The Experts below are selected from a list of 5058 Experts worldwide ranked by ideXlab platform
T K Sarkar - One of the best experts on this subject based on the ideXlab platform.
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interpolation of high frequency data by using Matrix Pencil and greens s function
IEEE Antennas and Propagation Society International Symposium, 2008Co-Authors: Jie Yang, M Taylor, Yu Zhang, T K SarkarAbstract:In this paper a novel interpolation approach is proposed to reduce the number of samples required for system response reconstruction. We explore the effect of complex exponential term e-jkr (which is the numerator part of Greenpsilas function) in electromagnetic field, which causes the oscillation in system response especially in the high frequency domain. If it is divided from the field quantity, even though the magnitude is unchanged, both real and imaginary parts of the frequency response become smoother. The interpolation is performed separately for both real and imaginary parts so that the sample rate required for accurate reconstruction is significantly reduced. The interpolation is carried out by Matrix Pencil method and the coefficients of which are calculated by using the total least square (TLS) implementation to improve the accuracy. Numerical examples are presented to illustrate the applicability of this unique approach in ultra-high frequency bands.
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2 d unitary Matrix Pencil method for efficient direction of arrival estimation
Digital Signal Processing, 2006Co-Authors: Nuri Yilmazer, T K SarkarAbstract:In this study, we extended the one-dimensional (1-D) unitary Matrix Pencil method (UMP) [N. Yilmazer, J. Koh, T.K. Sarkar, Utilization of a unitary transform for efficient computation in the Matrix Pencil method to find the direction of arrival, IEEE Trans. Antennas Propagat. 54 (1) (2006) 175-181] to two-dimensional case, where 2-D Matrix Pencil (MP) method are used to find the 2-D poles corresponding to the direction of arrival (DOA), azimuth and elevation angles, of the far field sources impinging on antenna arrays. This technique uses MP method to compute the DOA of the signals using a very efficient computational procedure in which the complexity of the computation can be reduced significantly by using a unitary Matrix transformation. This method applies the technique directly to the data without forming a covariance Matrix. Using real computations through the unitary transformation for the 2-D Matrix Pencil method leads to a very efficient computational methodology for real time implementation on a DSP chip. The numerical simulation results are provided to see the performance of the method.
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Efficient computation of the azimuth and elevation angles of the sources by using unitary Matrix Pencil method (2-D UMP)
2006 IEEE Antennas and Propagation Society International Symposium, 2006Co-Authors: Nuri Yilmazer, T K SarkarAbstract:In this study, we extended the 1-dimensional (1-D) unitary Matrix Pencil method to 2-dimensional case, where 2-D Matrix Pencil method are used to find the 2-D poles corresponding to the direction of arrival, azimuth and elevation angles, of the far field sources impinging on antenna arrays. This technique uses Matrix Pencil (MP) method to compute the direction of arrival (DOA) of the signals using a very efficient computational procedure in which the complexity of the computation can be reduced significantly by using a unitary Matrix transformation. This method applies the technique directly to the data without forming a covariance Matrix. Using real computations through the unitary transformation for the 2-D Matrix Pencil method leads to a very efficient computational methodology for real time implementation on a DSP chip. The numerical simulation results are provided to see the performance of the method. The simulation results show that for the low signal to noise ratio (SNR) cases the new 2-D unitary Matrix Pencil method outperforms the current 2-D MP method
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computation of the sommerfeld integral tails using the Matrix Pencil method
IEEE Transactions on Antennas and Propagation, 2006Co-Authors: Mengtao Yuan, T K SarkarAbstract:The oscillating infinite domain Sommerfeld integrals (SI) are difficult to integrate using a numerical procedure when dealing with structures in a layered media, even though several researchers have attempted to do that. Generally, integration along the real axis is used to compute the SI. However, significant computational effort is required to integrate the oscillating and slowly decaying function along the tail. Extrapolation methods are generally applied to accelerate the rate of convergence of these integrals. However, there are difficulties with the extrapolation methods, such as locations for the breakpoints. In this paper, we illustrate a simplified approach for accurate and efficient calculation of the integrals dealing with the tails of the SI. In this paper, we fit the tail by a sum of finite (usually 10 to 20) complex exponentials using the Matrix Pencil method (MPM). The integral of the tail of the SI is then simply calculated by summing some complex numbers. No numerical integration is needed in this process, as the integrals can be done analytically. Good accuracy is achieved with a small number of evaluations for the integral kernel (60 points for the MPM as compared with hundreds or thousands of functional evaluations using the traditional extrapolation methods) along the tails of the SI. Simulation results show that to obtain the similar accuracy in the evaluation of the SI, the MPM is approximately 10 times faster than the traditional extrapolation methods. Moreover, since the MPM is robust to the effects of noise, this method is more stable, especially for large values of the horizontal distances. The method proposed in this paper is thus a new and better technique to obtain accurate results for the computation of the Green's function for a layered media in the spatial domain.
