Raafat Lababidi

Microstrip back-cavity Hilbert Fractal Antenna for experimental detection of breast tumors

This paper presents a miniaturized microstrip back-cavity Hilbert Fractal Antenna specifically designed for breast cancer detection. This antenna is used to investigate on the possibility of detecting the presence of breast tumors by directly measuring the shift of the antenna resonance frequency. First, simulations are performed on a multi-layer breast model; then the proposed approach was applied for in vivo measurements on two different patients diagnosed with breast cancer, followed by ex vivo characterization of the electrical properties of excised tumors.

A UWB antenna in direct breast contact for cancer detection

In this paper, a Ultra-Wide-Band (UWB) antenna of dimensions 3cm × 3cm, designed to be used in direct contact with the breast is presented. The breast phantom model, on which the antenna was designed, consists of four layers (skin, fat, glandular tissues and muscle with their specific thicknesses) taking into account the dielectric properties for each layer and their dependence versus frequency. The antenna has been optimized for many reasons: enhance the matching to the human body and maximize the transfer of energy into the breast phantom to increase the detection potential.

Miniature antenna for breast tumor detection

Microwave imaging is recognized as a potential candidate for biomedical applications, such as breast cancer detection. In this context a miniature antenna is used for quantitative imaging of inhomogeneous tissues. Microwave breast imaging (MBI) uses low power and longer wavelength signals to obtain information about breast tissues, and promises a safer and more accurate modality for regular breast scanning. This paper presents a miniature microstrip antenna that can be placed in contact with the breast model to investigate the presence of malignant tissues. A miniature antenna has been designed, and placed toward a breast phantom model with inhomogeneous tissues. Images are successfully obtained by using scattering electromagnetic waves (S11) from the designed model. The antenna was then manufactured and tested.

Miniaturized passive two-path notch filter for UWB receiver

In this paper, the RF characteristics of the flexible Kapton-based substrate are investigated by using the microstrip ring resonator in order to characterize the relative permittivity (εr) and loss tangent (tanδ) of the substrate at Ultra Wide Band (UWB) range. A compact notch filter using the approach of phase cancellation between two signal paths is also reported here. The passive notch filter is designed onto a Rogers4003-based substrate to test its performance. The integrated silicon chip is then reported on a grounded area of filter and connected to the output of this later by wire-bonding forming an SIP (System In Package) approach. The complete design is fully simulated using HFSS simulation tools, featuring high rejection at the central frequency and very low insertion loss far from the notch frequency.

RFID Eavesdropping Using SDR Platforms

Radio Frequency Identification (RFID) devices have been recently introduced in several applications and services such as National Identification Cards, Passports, Credit Cards, etc. In this paper, we investigate the security of such devices by showing the possibility of conducting RFID eavesdropping using simple and common devices such as a Software Defined Radio platform. Generally classical RF attacks can be made on long range transmission protocols, however we extend the standard RF attacks to cover RFID communication protocols. In this manuscript, an off-line step-by-step analysis is developed to prove the feasibility of reversing a complete RFID protocol. A real-time implementation is also realized to highlight a real threat in the everyday life.

Highly integrated Active Dual Response Filter

This work focuses on the design of a novel compact Active Dual Response Filter within a single device which allows ensuring the coexistence of three different standards while proposing an optimal structure in terms of response and space. The proposed filter is based on a highly selective low-pass filter at which a highly integrated compact notch filter is coupled. This co-integration of both filters is not a cascade so that the dual response filter occupies the same area as the low-pass filter alone. The Notch filter is set to 700 MHz and is loaded by an Active Capacitor (AC) circuit that allows a rejection at the notch central frequency of at least 19 dB. The low-pass filter cut-off frequency is Fc =890 MHz, the in band return loss is better than 20 dB. This methodology can be extended to various shapes of filter functions.

Compact highly selective passive notch filter for 3.1–5 GHz UWB receiver system

This paper deals with the design of highly selective passive notch filter working at 2.4 GHz for 3.1-5 GHz UWB receiver system. The proposed filter aims to enable IEEE 802.11 b/g and UWB standard coexistence in the same terminal device. The filter topology is composed of two paths: the first path contains an all-pass function while the second path contains a band-pass one. By this way, the signal is divided at the circuit input and is combined at its output forming a notch response that exhibits a high rejection at the center frequency of the band-pass filter function. Experimental prototype implemented on Rogers4003 multilayer substrate is built in order to show the benefit of this concept design.

Highly flexible active notch filter for Cognitive Radio

Nowadays, many wireless communication devices should share the precious radio-frequency bandwidths. In order to get the most of the available spectrum, Cognitive Radio (CR) are recently introduced to allow better spectrum management for newly standardized radio communication systems. An advanced multistandard terminal device may cover several communication standards. The system of such device should be highly flexible to dynamically and autonomously adjust its radio operating parameters. Moreover, the reduction of interference among radio communication systems is needed to allow the coexistence of different standards in the same device. In this paper, a new concept and system architecture to reach our goal are proposed and discussed. Our ultimate goal aims to ensure the coexistence of different standards in a CR mobile terminal.