Mohammad Rammal - Academia.edu (original) (raw)

Papers by Mohammad Rammal

Research paper thumbnail of Optimisation À La Synthèse Des Diagrammes De Rayonnement De Réseau D'Antennes Linéaires Par Les Réseaux De Neurones

Résumé: Le travail présenté dans cet article se rapporte à l'optimisation de la synthèse des ... more Résumé: Le travail présenté dans cet article se rapporte à l'optimisation de la synthèse des diagrammes de rayonnements de réseau d'antennes linéaires. La méthode de synthèse mise en oeuvre pour ce type de réseaux permet d'approcher à un diagramme de rayonnement désiré et trouver les pondérations complexes w ij pour que la fonction F R (ө,φ) réponde à des spécifications précises, souvent d'écrites par un gabarit. L'approche utilisée est basée sur de la méthode de Dolph-Tchebycheff et sur les réseaux de neurones qui sont capables de modéliser les diagrammes de rayonnements de réseau d'antennes linéaires, compte tenu de critères généraux prédéterminés, et finalement il permet de prédire le diagramme désiré à partir du modèle neural. Notre contribution principale dans cet article est l'extension d'un modèle de synthèse des diagrammes de rayonnement de ces réseaux à partir des pondérations. Mots clés : Réseau d'antennes linéaires, modélisation, réseau...

Research paper thumbnail of Synthèse de diagramme de rayonnement d'un réseau d'antennes linéaires par la méthode Dolph-Tchebycheff

Résumé: L'objectif de cet article est l'étude du phénomène de rayonnement du réseau d&#39... more Résumé: L'objectif de cet article est l'étude du phénomène de rayonnement du réseau d'antennes linéaire lorsque les sources sont pondérées, en particulier comment choisir la loi de pondérations pour que la répartition spatiale de la puissance rayonnée par le réseau considère satisfasse à des contraintes que l'on se fixe. La synthèse développée est basée sur la méthode de Dolphh-Tchebycheff. Mots clés : Réseaux d'antennes Dolph-Tchebycheff, synthèse, optimisation, diagramme de rayonnement.

Research paper thumbnail of An improved FDTD design of a wideband GSM patch antenna

Proceedings of the Twentieth National Radio Science Conference (NRSC'2003) (IEEE Cat. No.03EX665), 2003

ABSTRACT This paper describes a wideband resonant patch antenna for GSM system applications. A th... more ABSTRACT This paper describes a wideband resonant patch antenna for GSM system applications. A thick substrate is used to increase the bandwidth of such antenna. A new design method is suggested to solve the problem due to the inductance created by the probe feed. The 3D FDTD is used for the simulation of the antenna. A wide impedance matching bandwidth of 8% was reached. A good agreement is obtained between theoretical and practical results.

Research paper thumbnail of Low Power Injection for Direction Finding with Six-Port Reflectometer Array

Research paper thumbnail of Stability Study of Smart Antenna Systems using Homodyne Receivers for DOA Estimation

Research paper thumbnail of Adaptive beamforming synthesis for linear antenna array controlling only by phase with interference canceller

Research paper thumbnail of Performance comparison between 6-port and 5-port homodyne circuits for DOA estimation

In this paper, we propose two approaches to provide direction of arrival using homodyne detection... more In this paper, we propose two approaches to provide direction of arrival using homodyne detection systems technologies like six-port and five port reflectometers. The choice of the reflectometers' type becomes critical in parallel of the circuit capability, i.e. in terms of the number of signals to be detected simultaneously. We present our study by implementing MUSIC algorithm at the output of two different homodyne receivers. The results are deduced from the simulation of the characteristics of each system, using the Advanced Design System (ADS) and MATLAB.

Research paper thumbnail of Interests of a 1D EBG Matrix Compared to a Patch Array in terms of Mutual coupling and Grating Lobe

In this paper, we present a theoretical study on the interests of a 1D (one-dimensional) EBG Matr... more In this paper, we present a theoretical study on the interests of a 1D (one-dimensional) EBG Matrix versus the patch array, in terms of mutual coupling and grating lobes. To prove this interest, a comparison is made between these two antenna systems. The aim of this paper is to offer new antenna systems to the market for specific applications.

