@article {15_TAP_RubioIzqdoCorcoles_ModalNetworkMIMO, title = {Mutual Coupling Compensation Matrices for Transmitting and Receiving Arrays}, journal = {IEEE Transactions on Antennas and Propagation}, volume = {63}, number = {2}, year = {2015}, month = {Feb}, pages = {839-843}, abstract = {A general method to obtain a matrix which allows the compensation of mutual coupling effects in transmitting arrays for the total field in all directions is introduced. This method is independent of the numerical method used in the analysis and it can include the effect of the antenna platform. The starting point can be the active element patterns or the spherical mode expansion from spherical near-field antenna measurements. Additionally, the spherical mode expansion is also used to find a matrix which allows the compensation of mutual coupling effects in receiving arrays. Through this theory, a simple relation between the compensation matrices of the transmitting and the receiving arrays is found. As a consequence, the scattering matrix of a circuit that allows the simultaneous compensation of mutual coupling effects for the transmission and the reception problem can be easily defined. Finally, it will be shown how the capabilities of the compensation in all directions depend strongly on the array element.}, keywords = {Active element pattern, antenna array, Antenna arrays, Antenna measurements, antenna radiation patterns, finite element analysis, Mutual coupling, mutual coupling compensation, spherical mode expansion, transmitting antennas, Vectors}, issn = {0018-926X}, doi = {10.1109/TAP.2014.2382691}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=6987253}, author = {Rubio, J and Izquierdo, J F and J C{\'o}rcoles} } @conference {14_URSIESP_Corcoles_SintesisdeFourier, title = {Matriz de compensaci{\'o}n de acoplos mutuos para agrupaciones de antenas en problemas de radiaci{\'o}n}, booktitle = {Proc. 2014 Simposium Nacional URSI (in Spanish)}, year = {2014}, month = {Sep}, pages = {1-4}, abstract = {In this work, a general method to obtain a matrix which allows compensating the mutual coupling effects in arrays for the total field in all directions is introduced. This method is independent of the numerical method used in the analysis and it can include the effect of the antenna platform. The starting point can be the active element patterns or spherical near-field antenna measurements. It will be shown how the capabilities of compensation depend strongly on the array element.}, author = {Rubio, J and Izquierdo, J F and J C{\'o}rcoles} } @conference {13_EIEC_RubioetAl_SphericalModesinCEM, title = {Spherical Modes in Computational Electromagnetics applied to Antenna Problems}, booktitle = {IX Iberian Meeting on Computational Electromagnetism}, year = {2013}, month = {May}, pages = {1}, abstract = {In this work we review the use of spherical modes in computational electromagnetics mainly applied to antenna problems. First, the theory of spherical modes will be reviewed. Second, the use jointly with the Finite Element Method will be exposed. Third, the application to the analysis of finite arrays will be shown. Finally, it will be presented how the spherical modes allow us to obtain an equivalent model of the antenna, in terms of infinitesimal dipoles, which increases the capabilities of the method for the analysis of finite arrays.}, author = {Rubio, J and Izquierdo, J F and Gonz{\'a}lez, M A and Gil, J M and Garc{\'\i}a, J and de la Rubia, V and J C{\'o}rcoles and Zapata, J} } @article {11_TAP_CorcolesRubio_SphericalSynthesis, title = {Spherical-Wave-Based Shaped-Beam Field Synthesis for Planar Arrays Including the Mutual Coupling Effects}, journal = {IEEE Transactions on Antennas and Propagation}, volume = {59}, number = {8}, year = {2011}, month = {Aug}, pages = {2872-2881}, abstract = {An analytical method to synthesize shaped-beam patterns with planar arrays, based on the handling of spherical waves, is proposed. Translational Addition Theorems will be used here for two different purposes: (1) relating the spherical modes produced by each element in the array to calculate the mutual coupling effects, and (2) expressing the field radiated by each element in terms of spherical modes corresponding to the whole array, to carry out a spherical-wave synthesis procedure based on the orthogonal properties of spherical modes. This field synthesis method is based on the fact that any antenna radiated field can be expressed as a discrete series of weighted spherical vector wave functions and it only requires the a priori knowledge of the Generalized Scattering Matrix of each array element considered as isolated from the rest of the array elements.