, the use of quasi-static ultrasound elastography was necessary to locally access to the medium strain. This information was then combined with the information obtained using MRE to extract, for each region of interest, a strain/shear modulus curve

This master’s thesis deals with creation and modification of several numerical rat’s brain models which are subsequently used in electromagnetic software CST Studio Suite 2014. The first part of the thesis is focused to insertion of exciting source to the model which depends on the used approach. These sources produce signals on the surface of the rat’s brain model which are then analysed. The experimental part of the thesis dealt with three different procedures of cooking agar jelly, which were used for creation of five plate capacitors, which subsequently served for measure electric properties of phantom. The conclusion of this master’s thesis is focused on comparison between results from simulations and experimental parts with a subsequent analysis of the deviations of results and their possible causes.

In this work is proposed the generalized powertrain of the parallel hybrid car. The powertrain is composed from the sub-models of the power sources. Each sub-model is described by the quasi-static modeling. For given routes is computed the power demand. Based on the derived power demand, three energy management systems are tested. First system is based on heuristic rules. The second one use more sophisticated control algorithms - the optimization method. Main idea is based on minimum principle, when the control algorithm tries to minimize the cost function (fuel use, emission). The last one is based on the equivalent consumption minimization strategy.

This diploma thesis deals with Formula Student Impact Attenuator design. The aim of the thesis is to select suitable material and put it to the test of deformation. From results to suggest dimensions of Impact Attenuator and then perform its test. Next aim of the thesis is to perform FEM analysis of Anti-Intrusion plate and supporting rack.

In this dissertation, we use finite element method together with other numerical techniques to study advanced electron devices. We study the radiation properties in electron waveguide structure with multi-step discontinuities and soft wall lateral confinement. Radiation mechanism and conditions are examined by numerical simulation of dispersion relations and transport properties. The study of geometry variations shows its significant impact on the radiation intensity and direction. In particular, the periodic corrugation structure exhibits strong directional radiation. This interesting feature may be useful to design a nano-scale transmitter, a communication device for future nano-scale system. Non-quasi-static effects in AC characteristics of carbon nanotube field-effect transistors are examined by solving a full time-dependent, open-boundary Schrödinger equation. The non-quasi-static characteristics, such as the finite channel charging time, and the dependence of small signal transconductance and gate capacitance on the frequency, are explored. The validity of the widely used quasi-static approximation is examined. The results show that the quasi-static approximation overestimates the transconductance and gate capacitance at high frequencies, but gives a more accurate value for the intrinsic cut-off frequency over a wide range of bias conditions. The influence of metal interconnect resistance on the performance of vertical and lateral power MOSFETs is studied. Vertical MOSFETs in a D2PAK and DirectFET package, and lateral MOSFETs in power IC and flip chip are investigated as the case studies. The impact of various layout patterns and material properties on RDS(on) will provide useful guidelines for practical vertical and lateral power MOSFETs design.

M. Tech. (Department of Mechanical Engineering, Faculty of Engineering and Technology), Vaal University of Technology. / Sisal is a vegetable fibre extracted from the leaves of Agave Sisalana. The fibre is long, bold and creamy white in colour besides being exceptionally strong. It can be used for making agricultural and parcelling twines of various kinds as well as ropes, sacks, carpet and upholstery. The primary purpose of this research was to study and evaluate the use of sisal as a reinforcing fibre in both treated and untreated forms with epoxy resin matrices. The casting process employed during the composite production was the the vacuum infusion. The effects of both the treated sisal fibre-epoxy resin composites and the untreated sisal fibre-epoxy resin composites on the tensile strength and stiffness, flexural strength and stiffness, impact toughness, shear strength, compression strength and hardness were evaluated. Finally, the occurrence of transverse matrix fracture and fibre pull-out were also studied. It was found that the quasi-static mechanical properties of both the treated sisal fibre-epoxy resin composites and the untreated sisal fibre-epoxy resin composites improved with increases in reinforcement weight fractions. Further, fibre surface treatment on the sisal fibres and the attendant increase in the interfacial bond also resulted into improved quasi-static mechanical properties of the treated sisal fibre-epoxy resin composites when compared to untreated sisal fibre-epoxy resin composites.