Research paper thumbnail of Experimental Validation of An Agile Electromagnetic Band Gap Matrix Antenna

This paper presents an experimental validation of a novel antenna system called “electromagnetic ... more This paper presents an experimental validation of a novel antenna system called “electromagnetic band gap matrix antenna”. The theoretical concept is based on the equivalent radiating surface approach and the antenna design is inspired from the electromagnetic band gap antennas. In this paper, an experimental validation is demonstrated to validate the theoretical concept of the antenna and several electromagnetic performances such as the low mutual coupling and the beam steering.

Research paper thumbnail of A Developed Excitation Law For Beam Forming And Steering Applied To A Novel Electromagnetic Band Gap Antenna

This paper presents an experimental validation of a developed feeding technique applied to a nove... more This paper presents an experimental validation of a developed feeding technique applied to a novel antenna system called electromagnetic band gap matrix antenna. The experimental validation will not only demonstrate the theoretical concept of the antenna, but it will also show the efficiency of applying a developed excitation law which enables us to obtain a sectorial radiation pattern presenting a quasi-constant gain over an angular range of 18° with low side lobes level less than -20 dB. The feeding technique process is described in this paper and some experimental results are presented to demonstrate the beam forming and steering capabilities of the matrix antenna.

Research paper thumbnail of A Novel Design of Phased Antenna Array Based on Digital Beamforming

The phased antenna array consists of a combination of multiple antenna elements with a signal-pro... more The phased antenna array consists of a combination of multiple antenna elements with a signal-processing capability to optimize its radiation and/or reception pattern automatically in response to the signal environment. In a telecommunication, the phased antenna array is the port through which radio frequency (RF) energy is coupled from the transmitter to the environment and, in reverse, to the receiver from the environment. In this paper, a novel design of phased antenna array based on digital beamforming is proposed. The goal of the design is to construct smart antenna beamforming systems with hardware-software implemented neural network. A newly proposed synthesis method is used to design antenna arrays capable of delivering a much better radiation performance in terms of homogenous coverage and reduced interference with phased arrays and capable to beamforming and electronic steering by adjusting the relative phases of the signal received or transmitted by each antenna. To verify the performances of the proposed technique, an 8-element array has been realized and tested for various types of beam configurations.

Research paper thumbnail of Agile radiating matrix antenna system for radar applications

2014 International Radar Conference, 2014

This paper presents an agile radiating matrix antenna which is formed by an association of severa... more This paper presents an agile radiating matrix antenna which is formed by an association of several and identical special radiating elements called 'pixels'. Those pixels have special properties concerning its radiating apertures. The matrix antenna working principle is based on the equivalent radiating surface approach and not on the classical array approach. The aim of this paper is to show the matrix antenna performances concerning its ability to achieve a great beam steering for high scanning angles which is used for target following and military bases monitoring in radar applications. The principle of this antenna constitutes the subject of an accepted CNRS (Centre National de la Recherche Scientifique) patent.

Research paper thumbnail of Feeding technique for the experimental validation of EBG matrix antenna

Microwave and Optical Technology Letters, 2015

ABSTRACT An experimental validation for the concept of a novel agile electromagnetic band gap mat... more ABSTRACT An experimental validation for the concept of a novel agile electromagnetic band gap matrix antenna is presented. It is used for beam forming and steering. It is fed by a cardinal sine excitation. A sectorial pattern is obtained. This pattern presents a special shape with low side lobes level. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:533–537, 2015

Research paper thumbnail of Steering an adaptive antenna array by LMS algorithm

2009 16th IEEE International Conference on Electronics, Circuits and Systems - (ICECS 2009), 2009

ABSTRACT An adaptive antenna system consists of a combination of multiple antenna elements with a... more ABSTRACT An adaptive antenna system consists of a combination of multiple antenna elements with a signal-processing capability to optimize its radiation and/or reception pattern automatically in response to the signal environment. In a telecommunication system, adaptive antenna system is the port through which radio frequency (RF) energy is coupled from the transmitter to the environment and, in reverse, to the receiver from the environment. In this paper, an efficient method for the pattern synthesis of the linear antenna arrays with the prescribed nulling and steering lobe is presented. The proposed method is based on LMS algorithm. This paper proposes the novel architecture for implementing a least mean square (LMS) algorithm, using an 8 quasi-Yagi array with its feeding system.

