@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 {11_TAP_PontesCorcoles_ModalNetworkMIMO, title = {Modal Network Model for MIMO Antenna in-System Optimization}, journal = {IEEE Transactions on Antennas and Propagation}, volume = {59}, number = {2}, year = {2011}, month = {Feb}, pages = {643-653}, abstract = {The analysis of MIMO systems is described with the aid of a novel modal network model. For this purpose the capacity performance of typical base station and mobile station antennas in a simulated macro-cellular scenario with varying antenna inter element spacings and antenna rotation will be studied. The model is based on the modal description of typical receiving and transmitting antennas. In this manner a significant simulation time reduction is achieved which allows for faster analysis and optimization. To prove this the effects of both the mobile and base station antennas are investigated. Moreover, for the more restrictive case of base station antennas, a fully modal descriptive model is proven to yield very similar results as those from measured commercial antennas. It is found that the modal approach improves simulation speed without loss of accuracy or generality. Simulations are done for the city of Karlsruhe with a three-dimensional Ray-tracing tool.}, keywords = {3D Ray-tracing tool, Antenna arrays, antenna inter element spacing, antenna optimization, antenna rotation, base station antenna, capacity performance, cellular radio, macro-cellular scenario, MIMO antenna, MIMO communication, MIMO network model, MIMO system, mobile antennas, mobile station antenna, modal network model, multiple-input multiple-output (MIMO), network theory, path-based channel models, receiving antenna, receiving antennas, spherical mode expansion, system optimization, transmitting antenna, transmitting antennas}, issn = {0018-926X}, doi = {10.1109/TAP.2010.2096179}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=5654566}, author = {Pontes, J and J C{\'o}rcoles and Gonz{\'a}lez, M A and Zwick, T} } @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} } @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} } @article {09_AWPL_Corcoles_MutualCouplingCompensation, title = {Mutual Coupling Compensation in Arrays Using a Spherical Wave Expansion of the Radiated Field}, journal = {IEEE Antennas and Wireless Propagation Letters}, volume = {8}, year = {2009}, pages = {108-111}, abstract = {This letter presents a flexible method to compensate the interelement mutual coupling (MC) effects that may degrade the field pattern of an array of real and coupled antennas. A closed-expression for a mutual coupling compensation matrix (MCCM) is derived. The MCCM is used to compensate the presence of the real individual elements{\textquoteright} patterns and the interelement MC effects for any excitations obtained with an isotropic-based pattern synthesis method. The MCCM is calculated from the generalized scattering matrix (GSM) of an antenna array and the spherical mode expansion (SME) of its radiated field. For a given array, this MCCM has to be calculated only once since it only depends on the radiating and scattering characteristics of the antenna elements as well as on their location in the array. Conditions regarding null field pattern directions can also be reinforced in the MCCM. To compute the GSM of the array and the SME of the radiated field, a validated full-wave hybrid and modular methodology is used. Numerical results of synthesized patterns where the MC effects have been compensated are presented for arrays made up of dielectric resonator antennas.}, keywords = {antenna array, Antenna array mutual coupling, Antenna arrays, antenna radiation patterns, dielectric resonator antennas, electromagnetic coupling, field pattern, field radiation, generalized scattering matrix, interelement mutual coupling effect, isotropic-based pattern synthesis method, modular methodology, mutual coupling compensation matrix, Planar arrays, quadratic programming, S-matrix theory, scattering matrices, spherical wave expansion}, issn = {1536-1225}, doi = {10.1109/LAWP.2008.2012276}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=4745777}, author = {J C{\'o}rcoles and Gonz{\'a}lez, M A and Rubio, J} }