yes / There is an increasing need for accurate models describing the electrical behaviour of individual biological cells exposed to electromagnetic fields. In this area of solving linear problem, the most frequently used technique for computing the EM field is the Finite-Difference Time-Domain (FDTD) method. When modelling objects that are small compared with the wavelength, for example biological cells at radio frequencies, the standard Finite-Difference Time-Domain (FDTD) method requires extremely small time-step sizes, which may lead to excessive computation times. The problem can be overcome by implementing a quasi-static approximate version of FDTD, based on transferring the working frequency to a higher frequency and scaling back to the frequency of interest after the field has been computed. An approach to modeling and analysis of biological cells, incorporating the Hodgkin and Huxley membrane model, is presented here. Since the external medium of the biological cell is lossy material, a modified Berenger absorbing boundary condition is used to truncate the computation grid. Linear assemblages of cells are investigated and then Floquet periodic boundary conditions are imposed to imitate the effect of periodic replication of the assemblages. Thus, the analysis of a large structure of cells is made more computationally efficient than the modeling of the entire structure. The total fields of the simulated structures are shown to give reasonable and stable results at 900MHz, 1800MHz and 2450MHz. This method will facilitate deeper investigation of the phenomena in the interaction between EM fields and biological systems. Moreover, the nonlinear response of biological cell exposed to a 0.9GHz signal was discussed on observing the second harmonic at 1.8GHz. In this, an electrical circuit model has been proposed to calibrate the performance of nonlinear RF energy conversion inside a high quality factor resonant cavity with known nonlinear device. Meanwhile, the first and second harmonic responses of the cavity due to the loading of the cavity with the lossy material will also be demonstrated. The results from proposed mathematical model, give good indication of the input power required to detect the weakly effects of the second harmonic signal prior to perform the measurement. Hence, this proposed mathematical model will assist to determine how sensitivity of the second harmonic signal can be detected by placing the required specific input power.

Aus einkristallinem Silizium gefertigte Mikroscanner werden zunehmend in Anwendungen zur Bildprojektion, Entfernungssensorik, Spektroskopie und gezielten Strahlführung von Lasern eingesetzt, denn sie ermöglichen die Miniaturisierung und Massenfertigung optischer Systeme. Durch die statische Strahlpositionierung und zum linearen Rasterscannen in einem breiten Frequenzbereich von Null bis mehrere hundert Hertz eröffnen sogenannte quasi-statische Mikroscanner im Vergleich zu bisherigen resonant schwingenden Mikroscannern ein deutlich breiteres und flexibleres Anwendungsspektrum. Jedoch wird die Bewegung aufgrund der extrem geringen Dämpfung des Systems mit Eigenschwingungen überlagert. Daher ist die Steuerung und Regelung eine notwendige Voraussetzung für die hochdynamische und präzise Strahlführung mit quasi-statischen Mikroscannern. In dieser Arbeit werden verschiedene Steuerungs- und Regelungskonzepte für quasi-statische Mikroscanner mit elektrostatischem Kammantrieb entworfen und auf einem Echtzeitsystem mit optischer Rückführung experimentell verifiziert. Das nichtlineare mechatronische Modell wird vollständig parametrisiert und geeignete Trajektorien mit Ruckbegrenzung werden hergeleitet. Schließlich werden die Regelung des Mikroscanners mit einem Mikrocontroller durch die im Chip integrierte piezoresistive Positi-nssensorik validiert und ein 2D-Rasterscan realisiert. Als Ergebnis werden Folgerungen für den