@article {12_TAP_Corcoles_CombinedArrayThinning, title = {Efficient Combined Array Thinning and Weighting for Pattern Synthesis With a Nested Optimization Scheme}, journal = {IEEE Transactions on Antennas and Propagation}, volume = {60}, number = {11}, year = {2012}, month = {Nov}, pages = {5107-5117}, abstract = {A novel procedure to thin an antenna array which synthesizes a desired pattern with the minimum number of active elements is introduced. The proposed method yields both the active elements and their corresponding excitations of a thinned array having the minimum number of active elements needed to meet several prescribed design specifications of the radiated far-field pattern. Specifications such as achieving a minimum gain, obtaining a pattern with a maximum allowable sidelobe level or synthesizing a shaped beam pattern confined into a mask are considered. Null field directions can also be added. In order to carry out the thinning, a genetic algorithm is used, while computing the excitations is carried out through linear or quadratic programming. The procedure incorporates the generalized scattering matrix analysis of an array made up of elements whose radiated field can be expressed as a spherical mode expansion, thus taking all electromagnetic effects inherently into account. Therefore, since the presence of an element can substantially alter the array features because of mutual coupling, two types of thinning are considered: removing elements or turning them off. Numerical results of arrays made up of isotropic sources, dielectric resonator antennas and microstrip patch antennas are presented.}, keywords = {Antenna arrays, Arrays, generalized scattering matrix, Genetic algorithms, genetic algorithms (GAs), GSM, linear programming, optimization, quadratic programming (QP), spherical wave expansion, thinned arrays, Transmission line matrix methods, Vectors}, issn = {0018-926X}, doi = {10.1109/TAP.2012.2207667}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=6236035}, author = {J C{\'o}rcoles and Gonz{\'a}lez, M A} } @conference {09_EuCAP_Corcoles, title = {Array design for different SLL and null directions with an interior-point optimization method from the generalized-scattering-matrix and spherical modes}, booktitle = {Antennas and Propagation, 2009. EuCAP 2009. 3rd European Conference on}, year = {2009}, month = {March}, pages = {1381-1385}, abstract = {This paper presents a pattern synthesis technique for arbitrary planar arrays which can be characterized in terms of a generalized-scattering-matrix (GSM) and whose radiated field can be expressed as a spherical mode expansion (SME). The procedure yields the complex-valued excitations needed to achieve a pattern which fulfils the requirements of different sidelobe levels in different regions and several prescribed field nulls with a maximum directive gain. The formulation is based on matrix-valued functions which are computed from the GSM and the SME, so all interelement coupling effects coming from complex radiating structures used as array elements are inherently taken into account. To solve the resulting nonlinear optimization problem, a primal-dual interior-point filtering method specifically adapted to this formulation is developed. Numerical results are presented for arrays of microstrip patch antennas and dielectric resonator antennas.}, keywords = {antenna pattern, antenna radiation patterns, antenna sidelobe level, dielectric resonator antenna, dielectric resonator antennas, electromagnetic coupling, Filtering, filtering theory, generalized scattering matrix, generalized-scattering-matrix, GSM, Hessian matrices, interelement coupling effect, interior-point optimization method, Jacobian matrices, microstrip antenna arrays, Microstrip antennas, microstrip patch antenna, Microstrip resonators, nonlinear optimization, optimisation, Optimization methods, pattern synthesis technique, planar antenna array, planar antenna arrays, Planar arrays, primal-dual interior-point filtering method, Resonator filters, S-matrix theory, spherical, spherical mode expansion, Transmission line matrix methods, wave expansion}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=5067872}, author = {J C{\'o}rcoles and Gonz{\'a}lez, M A and Rubio, J and Zapata, J} } @article {09_TAP_Corcoles_FourierSynthesis, title = {Fourier Synthesis of Linear Arrays Based on the Generalized Scattering Matrix and Spherical Modes}, journal = {IEEE Transactions on Antennas and Propagation}, volume = {57}, number = {7}, year = {2009}, month = {July}, pages = {1944-1951}, abstract = {This paper presents a novel, simple pattern synthesis procedure for linear equispaced arrays which can be characterized by a generalized scattering matrix (GSM) and whose radiated field can be expressed as a weighted sum of shifted spherical waves. It can be viewed as an extension of the classic design techniques of the Fourier series (FS) method or the Woodward-Lawson frequency sampling method, to the case in which the individual antenna elements{\textquoteright} patterns and all interelement couplings are taken into account. The design procedure, which yields the excitations needed to achieve the desired pattern, is based on either the FS or the discrete Fourier transform (DFT) of the spherical mode expansion of the array radiated field, as well as on various properties associated to the FS or DFT coefficients. In this work, to compute the GSM of the array and the spherical mode expansion of the field, a validated hybrid full-wave methodology, based on the finite element method and rotation and translation properties of spherical waves, is used. Numerical results of different synthesized array patterns are presented for different arrays made up of dielectric resonator antennas and cavity-backed microstrip circular patches.}, keywords = {Antenna array mutual coupling, cavity-backed microstrip circular patches, dielectric resonator antennas, discrete Fourier transform, discrete Fourier transforms, discrete Fourier transforms (DFT), finite element analysis, finite element method, finite element methods, Fourier series, Fourier synthesis, Frequency, generalized scattering matrix, GSM, interelement couplings, linear antenna arrays, linear arrays, linear equispaced arrays, microstrip antenna arrays, Microstrip antennas, pattern synthesis, S-matrix theory, Sampling methods, Scattering, scattering matrices, shifted spherical waves, signal sampling, spherical mode expansion, spherical modes, Transmission line matrix methods, Woodward-Lawson frequency sampling}, issn = {0018-926X}, doi = {10.1109/TAP.2009.2021929}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=4907114}, author = {J C{\'o}rcoles and Gonz{\'a}lez, M A and Rubio, J} } @article {09_TAP_Corcoles_MultiobjectiveOptimization, title = {Multiobjective Optimization of Real and Coupled Antenna Array Excitations via Primal-Dual, Interior Point Filter Method From Spherical Mode Expansions}, journal = {IEEE Transactions on Antennas and Propagation}, volume = {57}, number = {1}, year = {2009}, month = {Jan}, pages = {110-121}, keywords = {antenna array, Antenna arrays, Apertures, dielectric resonator antennas, Filters, generalized scattering matrix, Hessian matrices, Jacobian matrices, Lighting, matrix-valued functions, maximum crosspolar level, microstrip antenna arrays, Microstrip antennas, microstrip patch array, minimum aperture illumination efficiency, multiobjective optimization, optimisation, Optimization methods, planar antenna arrays, planar array excitations, Planar arrays, primal-dual interior point method, spherical mode expansions, spherical wave expansion, Transmission line matrix methods}, issn = {0018-926X}, doi = {10.1109/TAP.2008.2009727}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=4797974}, author = {J C{\'o}rcoles and Gonz{\'a}lez, M A and Rubio, J} }