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utilization of a unitary transform for efficient computation in the Matrix Pencil method to find the direction of arrival
IEEE Transactions on Antennas and Propagation, 2006Co-Authors: Nuri Yilmazer, T K SarkarAbstract:In this study, we use the Matrix Pencil (MP) method to compute the direction of arrival (DOA) of the signals using a very efficient computational procedure in which the complexity of the computation can be reduced significantly by using a unitary Matrix transformation. This method applies the technique directly to the data without forming a covariance Matrix. Simulation results show that the variance of the estimate approaches to the Cramer-Rao lower bound. Using real computations through the unitary transformation for the MP method leads to a very efficient computational methodology for real time implementation on a digital signal processor chip. A unitary transform can convert the complex Matrix to a real Matrix along with their eigenvectors and thereby reducing the computational cost at least by a factor of four without sacrificing accuracy. This reduction in the number of computations is achieved by using a transformation, which maps centro-hermitian matrices to real matrices. This transformation is based on Lee's work on centro-hermitian matrices.
Zaiping Nie - One of the best experts on this subject based on the ideXlab platform.
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reducing the number of elements in multiple pattern linear arrays by the extended Matrix Pencil methods
IEEE Transactions on Antennas and Propagation, 2014Co-Authors: Yanhui Liu, Qing Huo Liu, Zaiping NieAbstract:Previously, the Matrix Pencil method (MPM) and the forward-backward MPM (FBMPM) were used to effectively reduce the number of antenna elements in the single-pattern linear arrays. This work extends the MPM and FBMPM-based synthesis methods to the synthesis of multiple-pattern linear arrays with a smaller number of elements. The extended MPM (resp., the extended FBMPM) method organizes all the multiple pattern data into a composite Hankel (resp., composite Hankel-Toeplitz) Matrix from which the minimum number of elements and the common poles corresponding to element positions can be obtained with similar processing used in the original MPM or FBMPM synthesis method. In particular, the extended FBMPM inherits the advantage of the original FBMPM that a useful restriction is put on the distribution of poles, which makes the element positions obtained much more accurate and robust. Numerical experiments are conducted to validate the effectiveness and robustness of the proposed methods. For the tested cases, the element saving is about 20% ~ 25% for reconfigurable shaped patterns, and can be even more for electrically large linear arrays with scanned Pencil-beams.
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reducing the number of elements in the synthesis of shaped beam patterns by the forward backward Matrix Pencil method
IEEE Transactions on Antennas and Propagation, 2010Co-Authors: Yanhui Liu, Qing Huo Liu, Zaiping NieAbstract:The Matrix Pencil method (MPM) has been used to reduce the number of elements in the linear antenna array with a Pencil-beam pattern. This work extends the MPM-based synthesis method to the synthesis of shaped-beam patterns by using the forward-backward Matrix Pencil method (FBMPM). The FBMPM-based synthesis method places a necessary restriction on the poles which correspond to element positions, and consequently obtains more accurate synthesis results, particularly for the synthesis of asymmetric patterns. Numerical examples show the effectiveness and advantages of the proposed method in the reduction of the number of elements for shaped-beam patterns.
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reducing the number of elements in a linear antenna array by the Matrix Pencil method
IEEE Transactions on Antennas and Propagation, 2008Co-Authors: Yanhui Liu, Zaiping Nie, Qing Huo LiuAbstract:The synthesis of a nonuniform antenna array with as few elements as possible has considerable practical applications. This paper introduces a new non-iterative method for linear array synthesis based on the Matrix Pencil method (MPM). The method can synthesize a nonuniform linear array with a reduced number of elements, and can be also used to reduce the number of elements for linear arrays designed by other synthesis techniques. In the proposed method, the desired radiation pattern is first sampled to form a discrete pattern data set. Then we organize the discrete data set in a form of Hankel Matrix and perform the singular value decomposition (SVD) of the Matrix. By discarding the non-principal singular values, we obtain an optimal lower-rank approximation of the Hankel Matrix. The lower-rank Matrix actually corresponds to fewer antenna elements. The Matrix Pencil method is then utilized to reconstruct the excitation and location distributions from the approximated Matrix. Numerical examples show the effectiveness and advantages of the proposed synthesis method.