Research paper thumbnail of Design, development and experimental validation of a non-invasive device for recording respiratory events during bottle feeding

2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2014

In newborns, a poor coordination between sucking, swallowing and breathing may undermine the effe... more In newborns, a poor coordination between sucking, swallowing and breathing may undermine the effectiveness of oral feeding and signal immaturity of Central Nervous System. The aim of this work is to develop and validate a non-invasive device for recording respiratory events of newborns during bottle feeding. The proposed device working principle is based on the convective heat exchanged between two hot bodies and the infants' breathing. The sensing elements are inserted into a duct and the gas exchanged by infants is conveyed into this duct thanks to an ad hoc designed system to be mounted on a commercial feeding bottle.

Research paper thumbnail of Artificial Neural Networks ANN Approach for the Synthesis of Patch Antennas

2007 IEEE Radar Conference, 2007

Patch antennas plane networks have been used largely in communication systems. Their capability t... more Patch antennas plane networks have been used largely in communication systems. Their capability to change radiation pattern electronically, multi-beam capacity and high spatial resolution has made them attractive for mobile communication applications. The work presented in this paper refers to the synthesis of periodic patch antennas plane networks supplied with coaxial lines. The method of synthesis used for this type of networks let's possible an optimal approach for the desired radiation pattern specified by a gauge sensible for source excitation and space distribution of the radiant sources. The development of the synthesis is based on the neural networks technique.

Research paper thumbnail of General synthesis method for cylindrical antenna arrays for directive and conformal pattern

2009 16th IEEE International Conference on Electronics, Circuits and Systems - (ICECS 2009), 2009

This paper describes a new approach to cylindrical antenna controlled by the excitation (amplitud... more This paper describes a new approach to cylindrical antenna controlled by the excitation (amplitude and phase) to synthesize directive lobe and multilobe patterns, and create adaptive nulls in interference direction and large lobe pattern. The proposed method is based on iterative minimization of a function that incorporates constraints imposed in each direction with respect to excitation (amplitude and phase). To verify the performances of the proposed technique, an 16-element cylindrical antenna has been simulated for various types of beam configurations.

Research paper thumbnail of Interference Supression of the Linear Antenna Arrays Controlled by Phase with Use of SQP Algorithm

Progress In Electromagnetics Research, 2006

The performance of mobile cellular radio networks is limited by the level of cochannel interferen... more The performance of mobile cellular radio networks is limited by the level of cochannel interference that can be tolerated. The use of antennas arrays is very helpful in enhancing the performance and capacity of the wireless communication system. This paper presents a method for antenna pattern synthesis that suppress multiple interfering narrow or wide band signals while receiving the desired signal by controlling only the phase. Excitation phases are computed using the Sequential Quadratic Programming (SQP) technique. This method transforms the nonlinear minimization (or maximization) problem to a sequence of quadratic subproblems, based on a quadratic approximation of the Lagrangian function. 252 Mouhamadou et al.

Research paper thumbnail of Compensating for the mutual coupling effect on a synthesized pattern array

Microwave and Optical Technology Letters, 1996

ABSTRACT

Research paper thumbnail of New series-fed traveling-wave array

Microwave and Optical Technology Letters, 1994

A method of designing a series-fed microstrip traveling-wave array to produce a shaped pattern is... more A method of designing a series-fed microstrip traveling-wave array to produce a shaped pattern is described. A theoretical analysis of the traveling-wave element is given and experimental results are presented. High efJiciency and good directivity have been observed on the array. ABSTRACT A method of designing a series-fed microstrip traveling-wave array to produce a shaped pattern is described. A theoretical analysis of the traveling-wave element is given and experimental results are presented. High efJiciency and good directivity have been observed on the array. 0 ABSTRACT Plane-wave propagation in an anisotropic chiral medium with isotropic permittivity and permeability and symmetric chirality dyadic is considered. The eigenvalue equation is formed and the wave numbers and the corresponding eigenpolarizations are given. The results make possible the construction of a polarization transformer in which one can also choose the handedness. 0 I994 John Wiley & Sons, Inc.