Systementwurf von quasi-statischen Mikroscannern abgeleitet.:Kurzfassung Abstract Inhaltsverzeichnis Abbildungs- und Tabellenverzeichnis Abkürzungs- und Symbolverzeichnis 1 Einleitung 1.1 Anwendungsgebiete 1.2 Antriebsprinzipien für Mikroscanner 1.3 Quasi-statische Mikroscanner des Fraunhofer IPMS 1.4 Mechatronische Modellbildung 1.4.1 Elektrostatischer Elementarwandler 1.4.2 Mechanische Beschaltung 1.4.3 Impedanzrückkopplung 2 Stand der Technik und eigene Beiträge 2.1 Steuerungs- und regelungstechnische Aspekte 2.1.1 Steuerung 2.1.2 Regelung 2.2 Präzisierung der Aufgabenstellung 2.3 Problemstellungen und eigene Beiträge 3 Modellbildung 3.1 Physikalische Modellbildung 3.1.1 Elektrisches Teilsystem 3.1.2 Mechanisches Teilsystem 3.1.3 Mechatronischer Wandler 3.2 Regelungstechnische Modellbildung 3.2.1 Kleinsignalmodell 3.2.2 Zustandsraummodell und Flachheit 3.3 Experimentelle Modellbildung 3.3.1 Bestimmung der Federsteifigkeit und der Dämpfung 3.3.2 Bestimmung der Kapazitätskennlinien 3.4 Schlussfolgerungen 4 Trajektorienentwurf 4.1 Anforderungen 4.1.1 FOURIER-Zerlegung von Dreieck- und Sägezahnfunktion 4.1.2 Überlagerung mit der Streckendynamik 4.2 Ruckbegrenzung 4.2.1 Stufentrajektorie 4.2.2 Dreieck- und Sägezahntrajektorien 4.3 Entwurf mit Regelreserve 4.3.1 Aktuationsbereich 4.3.2 Regelreserve 4.4 Schlussfolgerungen 5 Steuerungs- und Regelungsentwurf 5.1 Steuerung 5.1.1 Statische Steuerung 5.1.2 Vorfilter 5.1.3 Flachheitsbasierte Vorsteuerung 5.1.4 Simulationsergebnisse 5.1.5 Fazit 5.2 Vorauswahl geeigneter Regelungsalgorithmen 5.3 Lineare Regelung 5.3.1 Robuster PID-Regler 5.3.2 Gain-Scheduling-Regler 5.4 Nichtlineare Regelung 5.4.1 Flachheitsbasierte Regelung 5.4.2 Gleitzustandsregelung 5.4.3 Beobachterentwurf 5.4.4 Flachheitsbasierte Vorsteuerung mit Ausgangsstabilisierung 5.4.5 Fazit 5.5 Repetitive Regelung 5.5.1 Dimensionierung des Stabilitätsfilters 5.5.2 Dimensionierung des Lernfilters 5.5.3 Entwurf im linearen und nichtlinearen Regelkreis 5.6 Simulative Verifikation der Regelungsalgorithmen 5.6.1 Simulationsmodell 5.6.2 Simulationsergebnisse 5.6.3 Reglerparametrierung 5.6.4 Regelfrequenzvariation 5.6.5 Variation der Modellparameter 5.6.6 Einfluss von Messrauschen 5.7 Schlussfolgerungen 6 Experimentelle Systemverifikation und Diskussion 6.1 Messaufbau mit Echtzeitsystem 6.1.1 Messaufbau 6.1.2 Echtzeitsystem 6.1.3 Auswertung des optischen Positionsdetektors 6.2 Experimentelle Ergebnisse mit Echtzeitsystem 6.2.1 Fehlerdefinition 6.2.2 Modellverifikation 6.2.3 Ergebnisse der Steuerungsverfahren 6.2.4 Ergebnisse der Regelungsverfahren 6.3 Regelung mit Mikrocontroller 6.3.1 Mikrocontroller und Treiberelektronik 6.3.2 Integrierte piezoresistive Positionssensorik 6.3.3 Regelungsergebnisse mit Mikrocontroller 6.4 Zusammenfassende Diskussion der Ergebnisse 7 Folgerungen für den Systementwurf 7.1 Entwurfsraum 7.1.1 Dynamische Deformation 7.1.2 Stabilitätsspannung 7.1.3 Trajektorienentwurfsraum 7.2 Einsatz der Steuerung und Regelung 7.3 Varianten der Kammanordnung 8 Zusammenfassung 8.1 Erreichte Ziele 8.2 Ausblick 8.3 Abschlussfazit Literaturverzeichnis Publikationen Anhang A Modellbildung und Simulation A.1 Elemente der strukturierten Analyse A.2 Grundlagen der Elektrostatik A.3 Ausführlicher Lagrange-Formalismus A.3.1 Q-Koordinaten A.3.2 PSI-Koordinaten A.4 Kapazitätskennlinien A.5 Impedanzrückkopplung A.6 Mikroscannerparameter A.7 Regelparameter der Simulation A.8 Stabilitätsnachweis der flachheitsbasierter Vorsteuerung mit Ausgangsstabilisierung Anhang B Experimentelle Verifikation B.1 Regelparameter der Messung B.2 Spannungs- und Winkelbeschleunigungsverläufe B.3 Ergebnisse der repetitiven Regelung mit Sägezahntrajektorie B.4 Impedanzmessung der Kammkapazitäten B.5 Geräteliste Thesen / Monocrystalline silicon microscanners are increasingly used in applications for image projection, distance sensors, spectroscopy and laser beam control, because they allow