Unit of Research in High Frequency Electronic Circuits and Systems

Qal‘at al Andalus, Tunisia

Unit of Research in High Frequency Electronic Circuits and Systems

Qal‘at al Andalus, Tunisia
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Jmai B.,Unit of Research in High Frequency Electronic Circuits and Systems | Rajhi A.,National Engineering School of Tunis | Rajhi A.,Laboratory of Physics Soft Materials and em Modelisation | Gharsallah A.,Unit of Research in High Frequency Electronic Circuits and Systems
2nd International Conference on Advanced Technologies for Signal and Image Processing, ATSIP 2016 | Year: 2016

The antenna chips becomes very important component in microwave applications and for the wireless communication industry. In this work, different Coplanar Waveguide (CPW) antenna above-IC (integrate circuit) are analyzed and simulated by high frequency structural simulator (HFSS) based on finite element method (FEM). A comparative study has been done on their performances of different types of CPW antenna with some geometrical dimension. Furthermore, the return loss and radiation pattern were investigate in terms of gain radiation and directivity. The simulation results show that it is possible to have multiband CPW antenna by changing the geometry of the radio frequency (RF) patch in the shape of inverse U with a split-ring resonator. © 2016 IEEE.


Akkar S.,Unit of Research in High Frequency Electronic Circuits and Systems | Harabi F.,Unit of Research in High Frequency Electronic Circuits and Systems | Gharsallah A.,Unit of Research in High Frequency Electronic Circuits and Systems
LAPC 2012 - 2012 Loughborough Antennas and Propagation Conference | Year: 2012

This paper proposes a new Uniform Concentric Circular (UCCA) shaped Electronically Steerable Parasitic Array Radiator (ESPAR) antennas for Directions of Arrival (DoAs) estimation problem. The well known ESPRIT algorithm is adapted to this special shape of UCCA and we demonstrate the resulting algorithm yields to a better DoAs estimation accuracy and solves the failure of estimation problem associated with the signals' DoAs in some particular sectors: notably when they range [0°-30°] and [160°-180°]. This approach has shown interesting performances for the entire half azimuth plane without any extra overhead computations. The Cramer Rao Bound on the variance of DoAs estimated by the proposed ESPAR antennas shape is analysed. The simulations results confirm that this new shape of UCCA not only provides superior high resolution localisation capabilities but also considerably reduces both calculation cost and processing time of the DoAs estimator compared with previous works based on the Uniform Hexagonal Array shape (UHA). © 2012 IEEE.


Akkar S.,Unit of Research in High Frequency Electronic Circuits and Systems | Harabi F.,Unit of Research in High Frequency Electronic Circuits and Systems | Gharsallah A.,Unit of Research in High Frequency Electronic Circuits and Systems
Mediterranean Microwave Symposium | Year: 2011

This paper proposes a self-calibration algorithm, that requires only real valued operations, to estimate the Directions of Arrival (DoAs) of correlated sources in the presence of unknown Mutual coupling. Based on the standard MUSIC algorithm and with respect to the same imposed constraints, we develop the Iterative Unitary-MUSIC algorithm that provides superior high resolution localisation capabilities even for correlated sources scenarios with a reduced computations cost as well as a low processing time compared with previous works. In our analysis, the induced Electro-Motive Force (EMF) method is used to model the mutual coupling matrix. Through computer simulations, we demonstrate that our approach has more interesting performances even if all coupling parameters are included and especially when the incoming signals are highly correlated. Moreover, we drive more flexible identifiability conditions for the uniqueness of the estimation solution that required a reduced number of sensors to estimate the same number of parameters compared with previous works. © 2011 IEEE.


Alayet S.,Unit of Research in High Frequency Electronic Circuits and Systems | Latrach L.,Unit of Research in High Frequency Electronic Circuits and Systems | Gharsallah A.,Unit of Research in High Frequency Electronic Circuits and Systems
International Journal on Communications Antenna and Propagation | Year: 2016

This paper discusses one approach for modeling and designing Vivaldi antennas by an iterative method using surface impedance for reducing surface waves in antenna. The technique of the Wave Concept Iterative Procedure is based on two equations; one is in the spatial domain and the other in the spectral domain. The passage between the two domains is based on Transform Fourier Mode FMT. A comparative study is presented between the iterative method and the CST software. The results were obtained in a very reduced time compared that those obtained by the simulation software. © 2016 Praise Worthy Prize S.r.l. - All rights reserved.


