Amer Zakaria | American University of Sharjah (original) (raw)

Papers by Amer Zakaria

2016 16th Mediterranean Microwave Symposium (MMS), 2016

IEEE Transactions on Microwave Theory and Techniques, 2016

2015 USNC-URSI Radio Science Meeting (Joint with AP-S Symposium), 2015

... Deepali Deshpande, Arun K. Somani Electrical and Computer Engineering Department Iowa State U... more ... Deepali Deshpande, Arun K. Somani Electrical and Computer Engineering Department Iowa State University, Ames 50011 E-Mail: {deepa, arun}@iastate.edu Akhilesh Tyagi Computer Science Department Iowa State University, Ames 50011 E-Mail: tyagi@iastate.edu Abstract ...

ABSTRACT Microwave tomography is enhanced by using an inhomogeneous background. In this paper, th... more ABSTRACT Microwave tomography is enhanced by using an inhomogeneous background. In this paper, the measurement region is located in a circular perfect electrical conductor (PEC) chamber where a known object is placed inside the imaging domain as an inhomogeneous background. This can not only make use of the prior information about the background, but also increase the equivalent radiation source for the target detection. The Green function of a circular PEC chamber with inhomogeneous background is obtained using the method of moments. Based on the Green functions for both homogeneous and inhomogeneous background in circular PEC chamber, the properties of the radiation operators are analyzed by comparing the condition numbers and the singular value spectra. Simulations are carried out in homogeneous, lossless inhomogeneous and lossy inhomogeneous backgrounds respectively, and the relative errors are discussed. The results show that using inhomogeneous background can improve the convergence rate and accuracy, and the lossy inhomogeneous background produces better results than the lossless one. In addition, it can enhance the inversion results without changing the microwave tomography system, which can be used in the medical imaging and industrial nondestructive detection.

Ultra-Wideband, Short-Pulse Electromagnetics 10, 2013

2008 Asia-Pacific Symposium on Electromagnetic Compatibility and 19th International Zurich Symposium on Electromagnetic Compatibility, 2008

... Arnd Frech #1, Amer Zakaria #2, Stephan Braun #3, Peter Russer #4 # Institute for High-Freque... more ... Arnd Frech #1, Amer Zakaria #2, Stephan Braun #3, Peter Russer #4 # Institute for High-Frequency Engineering, Technische Universität München 80333 Munich, Germany 1 frech@tum.de 2 azakaria@ee ... The peak detector formulation is given by Xp = MAX{X[n]|nϵ{1...N}}. (3) ...

International Zurich Symposium on Electromagnetic Compatibility, 2008

In this paper, an advanced digital signal processing technique for fast measurements of electroma... more In this paper, an advanced digital signal processing technique for fast measurements of electromagnetic interference from electronic devices in the time-domain at open area test sites will be presented. Suppressing ambient noise by methods based on adaptive filtering algorithms, measurements of electromagnetic interference of a device under test can be performed at a test site polluted with electromagnetic ambient noise. Frequency domain adaptive filtering using the overlap-save method is applied. Measurement results of a real device under test are presented which show the successful cancellation of ambient noise at an urban test site in the frequency range 30 to 1000 MHz.

