@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} } @article {09_ELL_Corcoles_LPfromGSM, title = {Linear programming from generalised scattering matrix analysis of array for minimum sidelobe level and prescribed nulls}, journal = {Electronics Letters}, volume = {45}, number = {1}, year = {2009}, month = {January}, pages = {9-10}, abstract = {A pattern synthesis technique for arbitrary planar arrays which are characterised in terms of a generalised scattering matrix and whose radiated field is expressed as a spherical mode expansion is introduced. The procedure yields the complex-valued excitations to achieve a minimum-maximum sidelobe level given a specified pointing direction and mainlobe width, as well as prescribed field nulls. All inter-element coupling effects coming from complex radiating structures used as array elements are inherently taken into account. Numerical results are presented for arrays of dielectric resonator antennas.}, keywords = {Antenna arrays, arbitrary planar arrays, complex-valued excitations, dielectric resonator antennas, dielectric resonators, electromagnetic coupling, electromagnetic wave scattering, generalised scattering matrix analysis, inter-element coupling effects, linear programming, minimum sidelobe level array, minimum-maximum sidelobe level, pattern synthesis technique, prescribed nulls}, issn = {0013-5194}, doi = {10.1049/el:20092008}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=4733076}, author = {J C{\'o}rcoles and Gonz{\'a}lez, M A and Zapata, J} } @conference {09_APS_Corcoles_MultibeamLP, title = {Multibeam synthesis with minimum SLL through linear programming from the GSM-analysis of an array}, booktitle = {Antennas and Propagation Society International Symposium, 2009. APSURSI {\textquoteright}09. IEEE}, year = {2009}, month = {June}, pages = {1-4}, abstract = {The application of all sort of optimization techniques to different array pattern synthesis problems has been widely studied since the early days of antenna array design. Most of these works (generally having constraints on the array configuration) take for granted several assumptions, among which one can highlight considering isotropic sources and not taking into account coupling between array elements. Great advances have been achieved in the field of computational electromagnetics which allow complex radiating structures, including finite antenna arrays, to be analyzed from a full-wave approach inherently taking into account all electromagnetic effects. Recently, new techniques for the afore-mentioned pattern synthesis problems with the inclusion of this rigourous electromagentic (EM) analysis have been developed. In this work, the authors propose an EM-based design technique which yields the excitations of an arbitraty planar array to output a field pattern with minimum maximum sidelobe level (SLL) given the directions of various main beams with specified mainlobe widths and different relative amplitudes and phase differences. The array is characterized through a generalized scattering matrix (GSM) and its radiated field is expressed as a spherical mode expansion (SME). The accurate determination of the array GSM is needed to have it rigourously characterized, so the use of a full-wave technique is required in case complex antenna elements or arbitrary array configurations are considered. We develop the formulation to arrive at a standard linear programming (LP) problem. Numerical results of a linear array of dielectric resonator antennas (DRA{\textquoteright}s) are presented.}, keywords = {Antenna arrays, array pattern synthesis, complex radiating structures, computational electromagnetics, Design optimization, dielectric resonator antennas, electromagentic analysis, Electromagnetic analysis, electromagnetic fields, Electromagnetic radiation, electromagnetic waves, generalized scattering matrix, GSM, linear antenna arrays, linear programming, minimum maximum sidelobe level, multibeam antennas, multibeam synthesis, optimization, S-matrix theory, SME, spherical mode expansion}, issn = {1522-3965}, doi = {10.1109/APS.2009.5171513}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=5171513}, author = {J C{\'o}rcoles and Gonz{\'a}lez, M A} }