Nasri A.,Unit of Research in High Frequency Electronic Circuits and Systems | Zairi H.,Unit of Research in High Frequency Electronic Circuits and Systems | Gharsallah A.,Unit of Research in High Frequency Electronic Circuits and Systems
International Journal of Electrical and Computer Engineering | Year: 2014

The present paper highlights an innovative broadband millimeter-wave single balanced diode mixer which is designed using a newly designed 90 substrate integrated waveguide (SIW) coupler and two cavities (SIW) filter. The mixer covers RF/LO operating frequency range which fluctuates between 10 to 12 GHz and IF port covers 2GHz. The proposed mixer exhibits a fairly low conversion loss of less than 10 dB and high port to-port isolations over the frequency band of interest as the simulated results make clear. Furthermore, the two cavities SIW filter is embedded to achieve a better image frequency suppression of about 28dB. Copyright © 2014 Institute of Advanced Engineering and Science. All rights reserved.


Akkar S.,Unit of Research in High Frequency Electronic Circuits and Systems | Harabi F.,Unit of Research in High Frequency Electronic Circuits and Systems | Gharsallah A.,Unit of Research in High Frequency Electronic Circuits and Systems
International Journal of Electronics | Year: 2013

Directions of arrival (DoAs) estimation of multiple sources using an antenna array is a challenging topic in wireless communication. The DoAs estimation accuracy depends not only on the selected technique and algorithm, but also on the geometrical configuration of the antenna array used during the estimation. In this article the robustness of common planar antenna arrays against unaccounted mutual coupling is examined and their DoAs estimation capabilities are compared and analysed through computer simulations using the well-known MUltiple SIgnal Classification (MUSIC) algorithm. Our analysis is based on an electromagnetic concept to calculate an approximation of the impedance matrices that define the mutual coupling matrix (MCM). Furthermore, a CRB analysis is presented and used as an asymptotic performance benchmark of the studied antenna arrays. The impact of the studied antenna arrays geometry on the MCM structure is also investigated. Simulation results show that the UCCA has more robustness against unaccounted mutual coupling and performs better results than both UCA and URA geometries. The performed simulations confirm also that, although the UCCA achieves better performance under complicated scenarios, the URA shows better asymptotic (CRB) behaviour which promises more accuracy on DoAs estimation. © 2013 Taylor & Francis Group, LLC.


Mabrouki M.,Unit of Research in High Frequency Electronic Circuits and Systems | Ghayoula R.,Unit of Research in High Frequency Electronic Circuits and Systems | Gharsallah A.,Unit of Research in High Frequency Electronic Circuits and Systems
2nd International Conference on Advanced Technologies for Signal and Image Processing, ATSIP 2016 | Year: 2016

Phase shifters present the key components in the field of phased array antenna. They are used to electrically shape and steer the antenna beam. In this paper, the design and simulation of S-band 6-bits phase shifter based on semiconductor switch is suggested. The proposal is designed by combining the properties of reflection and switched lines and it consists of two stages. The first stage is realized in switched-reflection topology and it is composed by a branch line coupler, a semiconductor switch and vertical and horizontal delay lines. The second stage is composed of two cells of serial cascade switched delay line. The two stages are integrated to increase the phase shifter resolution. Our proposal is validated through numerical simulation and we show that our 6-bits integrated phase shifter is capable of providing 64 different phases separated by 5.625° over the frequency band 2.2-2.6 GHz. © 2016 IEEE.


Smida A.,Unit of Research in High Frequency Electronic Circuits and Systems | Ghayoula R.,Unit of Research in High Frequency Electronic Circuits and Systems | Troudi A.,Unit of Research in High Frequency Electronic Circuits and Systems | Trabelsi H.,Unit of Research in High Frequency Electronic Circuits and Systems | Gharsallah A.,Unit of Research in High Frequency Electronic Circuits and Systems
2012 9th International Conference on Communications, COMM 2012 - Conference Proceedings | Year: 2012

The objective of this paper is to present a beam synthesis technique for circular antenna array antennas with efficient tapering. This paper describes a Taguchi to synthesize circular antenna arrays controlled by the phase and amplitude excitation, to synthesize directive lobe. The advantage of Taguchi's optimization technique is the ability of solving problems with a high degree of complexity using a small number of experiments in the optimization process Taguchi's method is easy to implement and converges to the desired goal quickly. An 16-element circular antenna has been simulated and tested for various types of beam configurations. © 2012 IEEE.

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