2013 USNC-URSI Radio Science Meeting (Joint with AP-S Symposium), 2013

ABSTRACT Microwave tomography (MWT) or microwave imaging spectroscopy (MIS) has been studied as a... more ABSTRACT Microwave tomography (MWT) or microwave imaging spectroscopy (MIS) has been studied as a promising low-cost portable alternative or complementary biomedical diagnostic technique for conventional soft-tissue imaging modalities for several years. The ability to quantitatively reconstruct unique, diagnostically useful properties of the tissue of interest (i.e. the permittivity and effective conductivity) at safe, non-ionizing frequency ranges without the need of a contrast agent has been among MWT's frequently quoted advantages, especially in the context of its most developed application in breast imaging. However, recent large-scale studies characterizing the ultra-wideband dielectric properties of freshly excised breast tissues have shown that the contrast between malignant breast carcinoma and normal fibroconnective/glandular tissue is inherently low (M. Lazebnik et al., Phys. Med. Biol. 52, 6093-6115, 2007), making it clear that this emerging technology could benefit from the use of exogenous contrast agents that selectively accumulate in cancerous tissues. This concession has spurred interest in the study of conventional and novel contrast agents in the field of microwave imaging, with recent publications employing microbubbles (S.C. Hagness et al., Phys. Med. Biol., 54, 641-650, 2009), single-walled carbon nanotubes (S.C. Hagness et al., IEEE Trans. BME, 57, 8, 1831-1834, 2010), and magnetic nanocomposites (O.M. Bucci et al., IEEE Trans. BME, 58, 9, 2528-2536, 2011) demonstrating encouraging results. A broad study of contrast agents, including compounds traditionally employed in nuclear medicine procedures (albeit using their radioactively-inert isotopic counterparts) and other conventional anatomical imaging modalities, is conducted to assess their feasibility for microwave imaging. The search is expanded to explore not only tumour markers, but any organic or non-organic chemical compounds whose distribution within live tissues could yield useful functional, p- ysiological information. Examples include potassium analogues (rubidium, cesium), tracers for inflammation and rapid cell division (gallium, flurodeoxyglucose), tissue oxygenation markers (nitroxide and trityl radicals), blood pool agents (gadolinium-based complexes) and functionalized magnetic nanoparticles (iron oxide nanocrystals). Such chemical species with favourable complex permittivity measured in solution over a frequency range of interest are evaluated as potential MWT contrast agents for in vivo imaging applications based on similar criteria that govern their selection for other modalities. These criteria include chemical stability and water solubility, pharmacological half-life and method of clearance, ease of administration, cost and availability, and selectivity of the agent's biodistribution. The compound should demonstrate sufficient cellular uptake to significantly affect dielectric contrast in tissues of interest and most importantly, exhibit no biological toxicity at the concentrations required to obtain said contrast.

2013 IEEE Antennas and Propagation Society International Symposium (APSURSI), 2013

ABSTRACT A finite element contrast source inversion algorithm was used to invert synthetic contra... more ABSTRACT A finite element contrast source inversion algorithm was used to invert synthetic contrast enhanced breast data in order to determine the location of tumours. Prior information about the anatomy and the electrical properties of the breast model, which is obtained by a blind inversion before adding the contrast agent, is incorporated in order to increase the likelihood of successfully locating the tumours. Simulating the use of a contrast agent by increasing the permittivity of the tumours allows for a positive detection of their position. This method was also applied to data obtained from a numerical human forearm phantom in order to show applicability to anatomical regions with varying homogeneity.

2014 USNC-URSI Radio Science Meeting (Joint with AP-S Symposium), 2014

Proceedings of the 2012 IEEE International Symposium on Antennas and Propagation, 2012

ABSTRACT The contrast source inversion algorithm coupled to a finite-element method (FEM) has bee... more ABSTRACT The contrast source inversion algorithm coupled to a finite-element method (FEM) has been implemented for three-dimensional (3D) full-vectorial problems. The algorithm solves inverse scattering problems associated with microwave imaging applications. The use of FEM to discretize the Helmholtz differential operator allows the unknown electrical properties of the inverse problem to be distributed on the elements of arbitrary meshes with varying densities. The paper presents an evaluation of the computational complexity of the algorithm and delineates the relevant choices with respect to implementation. The algorithm is validated using multi-frequency experimental datasets collected by the Institut Fresnel of Marseille, France.

2009 13th International Symposium on Antenna Technology and Applied Electromagnetics and the Canadian Radio Science Meeting, 2009

Abstract Thin-wire models for the FVTD algorithm are validated using various monopole configurati... more Abstract Thin-wire models for the FVTD algorithm are validated using various monopole configurations above a finite ground plane. The thin-wire model is derived from the original Holland-Simpson formulation, extended by Edelvik for the finite-element method, and ...

Progress In Electromagnetics Research, 2014