the miniaturization and mass production of optical systems. With static beam positioning and linear raster scanning abilities in a wide range of zero to several hundred hertz the so-called quasi-static microscanners offer a much broader and more flexible range of applications compared to common resonantly oscillating microscanners. However, the movement is superimposed with natural oscillations due to the extremely low system damping. Therefore, an open-loop and closed-loop control is necessary for highly dynamic and accurate beam control with quasi-static microscanners. In this thesis different concepts for open-loop and closed-loop control of quasi-static microscanners with electrostatic comb drives are designed and verified experimentally on a real-time system with optical feedback. The nonlinear mechatronic model becomes completely parameterized and suitable trajectories with jerk limitation are derived. The control of the microscanner on a microcontroller with feedback by the on-chip inte-rated piezoresistive position sensors is validated realizing a 2D raster scan. As a result, conclusions for the system design are derived for quasi-static microscanners.:Kurzfassung Abstract Inhaltsverzeichnis Abbildungs- und Tabellenverzeichnis Abkürzungs- und Symbolverzeichnis 1 Einleitung 1.1 Anwendungsgebiete 1.2 Antriebsprinzipien für Mikroscanner 1.3 Quasi-statische Mikroscanner des Fraunhofer IPMS 1.4 Mechatronische Modellbildung 1.4.1 Elektrostatischer Elementarwandler 1.4.2 Mechanische Beschaltung 1.4.3 Impedanzrückkopplung 2 Stand der Technik und eigene Beiträge 2.1 Steuerungs- und regelungstechnische Aspekte 2.1.1 Steuerung 2.1.2 Regelung 2.2 Präzisierung der Aufgabenstellung 2.3 Problemstellungen und eigene Beiträge 3 Modellbildung 3.1 Physikalische Modellbildung 3.1.1 Elektrisches Teilsystem 3.1.2 Mechanisches Teilsystem 3.1.3 Mechatronischer Wandler 3.2 Regelungstechnische Modellbildung 3.2.1 Kleinsignalmodell 3.2.2 Zustandsraummodell und Flachheit 3.3 Experimentelle Modellbildung 3.3.1 Bestimmung der Federsteifigkeit und der Dämpfung 3.3.2 Bestimmung der Kapazitätskennlinien 3.4 Schlussfolgerungen 4 Trajektorienentwurf 4.1 Anforderungen 4.1.1 FOURIER-Zerlegung von Dreieck- und Sägezahnfunktion 4.1.2 Überlagerung mit der Streckendynamik 4.2 Ruckbegrenzung 4.2.1 Stufentrajektorie 4.2.2 Dreieck- und Sägezahntrajektorien 4.3 Entwurf mit Regelreserve 4.3.1 Aktuationsbereich 4.3.2 Regelreserve 4.4 Schlussfolgerungen 5 Steuerungs- und Regelungsentwurf 5.1 Steuerung 5.1.1 Statische Steuerung 5.1.2 Vorfilter 5.1.3 Flachheitsbasierte Vorsteuerung 5.1.4 Simulationsergebnisse 5.1.5 Fazit 5.2 Vorauswahl geeigneter Regelungsalgorithmen 5.3 Lineare Regelung 5.3.1 Robuster PID-Regler 5.3.2 Gain-Scheduling-Regler 5.4 Nichtlineare Regelung 5.4.1 Flachheitsbasierte Regelung 5.4.2 Gleitzustandsregelung 5.4.3 Beobachterentwurf 5.4.4 Flachheitsbasierte Vorsteuerung mit Ausgangsstabilisierung 5.4.5 Fazit 5.5 Repetitive Regelung 5.5.1 Dimensionierung des Stabilitätsfilters 5.5.2 Dimensionierung des Lernfilters 5.5.3 Entwurf im linearen und nichtlinearen Regelkreis 5.6 Simulative Verifikation der Regelungsalgorithmen 5.6.1 Simulationsmodell 5.6.2 Simulationsergebnisse 5.6.3 Reglerparametrierung 5.6.4 Regelfrequenzvariation 5.6.5 Variation der Modellparameter 5.6.6 Einfluss von Messrauschen 5.7 Schlussfolgerungen 6 Experimentelle Systemverifikation und Diskussion 6.1 Messaufbau mit Echtzeitsystem 6.1.1 Messaufbau 6.1.2 Echtzeitsystem 6.1.3 Auswertung des optischen Positionsdetektors 6.2 Experimentelle Ergebnisse mit Echtzeitsystem 6.2.1 Fehlerdefinition 6.2.2 Modellverifikation 6.2.3 Ergebnisse der Steuerungsverfahren 6.2.4 Ergebnisse der Regelungsverfahren 6.3 Regelung mit Mikrocontroller 6.3.1 Mikrocontroller und Treiberelektronik 6.3.2 Integrierte piezoresistive Positionssensorik 6.3.3 Regelungsergebnisse mit Mikrocontroller 6.4 Zusammenfassende Diskussion der Ergebnisse 7 