Research paper thumbnail of Optimisation À La Synthèse Des Diagrammes De Rayonnement De Réseau D'Antennes Linéaires Par Les Réseaux De Neurones

Résumé: Le travail présenté dans cet article se rapporte à l'optimisation de la synthèse des ... more Résumé: Le travail présenté dans cet article se rapporte à l'optimisation de la synthèse des diagrammes de rayonnements de réseau d'antennes linéaires. La méthode de synthèse mise en oeuvre pour ce type de réseaux permet d'approcher à un diagramme de rayonnement désiré et trouver les pondérations complexes w ij pour que la fonction F R (ө,φ) réponde à des spécifications précises, souvent d'écrites par un gabarit. L'approche utilisée est basée sur de la méthode de Dolph-Tchebycheff et sur les réseaux de neurones qui sont capables de modéliser les diagrammes de rayonnements de réseau d'antennes linéaires, compte tenu de critères généraux prédéterminés, et finalement il permet de prédire le diagramme désiré à partir du modèle neural. Notre contribution principale dans cet article est l'extension d'un modèle de synthèse des diagrammes de rayonnement de ces réseaux à partir des pondérations. Mots clés : Réseau d'antennes linéaires, modélisation, réseau...

Research paper thumbnail of Synthèse de diagramme de rayonnement d'un réseau d'antennes linéaires par la méthode Dolph-Tchebycheff

Résumé: L'objectif de cet article est l'étude du phénomène de rayonnement du réseau d&#39... more Résumé: L'objectif de cet article est l'étude du phénomène de rayonnement du réseau d'antennes linéaire lorsque les sources sont pondérées, en particulier comment choisir la loi de pondérations pour que la répartition spatiale de la puissance rayonnée par le réseau considère satisfasse à des contraintes que l'on se fixe. La synthèse développée est basée sur la méthode de Dolphh-Tchebycheff. Mots clés : Réseaux d'antennes Dolph-Tchebycheff, synthèse, optimisation, diagramme de rayonnement.

Research paper thumbnail of An improved FDTD design of a wideband GSM patch antenna

Proceedings of the Twentieth National Radio Science Conference (NRSC'2003) (IEEE Cat. No.03EX665), 2003

ABSTRACT This paper describes a wideband resonant patch antenna for GSM system applications. A th... more ABSTRACT This paper describes a wideband resonant patch antenna for GSM system applications. A thick substrate is used to increase the bandwidth of such antenna. A new design method is suggested to solve the problem due to the inductance created by the probe feed. The 3D FDTD is used for the simulation of the antenna. A wide impedance matching bandwidth of 8% was reached. A good agreement is obtained between theoretical and practical results.

Research paper thumbnail of Low Power Injection for Direction Finding with Six-Port Reflectometer Array

Research paper thumbnail of Stability Study of Smart Antenna Systems using Homodyne Receivers for DOA Estimation

Research paper thumbnail of Adaptive beamforming synthesis for linear antenna array controlling only by phase with interference canceller

Research paper thumbnail of Performance comparison between 6-port and 5-port homodyne circuits for DOA estimation

In this paper, we propose two approaches to provide direction of arrival using homodyne detection... more In this paper, we propose two approaches to provide direction of arrival using homodyne detection systems technologies like six-port and five port reflectometers. The choice of the reflectometers' type becomes critical in parallel of the circuit capability, i.e. in terms of the number of signals to be detected simultaneously. We present our study by implementing MUSIC algorithm at the output of two different homodyne receivers. The results are deduced from the simulation of the characteristics of each system, using the Advanced Design System (ADS) and MATLAB.

Research paper thumbnail of Interests of a 1D EBG Matrix Compared to a Patch Array in terms of Mutual coupling and Grating Lobe

In this paper, we present a theoretical study on the interests of a 1D (one-dimensional) EBG Matr... more In this paper, we present a theoretical study on the interests of a 1D (one-dimensional) EBG Matrix versus the patch array, in terms of mutual coupling and grating lobes. To prove this interest, a comparison is made between these two antenna systems. The aim of this paper is to offer new antenna systems to the market for specific applications.