Fuhgwo Yuan - One of the best experts on this subject based on the ideXlab platform.
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extraction of guided wave dispersion curve in isotropic and anisotropic materials by Matrix Pencil method
Ultrasonics, 2018Co-Authors: Fuhgwo Yuan, C Y ChangAbstract:Abstract Guided wave dispersion curves in isotropic and anisotropic materials are extracted automatically from measured data by Matrix Pencil (MP) method investigating through k-t or x-ω domain with a broadband signal. A piezoelectric wafer emits a broadband excitation, linear chirp signal to generate guided waves in the plate. The propagating waves are measured at discrete locations along the lines for one-dimensional laser Doppler vibrometer (1-D LDV). Measurements are first Fourier transformed into either wavenumber-time k-t domain or space-frequency x-ω domain. MP method is then employed to extract the dispersion curves explicitly associated with different wave modes. In addition, the phase and group velocity are deduced by the relations between wavenumbers and frequencies. In this research, the inspections for dispersion relations on an aluminum plate by MP method from k-t or x-ω domain are demonstrated and compared with two-dimensional Fourier transform (2-D FFT). Other experiments on a thicker aluminum plate for higher modes and a composite plate are analyzed by MP method. Extracted relations of composite plate are confirmed by three-dimensional (3-D) theoretical curves computed numerically. The results explain that the MP method not only shows more accuracy for distinguishing the dispersion curves on isotropic material, but also obtains good agreements with theoretical curves on anisotropic and laminated materials.
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dispersion curve extraction of lamb waves in metallic plates by Matrix Pencil method
Proceedings of SPIE, 2017Co-Authors: Cheyuan Chang, Fuhgwo YuanAbstract:Lamb wave dispersion curves for isotropic plates are extracted from measured sensor data by Matrix Pencil (MP) method. A piezoelectric wafer emits a linear chirp signal as broadband excitation to generate Lamb waves in isotropic plates. The propagating waves are measured at discrete locations along a wave ray direction with a sensor 1-D laser Doppler vibrometer (LDV). The out-of-plane velocities are first Fourier transformed into either space-frequency x-ω domain or wavenumber-time k-t domain. The Matrix Pencil method is then employed to extract the dispersion curves for various wave modes simultaneously. In addition, the phase and group velocity dispersion curves are deduced by the relation between wavenumber and frequency. In this research, the inspections for dispersion relations on isotropic plates are demonstrated and compared by two-dimensional Fourier transform (2D-FFT) and MP method. The results are confirmed by theoretical curves computed numerically. It has demonstrated that the MP method is robust in recognining/differentiating different wave modes, including higher order ones.
Yanhui Liu - One of the best experts on this subject based on the ideXlab platform.
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reducing the number of elements in multiple pattern linear arrays by the extended Matrix Pencil methods
IEEE Transactions on Antennas and Propagation, 2014Co-Authors: Yanhui Liu, Qing Huo Liu, Zaiping NieAbstract:Previously, the Matrix Pencil method (MPM) and the forward-backward MPM (FBMPM) were used to effectively reduce the number of antenna elements in the single-pattern linear arrays. This work extends the MPM and FBMPM-based synthesis methods to the synthesis of multiple-pattern linear arrays with a smaller number of elements. The extended MPM (resp., the extended FBMPM) method organizes all the multiple pattern data into a composite Hankel (resp., composite Hankel-Toeplitz) Matrix from which the minimum number of elements and the common poles corresponding to element positions can be obtained with similar processing used in the original MPM or FBMPM synthesis method. In particular, the extended FBMPM inherits the advantage of the original FBMPM that a useful restriction is put on the distribution of poles, which makes the element positions obtained much more accurate and robust. Numerical experiments are conducted to validate the effectiveness and robustness of the proposed methods. For the tested cases, the element saving is about 20% ~ 25% for reconfigurable shaped patterns, and can be even more for electrically large linear arrays with scanned Pencil-beams.
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reducing the number of elements in the synthesis of shaped beam patterns by the forward backward Matrix Pencil method
IEEE Transactions on Antennas and Propagation, 2010Co-Authors: Yanhui Liu, Qing Huo Liu, Zaiping NieAbstract:The Matrix Pencil method (MPM) has been used to reduce the number of elements in the linear antenna array with a Pencil-beam pattern. This work extends the MPM-based synthesis method to the synthesis of shaped-beam patterns by using the forward-backward Matrix Pencil method (FBMPM). The FBMPM-based synthesis method places a necessary restriction on the poles which correspond to element positions, and consequently obtains more accurate synthesis results, particularly for the synthesis of asymmetric patterns. Numerical examples show the effectiveness and advantages of the proposed method in the reduction of the number of elements for shaped-beam patterns.
