- Eklemek veya çıkarmak istediğiniz kriterleriniz için 'Dahil' / 'Hariç' seçeneğini kullanabilirsiniz. Sorgu satırları birbirine 'VE' bağlacı ile bağlıdır. - İptal tuşuna basarak normal aramaya dönebilirsiniz.
SADOU, Hakim | HACIB, Tarik | AÇIKGÖZ, Hulusi | LE BIHAN, Yan | MEYER, Olivier | MEKIDECHE, Mohamed Rachid
Purpose: The principle of microwave characterization of dielectric materials using open-ended coaxial line probe is to link the dielectric properties of the sample under test to the measurements of the probe admittance (Y(f) = G(f)+ jB(f)). The purpose of this paper is to develop an alternative inversion tool able to predict the evolution of the complex permittivity (ε = ε′ – jε″) on a broad band frequency (f from 1 MHz to 1.8 GHz). Design/methodology/approach: The inverse problem is solved using adaptive network based fuzzy inference system (ANFIS) which needs the creation of a database for i ...Daha fazlası
BOUGHEDDA, Houssem | HACIB, Tarik | CHELABI, Mohamed | AÇIKGÖZ, Hulusi | LE BIHAN, Yan
This paper is concerned with the characterization methodologies of defects in conducting materials by an Electromagnetic Acoustic Transducer (EMAT) testing system. It has been developed to create a virtual environment for Non-Destructive Testing (NDT) before implementing it in real, to study the change effect on the defect geometry at the signal received. EMAT is a new technology, which provides a noncontact process of testing materials compared to ultrasonic testing technique. This work is based on the simulation of two-dimensional numerical model, using Finite Element Method, (FEM) like a si ...Daha fazlası
Electromagnetic (EM) structures such as antennas, resonators, are widely used in EM communication systems. It is not uncommon to find that the performance characteristics of these structures are not as expected because of the uncertainties introduced during the manufacturing process. These uncertainties may arise, for instance, from variations of the dimensions of the device or its material properties, e.g., permittivity and permeability. A statistical tool based on the use of the Polynomial Chaos Expansion (PCE) technique is proposed in this work. The results of investigation of two EM struct ...Daha fazlası
We present a stochastic modeling strategy for studying a wearable textile antenna under different manufacturing conditions. The studied device is a patch antenna designed for energy harvesting, which operates at the GSM and DCS bands, 900MHz and 1800MHz, respectively. The performance of the conductive patch printed on a textile substrate backed by a ground plane is investigated. A stochastic approach is employed to assess the variability of the observable because of the uncertainties introduced in the manufacturing process, such as laminating and embroidering.
AÇIKGÖZ, Hulusi | ARYA, Ravi Kumar | WIART, Joe | MITTRA, Raj
After a brief introduction, this chapter discusses the state of the art of variable antennas and previous works on these antennas are reviewed. This is followed by an introduction to the most common statistical analysis techniques used for the purpose of the uncertainty propagation. The application of the statistical method to some real case structures is then considered; split ring resonator (SRR) and wearable antennas.
SADOU, Hakim | HACIB, Tarik | LE BIHAN, Yan | MEYER, Olivier | AÇIKGÖZ, Hulusi
In this paper, the microwave characterization of dielectric materials using open-ended coaxial line probe is proposed. The measuring cell is a coaxial waveguide terminated by a dielectric sample. The study consists in extracting the real and imaginary part of the relative dielectric permittivity (ε = ε′-jε’’) of the material under test from the measurements of the probe admittance (Ymes(f) = Gmes(f)+jBmes(f)) on a broad band frequency (f between 1 MHz and 1.8 GHz), hence a direct and inverse problems have to be solved. In order to build a database, the direct problem is solved using Finite Ele ...Daha fazlası
In this paper, the internal homogenization method is introduced to determine the effective physical properties (permittivity and conductivity) of biological tissues. This method is performed on a 2D child head model obtained from MRI data. An original procedure where the complex 2D head model is represented as a multilayered circular structure is employed to retrieve the effective medium parameters. Results obtained with the proposed internal homogenization concept are compared with those obtained from the original heterogeneous model (with 4 tissues) and effective medium theories such as Maxw ...Daha fazlası
In this work we consider the problem of surface currents suppression using graphene in the context of microwave cancer treatment. Most of the research on graphene has been focused on its applications at terahertz frequencies, and not at microwave frequencies. The use of microwave cancer ablation technique using a coaxial slot antenna is being limited because of the existence of surface currents which lead to the heating of the healthy tissues along its outer surface. In this work we propose to use graphene which is a single-atom sheet of carbon, as a solution to prevent the propagation of surf ...Daha fazlası
SADOU, Hakim | HACIB, Tarik | LE BIHAN, Yan | AÇIKGÖZ, Hulusi | MEYER, Olivier
Inverse problems for determination of dielectric materials properties (complex permittivity) are usually solved by iterative methods using numerically based forward model. These methods are computationally expensive. In this paper, we propose a fast inversion model based on partial least square regression (PLSR). The idea is to build a model able to predict in real time the properties of the sample under test using measurements of admittance or reflexion coefficient of the propagating electromagnetic micro wave along the coaxial line. Numerical solution of the direct problem is made using Fini ...Daha fazlası
This paper presents the statistical analysis of a 3D printed flat lens by using the Polynomial Chaos Expansion (PCE) analysis technique. The flat lens is fabricated using the 3D printing technology and is based on the grading-index (GRIN) approach. It is composed of several concentric rings with graded relative permittivity, made of a single material with different air holes-host material volume ratio. We show that the hole size can have significant effect on the performance of the lens, especially on the focal distance. PCE analysis enables us also to determine the impact of each individual r ...Daha fazlası
6698 sayılı Kişisel Verilerin Korunması Kanunu kapsamında yükümlülüklerimiz ve cerez politikamız hakkında bilgi sahibi olmak için alttaki bağlantıyı kullanabilirsiniz.