Folgerungen für den Systementwurf 7.1 Entwurfsraum 7.1.1 Dynamische Deformation 7.1.2 Stabilitätsspannung 7.1.3 Trajektorienentwurfsraum 7.2 Einsatz der Steuerung und Regelung 7.3 Varianten der Kammanordnung 8 Zusammenfassung 8.1 Erreichte Ziele 8.2 Ausblick 8.3 Abschlussfazit Literaturverzeichnis Publikationen Anhang A Modellbildung und Simulation A.1 Elemente der strukturierten Analyse A.2 Grundlagen der Elektrostatik A.3 Ausführlicher Lagrange-Formalismus A.3.1 Q-Koordinaten A.3.2 PSI-Koordinaten A.4 Kapazitätskennlinien A.5 Impedanzrückkopplung A.6 Mikroscannerparameter A.7 Regelparameter der Simulation A.8 Stabilitätsnachweis der flachheitsbasierter Vorsteuerung mit Ausgangsstabilisierung Anhang B Experimentelle Verifikation B.1 Regelparameter der Messung B.2 Spannungs- und Winkelbeschleunigungsverläufe B.3 Ergebnisse der repetitiven Regelung mit Sägezahntrajektorie B.4 Impedanzmessung der Kammkapazitäten B.5 Geräteliste Thesen

The main objective of this research is to model and analyse complex electromagnetic problems by means of a new hybridised computational technique combining the frequency domain Method of Moments (MoM), Finite-Difference Time-Domain (FDTD) method and a subgridded Finite-Difference Time-Domain (SGFDTD) method. This facilitates a significant advance in the ability to predict electromagnetic absorption in inhomogeneous, anisotropic and lossy dielectric materials irradiated by geometrically intricate sources. The Method of Moments modelling employed a two-dimensional electric surface patch integral formulation solved by independent linear basis function methods in the circumferential and axial directions of the antenna wires. A similar orthogonal basis function is used on the end surface and appropriate attachments with the wire surface are employed to satisfy the requirements of current continuity. The surface current distributions on structures which may include closely spaced parallel wires, such as dipoles, loops and helical antennas are computed. The results are found to be stable and showed good agreement with less comprehensive earlier work by others. The work also investigated the interaction between overhead high voltage transmission lines and underground utility pipelines using the FDTD technique for the whole structure, combined with a subgridding method at points of interest, particularly the pipeline. The induced fields above the pipeline are investigated and analysed. FDTD is based on the solution of Maxwell¿s equations in differential form. It is very useful for modelling complex, inhomogeneous structures. Problems arise when open-region geometries are modelled. However, the Perfectly Matched Layer (PML) concept has been employed to circumvent this difficulty. The establishment of edge elements has greatly improved the performance of this method and the computational burden due to huge numbers of time steps, in the order of tens of millions, has been eased to tens of thousands by employing quasi-static methods. This thesis also illustrates the principle of the equivalent surface boundary employed close to the antenna for MoM-FDTD-SGFDTD hybridisation. It depicts the advantage of using hybrid techniques due to their ability to analyse a system of multiple discrete regions by employing the principle of equivalent sources to excite the coupling surfaces. The method has been applied for modelling human body interaction with a short range RFID antenna to investigate and analyse the near field and far field radiation pattern for which the cumulative distribution function of antenna radiation efficiency is presented. The field distributions of the simulated structures show reasonable and stable results at 900 MHz. This method facilitates deeper investigation of the phenomena in the interaction between electromagnetic fields and human tissues. / Ministry of Higher Education Malaysia and Universiti Tun Hussein Onn Malaysia (UTHM)