Mongi Lahiani

Electrical modeling of inductive links for high-efficiency energy transmission

This paper presents an innovative modeling method for the mutual inductance of two magnetically coupled coils in an inductive link, ensuring efficient energy and data transmission in implantable electronic devices. An electrical model, which can be used within a circuit simulator, directly takes into account the lateral and longitudinal displacements between the external coil (transmitter) and the internal coil (receiver), thus enabling to optimize the voltage gain of the link, and opening to the design of inductive links with high power transfer capabilities and high overall efficiency.

Maximum of mutual inductance by inductive link

This paper presents inductive link between various coils or various forms to protect the reserve of unidirectional energy and from bi-directional data in the implantables electronic devices. Study will rest on the increase of the efficiency allocated by the tolerance to the lateral, longitudinal and even angular displacement between the external coil (transmitter) and the implanted coil (receiver).

Design of rectangular microstrip patch antenna

The purpose of this paper is to design a microstrip rectangular antenna in Advance Design System Momentum (ADS). The resonant frequency of antenna is 4.1GHz. The reflection coefficient is less than -10dB for a frequency range of 3.1GHz to 5.1 GHz. The proposed rectangular patch antenna has been devise using Glass Epoxy substrate (FR4) with dielectric constant (εr = 4.4), loss tangent (tan δ) equal to 0.02. This rectangular patch is excited using transmission lines of particular length and width. Various parameters, for example the gain, S parameters, directivity and efficiency of the designed rectangular antenna are obtained from ADS Momentum.

Influence of the cardiac activity on the surface impedance of a multilayer model

Biological tissues are seen as multilayer structures. We will use in this article a model with three layers: skin, fat and muscle. This structure may be related to a pattern of cascaded lines where each tissue has its own characteristic impedance, permittivity and conductivity. This structure allows us to solve the problem of the surface impedance. Each layer is similar to a line of characteristic impedance. The impedance of the first layer will be transformed as soon as one progresses to the surface. This article represents, first, a detailed study of the electrical properties of a stratified propagation medium, and secondly, a study of the variation of the surface impedance according to the cardiac activity.

Design of a pulse generator for UWB communications

The Ultra Wide Band (UWB) is a technical of radio transmission which consists of using signals whose spectrum is spread out over a broad frequency band, typically ranging from MHz to several GHz frequencies. It was at first used for radar applications then applied in telecommunication applications, thus arousing a growing interest within the academic and industrial community. The present work is concerned with a research on UWB as a new technology for radar systems. Besides, it sheds light on the design of transmission system with broad ultra band an Agilent Advanced Design System modeling tool.

Modeling of the thorax of human body at 433 MHz

Nowadays, communication networks have become indispensable in our daily lives. In the last years, new networks have been developed, such as the body wireless sensor network “BAN”. So it will be necessary to highlight the influence of the body on the radiation pattern, performance and adaptation of the antenna. To understand the interaction between electromagnetic waves and the human body, it is important to have knowledge about the physical properties of biological tissues which can be seen as multilayer structures. This will be well detailed in this paper. Each layer has its own dielectric characteristics. Those properties are represented by the relative permittivity and conductivity. So to characterize tissues, we must study its properties. Then, a study of the attenuation factor is made, based on a comparison between HFSS and ADS.

Correction applied to the propagation model of UWB wave in human biological tissue obtained by FDTD method for estimation of the wave form at the heart

This work studies the spread of a UWB pulse in biological tissue, which forms the propagation media to the electromagnetic waves to detect a heartbeat. This tissue is multiple Modeled as semi-infinite lossy and dispersive media. The study focused on the deformations at the interfaces between two successive layers. The FDTD method is an approach for solving Maxwells equations. However, we note at the interfaces, the distortion signal. This is observed in the attenuation of energy signal. In this article we try to understand the origins of these disturbances, to find a solution for these perturbations, and, to estimate the waveform by adding an adaptive mesh at the interfaces.

Design of a digital communication system based on a XBee module for biomedical applications

This article describes the prototype of the digital communication system based on the XBee module. It consists on a universal system that transmits all type of data including the medical information such as Electrocardiogram (ECG). To validate this system, we have chosen to transmit the ECG from a computer to another through the XBee modules just to evaluate the quality of the wireless communication. For this, we have performed a series of indoor and outdoor tests.

Mathematical approximation of the hyperbolic tangent

This paper presents an assimilation of the transfer function of a differential pair of MOS transistors to a hyperbolic tangent function. Also it prove, that the characteristic of transfer function of a MOS differential pair is symmetrical and that is close to the one of the bipolar transistors differential pair (It represent the transfer function of this differential pair; it describe the output signal in the form of a hyperbolic tangent of the input signal) with minor differences in our application. For this comparison, we use a MOS model transistor (0.35µm) resulting from the library of the AMS foundry and on other hand we use a perfect nonlinear model of the bipolar transistor resulting from the Agilent-ADS library.

Energy harvesting from electromagnetic radiation emissions by compact flouresent lamp

The purpose of this paper is to present a new solution to produce DC energy from electromagnetic radiation generated by compact fluorescent lamps and stored in the super capacitor bank. The proposed device is based on a magnetic coupling between flat wound induction coil and pollution generator represented in the compact florescent lamp. Most of the energy will be stored in the super capacitor and then in battery through DC/DC Up convertor. It is shown that more than 0.91W can be generated from a 20W compact fluorescent lamp. So the proposed electronic device can absorb pollution at home, protect our children from radiation, and recycle EM radiation for charging battery. Besides, we can use it for many other applications.