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reducing the number of elements in a linear antenna array by the Matrix Pencil method
IEEE Transactions on Antennas and Propagation, 2008Co-Authors: Yanhui Liu, Zaiping Nie, Qing Huo LiuAbstract:The synthesis of a nonuniform antenna array with as few elements as possible has considerable practical applications. This paper introduces a new non-iterative method for linear array synthesis based on the Matrix Pencil method (MPM). The method can synthesize a nonuniform linear array with a reduced number of elements, and can be also used to reduce the number of elements for linear arrays designed by other synthesis techniques. In the proposed method, the desired radiation pattern is first sampled to form a discrete pattern data set. Then we organize the discrete data set in a form of Hankel Matrix and perform the singular value decomposition (SVD) of the Matrix. By discarding the non-principal singular values, we obtain an optimal lower-rank approximation of the Hankel Matrix. The lower-rank Matrix actually corresponds to fewer antenna elements. The Matrix Pencil method is then utilized to reconstruct the excitation and location distributions from the approximated Matrix. Numerical examples show the effectiveness and advantages of the proposed synthesis method.
Qing Huo Liu - One of the best experts on this subject based on the ideXlab platform.
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reducing the number of elements in multiple pattern linear arrays by the extended Matrix Pencil methods
IEEE Transactions on Antennas and Propagation, 2014Co-Authors: Yanhui Liu, Qing Huo Liu, Zaiping NieAbstract:Previously, the Matrix Pencil method (MPM) and the forward-backward MPM (FBMPM) were used to effectively reduce the number of antenna elements in the single-pattern linear arrays. This work extends the MPM and FBMPM-based synthesis methods to the synthesis of multiple-pattern linear arrays with a smaller number of elements. The extended MPM (resp., the extended FBMPM) method organizes all the multiple pattern data into a composite Hankel (resp., composite Hankel-Toeplitz) Matrix from which the minimum number of elements and the common poles corresponding to element positions can be obtained with similar processing used in the original MPM or FBMPM synthesis method. In particular, the extended FBMPM inherits the advantage of the original FBMPM that a useful restriction is put on the distribution of poles, which makes the element positions obtained much more accurate and robust. Numerical experiments are conducted to validate the effectiveness and robustness of the proposed methods. For the tested cases, the element saving is about 20% ~ 25% for reconfigurable shaped patterns, and can be even more for electrically large linear arrays with scanned Pencil-beams.
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reducing the number of elements in the synthesis of shaped beam patterns by the forward backward Matrix Pencil method
IEEE Transactions on Antennas and Propagation, 2010Co-Authors: Yanhui Liu, Qing Huo Liu, Zaiping NieAbstract:The Matrix Pencil method (MPM) has been used to reduce the number of elements in the linear antenna array with a Pencil-beam pattern. This work extends the MPM-based synthesis method to the synthesis of shaped-beam patterns by using the forward-backward Matrix Pencil method (FBMPM). The FBMPM-based synthesis method places a necessary restriction on the poles which correspond to element positions, and consequently obtains more accurate synthesis results, particularly for the synthesis of asymmetric patterns. Numerical examples show the effectiveness and advantages of the proposed method in the reduction of the number of elements for shaped-beam patterns.
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reducing the number of elements in a linear antenna array by the Matrix Pencil method
IEEE Transactions on Antennas and Propagation, 2008Co-Authors: Yanhui Liu, Zaiping Nie, Qing Huo LiuAbstract:The synthesis of a nonuniform antenna array with as few elements as possible has considerable practical applications. This paper introduces a new non-iterative method for linear array synthesis based on the Matrix Pencil method (MPM). The method can synthesize a nonuniform linear array with a reduced number of elements, and can be also used to reduce the number of elements for linear arrays designed by other synthesis techniques. In the proposed method, the desired radiation pattern is first sampled to form a discrete pattern data set. Then we organize the discrete data set in a form of Hankel Matrix and perform the singular value decomposition (SVD) of the Matrix. By discarding the non-principal singular values, we obtain an optimal lower-rank approximation of the Hankel Matrix. The lower-rank Matrix actually corresponds to fewer antenna elements. The Matrix Pencil method is then utilized to reconstruct the excitation and location distributions from the approximated Matrix. Numerical examples show the effectiveness and advantages of the proposed synthesis method.