Research paper thumbnail of Experimental Validation of An Agile Electromagnetic Band Gap Matrix Antenna

This paper presents an experimental validation of a novel antenna system called “electromagnetic ... more This paper presents an experimental validation of a novel antenna system called “electromagnetic band gap matrix antenna”. The theoretical concept is based on the equivalent radiating surface approach and the antenna design is inspired from the electromagnetic band gap antennas. In this paper, an experimental validation is demonstrated to validate the theoretical concept of the antenna and several electromagnetic performances such as the low mutual coupling and the beam steering.

Research paper thumbnail of A Developed Excitation Law For Beam Forming And Steering Applied To A Novel Electromagnetic Band Gap Antenna

This paper presents an experimental validation of a developed feeding technique applied to a nove... more This paper presents an experimental validation of a developed feeding technique applied to a novel antenna system called electromagnetic band gap matrix antenna. The experimental validation will not only demonstrate the theoretical concept of the antenna, but it will also show the efficiency of applying a developed excitation law which enables us to obtain a sectorial radiation pattern presenting a quasi-constant gain over an angular range of 18° with low side lobes level less than -20 dB. The feeding technique process is described in this paper and some experimental results are presented to demonstrate the beam forming and steering capabilities of the matrix antenna.

Research paper thumbnail of A Novel Design of Phased Antenna Array Based on Digital Beamforming

The phased antenna array consists of a combination of multiple antenna elements with a signal-pro... more The phased antenna array consists of a combination of multiple antenna elements with a signal-processing capability to optimize its radiation and/or reception pattern automatically in response to the signal environment. In a telecommunication, the phased antenna array is the port through which radio frequency (RF) energy is coupled from the transmitter to the environment and, in reverse, to the receiver from the environment. In this paper, a novel design of phased antenna array based on digital beamforming is proposed. The goal of the design is to construct smart antenna beamforming systems with hardware-software implemented neural network. A newly proposed synthesis method is used to design antenna arrays capable of delivering a much better radiation performance in terms of homogenous coverage and reduced interference with phased arrays and capable to beamforming and electronic steering by adjusting the relative phases of the signal received or transmitted by each antenna. To verify the performances of the proposed technique, an 8-element array has been realized and tested for various types of beam configurations.

Research paper thumbnail of Agile radiating matrix antenna system for radar applications

2014 International Radar Conference, 2014

This paper presents an agile radiating matrix antenna which is formed by an association of severa... more This paper presents an agile radiating matrix antenna which is formed by an association of several and identical special radiating elements called 'pixels'. Those pixels have special properties concerning its radiating apertures. The matrix antenna working principle is based on the equivalent radiating surface approach and not on the classical array approach. The aim of this paper is to show the matrix antenna performances concerning its ability to achieve a great beam steering for high scanning angles which is used for target following and military bases monitoring in radar applications. The principle of this antenna constitutes the subject of an accepted CNRS (Centre National de la Recherche Scientifique) patent.

Research paper thumbnail of Feeding technique for the experimental validation of EBG matrix antenna

Microwave and Optical Technology Letters, 2015

ABSTRACT An experimental validation for the concept of a novel agile electromagnetic band gap mat... more ABSTRACT An experimental validation for the concept of a novel agile electromagnetic band gap matrix antenna is presented. It is used for beam forming and steering. It is fed by a cardinal sine excitation. A sectorial pattern is obtained. This pattern presents a special shape with low side lobes level. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:533–537, 2015

Research paper thumbnail of Steering an adaptive antenna array by LMS algorithm

2009 16th IEEE International Conference on Electronics, Circuits and Systems - (ICECS 2009), 2009

ABSTRACT An adaptive antenna system consists of a combination of multiple antenna elements with a... more ABSTRACT An adaptive antenna system consists of a combination of multiple antenna elements with a signal-processing capability to optimize its radiation and/or reception pattern automatically in response to the signal environment. In a telecommunication system, adaptive antenna system is the port through which radio frequency (RF) energy is coupled from the transmitter to the environment and, in reverse, to the receiver from the environment. In this paper, an efficient method for the pattern synthesis of the linear antenna arrays with the prescribed nulling and steering lobe is presented. The proposed method is based on LMS algorithm. This paper proposes the novel architecture for implementing a least mean square (LMS) algorithm, using an 8 quasi-Yagi array with its feeding system.

