Ferid Harabi

Direction of Arrival Estimation Method Using a 2-L Shape Arrays Antenna

The paper presents a new algorithm for a 2-dimensionnal direction of arrival estimation. Based on the extended Kalman filter (EKF), we analyse a recursive procedure for 2-dimensional directions of arrival (DOA) estimation and we will employ the two-L-shape arrays. A new space-variable model which we call a spatial state equation is presented using array element locations and incident angles. In this paper we briefly recapitulate the most important features of the extended Kalman filter (EKF). The performance of the proposed approach is examined by a simulation study with three signals model. The simulation results show a good estimate performance.

2-L-Shape Two-Dimensional Arrival Angle Estimation with a Classical Subspace Algorithm

This paper proposes a computationally efficient method for a two-dimensional direction of arrival estimation of multiple narrowband sources. We apply the MUSIC method which requires eigenvalues decomposition to the cross spectral matrix. This paper employs two L-shape arrays that showed better performances than the one L-shape and the parallel shape arrays. In spite of its computational complexity, simulation results verify that the proposed subspace technique gives much better performance than the propagator method

Estimation of 2-D Direction of Arrival with an Extended Correlation Matrix

This paper presents a new subspace-based 2D direction of arrival (DOA) estimation algorithm for narrowband sources with high-resolution localization capabilities. DOA estimation is achieved by using the noise-subspace eigenvectors of a new extended correlation matrix (ECM). A 2-L shape antenna array is proposed. Unlike common planar and circular arrays, the novel antenna array with this special geometry requires no pair matching between the azimuth and elevation angle estimation also this key can remove the drawbacks of estimation-failure problems. The performance of the proposed approach is examined by a simulation study. The simulation results show a good estimate performance.

A new estimation of direction of arrival algorithm with a special antenna shape

This paper presents a new subspace-based 2D direction of arrival (DOA) estimation algorithm for narrow-band sources with high-resolution localization capabilities. DOA estimation is achieved by using the noise-subspace eigenvectors of a new extended correlation matrix (ECM). A 2-L-shape antenna array is proposed. Unlike common planar and circular arrays, the novel antenna array with this special geometry requires no pair matching between the azimuth and elevation angle estimation. The performance of the proposed approach is examined by a simulation study in the presence of multiple wave fields. The simulation results show a good estimated performance of the proposed method.

Directions of arrival estimation with planar antenna arrays in the presence of mutual coupling

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.

QPSK demodulator based on six port junction

This article presents two different architectures of six port junctions operating at 2.45 GHz. One of those structures was based on a “branch line” coupler technology; the second junction is based on a circular coupler. both couplers have inputs connected to a Wilkinson power divider and the couplers used are hybrid couplers 90°/3dB. The simulation was performed using the Agilent ADS software technologies. The comparative study between the two junctions showed that a six ports junction using a circular coupler has better performance in terms of phase difference, loss, performance, reflection and isolation. The chosen configuration has been connected to power detectors to show its performance as a demodulator circuit.

Extended reactance domain algorithms for DoA estimation onto an ESPAR antennas

ABSTRACT Based on an extended reactance domain (RD) covariance matrix, this article proposes new alternatives for directions of arrival (DoAs) estimation of narrowband sources through an electronically steerable parasitic array radiator (ESPAR) antennas. Because of the centro symmetry of the classic ESPAR antennas, an unitary transformation is applied to the collected data that allow an important reduction in both computational cost and processing time and, also, an enhancement of the resolution capabilities of the proposed algorithms. Moreover, this article proposes a new approach for eigenvalues estimation through only some linear operations. The developed DoAs estimation algorithms based on this new approach has illustrated a good behaviour with less calculation cost and processing time as compared to other schemes based on the classic eigenvalues approach. The conducted simulations demonstrate that high-precision and high-resolution DoAs estimation can be reached especially in very closely sources situation and low sources power as compared to the RD-MUSIC algorithm and the RD-PM algorithm. The asymptotic behaviours of the proposed DoAs estimators are analysed in various scenarios and compared with the Cramer-Rao bound (CRB). The conducted simulations testify the high-resolution of the developed algorithms and prove the efficiently of the proposed approach.

A novel SIW six-port junction

Two architectures of a substrate integrated waveguide six-port junctions operating at 1.8 - 3.2 GHz were designed, simulated and compared at a center frequency of 2.45 GHz. The two structures composed of quadrature couplers were performed within an HFSS environment based on the finite element method (FEM) and printed on a Roger RT/duroid 6010. Simulation results of the SIW six-port junction without micro-strip lines showed much better performance than the other structure.

Space-time estimation algorithms for wideband signals

This paper deals with spatio-temporal analysis. The measurement of the directions of arrival using an antennas array is limited by the number of detected sources. In a linear network of M antennas, the maximum number of not correlated signals that can be localized is (M-1), and (2M/3) in case of correlated signals. Thus, the number of antennas must be higher than the number of signals. The spatio-temporal methods that are based on a joint estimation (angle-delay), overcome this difficulty. Here, a comparative study between two high-resolution wide-band algorithms that simultaneously estimate the travel time and the angle of arrival of the paths is presented. We will highlight the advantages of these two methods in the case of a joint estimation (angle-delay), via simulations.

MUSIC like algorithms for fast Direction of Arrival estimation

This paper proposes two Unitary MUSIC-like algorithms, requiring only linear operations, for Directions of Arrival (DoAs) estimation problem. The constraints on the proposed algorithms are the same imposed onto the standard MUSIC algorithm allowing high resolution localisation capabilities with a reduced computation cost and lower processing time as compared to the existing schemes. We demonstrate that the introduced Orthogonal Decompositions (OD) technique, for noise subspace estimation, can efficiently replace the requirement of Singular Value Decomposition (SVD) or Eigenvalue Decomposition (EVD) which leads to a reduced computational complexity and makes the DoAs estimation faster while maintaining comparable estimation accuracy. The simulation results confirm that high resolution DoAs estimation can be achieved by the developed methods and prove the validity of our approach.