Research paper thumbnail of Design, development and experimental validation of a non-invasive device for recording respiratory events during bottle feeding

2014 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2014

In newborns, a poor coordination between sucking, swallowing and breathing may undermine the effe... more In newborns, a poor coordination between sucking, swallowing and breathing may undermine the effectiveness of oral feeding and signal immaturity of Central Nervous System. The aim of this work is to develop and validate a non-invasive device for recording respiratory events of newborns during bottle feeding. The proposed device working principle is based on the convective heat exchanged between two hot bodies and the infants' breathing. The sensing elements are inserted into a duct and the gas exchanged by infants is conveyed into this duct thanks to an ad hoc designed system to be mounted on a commercial feeding bottle.

Research paper thumbnail of Artificial Neural Networks ANN Approach for the Synthesis of Patch Antennas

2007 IEEE Radar Conference, 2007

Patch antennas plane networks have been used largely in communication systems. Their capability t... more Patch antennas plane networks have been used largely in communication systems. Their capability to change radiation pattern electronically, multi-beam capacity and high spatial resolution has made them attractive for mobile communication applications. The work presented in this paper refers to the synthesis of periodic patch antennas plane networks supplied with coaxial lines. The method of synthesis used for this type of networks let's possible an optimal approach for the desired radiation pattern specified by a gauge sensible for source excitation and space distribution of the radiant sources. The development of the synthesis is based on the neural networks technique.

Research paper thumbnail of General synthesis method for cylindrical antenna arrays for directive and conformal pattern

2009 16th IEEE International Conference on Electronics, Circuits and Systems - (ICECS 2009), 2009

This paper describes a new approach to cylindrical antenna controlled by the excitation (amplitud... more This paper describes a new approach to cylindrical antenna controlled by the excitation (amplitude and phase) to synthesize directive lobe and multilobe patterns, and create adaptive nulls in interference direction and large lobe pattern. The proposed method is based on iterative minimization of a function that incorporates constraints imposed in each direction with respect to excitation (amplitude and phase). To verify the performances of the proposed technique, an 16-element cylindrical antenna has been simulated for various types of beam configurations.

Research paper thumbnail of Interference Supression of the Linear Antenna Arrays Controlled by Phase with Use of SQP Algorithm

Progress In Electromagnetics Research, 2006

The performance of mobile cellular radio networks is limited by the level of cochannel interferen... more The performance of mobile cellular radio networks is limited by the level of cochannel interference that can be tolerated. The use of antennas arrays is very helpful in enhancing the performance and capacity of the wireless communication system. This paper presents a method for antenna pattern synthesis that suppress multiple interfering narrow or wide band signals while receiving the desired signal by controlling only the phase. Excitation phases are computed using the Sequential Quadratic Programming (SQP) technique. This method transforms the nonlinear minimization (or maximization) problem to a sequence of quadratic subproblems, based on a quadratic approximation of the Lagrangian function. 252 Mouhamadou et al.

Research paper thumbnail of Compensating for the mutual coupling effect on a synthesized pattern array

Microwave and Optical Technology Letters, 1996

ABSTRACT

Research paper thumbnail of New series-fed traveling-wave array

Microwave and Optical Technology Letters, 1994

A method of designing a series-fed microstrip traveling-wave array to produce a shaped pattern is... more A method of designing a series-fed microstrip traveling-wave array to produce a shaped pattern is described. A theoretical analysis of the traveling-wave element is given and experimental results are presented. High efJiciency and good directivity have been observed on the array. ABSTRACT A method of designing a series-fed microstrip traveling-wave array to produce a shaped pattern is described. A theoretical analysis of the traveling-wave element is given and experimental results are presented. High efJiciency and good directivity have been observed on the array. 0 ABSTRACT Plane-wave propagation in an anisotropic chiral medium with isotropic permittivity and permeability and symmetric chirality dyadic is considered. The eigenvalue equation is formed and the wave numbers and the corresponding eigenpolarizations are given. The results make possible the construction of a polarization transformer in which one can also choose the handedness. 0 I994 John Wiley & Sons, Inc.