}, keywords = {antenna feeds, antenna radiated field, antenna radiation patterns, Arrays, electromagnetic coupling, electromagnetic wave scattering, field synthesis method, generalized scattering matrix, GSM, Mutual coupling, mutual coupling effect, pattern field synthesis, planar antenna arrays, planar array, planar array element, Planar arrays, S-matrix theory, Scattering, spherical wave expansion, spherical-wave synthesis procedure, spherical-wave-based shaped-beam field synthesis, translational addition theorem, translational addition theorems, weighted spherical vector wave function}, issn = {0018-926X}, doi = {10.1109/TAP.2011.2158950}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=5871276}, author = {J C{\'o}rcoles and Rubio, J and Gonz{\'a}lez, M A} } @conference {10_EIEC_RubioCorcoles_SintesisAnaliticaModosEsfericos, title = {S{\'\i}ntesis anal{\'\i}tica de agrupaciones planas basada en traslaci{\'o}n de modos esf{\'e}ricos}, booktitle = {VII Iberian Meeting on Computational Electromagnetism (in Spanish)}, year = {2010}, month = {May}, pages = {1}, abstract = {Se presenta en este trabajo un m{\'e}todo anal{\'\i}tico de s{\'\i}ntesis de haz conformado en agrupaciones planas basado en la manipulaci{\'o}n de modos esf{\'e}ricos. Los teoremas de traslaci{\'o}n se utilizan para dos fines diferentes: relacionar los modos esf{\'e}ricos de cada elemento de la agrupaci{\'o}n con el fin de calcular los efectos de acoplamiento mutuo, y expresar el campo producido por cada elemento en t{\'e}rminos de modos esf{\'e}ricos de todo el conjunto para aplicar un procedimiento de s{\'\i}ntesis esf{\'e}rica basada en las propiedades ortogonales de los modos esf{\'e}ricos. Este m{\'e}todo de s{\'\i}ntesis de campo se basa en el hecho de que cualquier campo radiado de la antena puede expresarse como una serie discreta ponderada de funciones vectoriales esf{\'e}ricas y s{\'o}lo requiere el conocimiento a priori de la matriz de dispersi{\'o}n generalizada de cada elemento de la agrupaci{\'o}n considerado aislado del resto.}, author = {Rubio, J and 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_AWPL_RubioCorcoles_InclusionFeedingNetwork, title = {Inclusion of the Feeding Network Effects in the Generalized-Scattering-Matrix Formulation of a Finite Array}, journal = {IEEE Antennas and Wireless Propagation Letters}, volume = {8}, year = {2009}, pages = {819-822}, abstract = {The formulation of the generalized scattering matrix (GSM) of a finite array is revised to take into account the feeding network effects in the calculation of the external mutual coupling. It allows the analysis of finite arrays of externally coupled elements whose radiated field can be described by means of spherical waves on a ground plane, such as apertures, monopoles, cavity-backed patch antennas, or dielectric resonator antennas (DRAs), including rigorously the mismatching and internal coupling effects because of the feeding network.}, keywords = {antenna feeds, antenna radiation pattern, antenna radiation patterns, aperture antenna, cavity-backed patch antenna, dielectric resonator antenna, dielectric resonator antennas, DRA, electromagnetic coupling, entire-domain basis function, Entire-domain basis functions, external mutual coupling, feeding network effect, finite array, generalized scattering matrix (GSM), generalized scattering matrix formulation, GSM, internal coupling effect, mismatching effect, monopole antenna, multiport networks, Mutual coupling, S-matrix theory, spherical wave, spherical wave expansion, waveguide antenna arrays, waveguide-fed array}, issn = {1536-1225}, doi = {10.1109/LAWP.2009.2026715}, url = {http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=\&arnumber=5159466}, author = {Rubio, J and J C{\'o}rcoles and Gonzalez de Aza, 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} } @article {09_IntJRFMiCAE_CORCOLES_PerformanceUslot, title = {Performance characterization of wideband, wide-angle scan arrays of cavity-backed U-slot microstrip patch antennas}, journal = {International Journal of RF and Microwave Computer-Aided Engineering}, volume = {19}, number = {3}, year = {2009}, pages = {389{\textendash}396}, abstract = {This work looks at the use of wideband cavity-backed U-slot microstrip antennas in finite phased arrays. This configuration retains the single-patch and single-layer characteristics of conventional microstrip antenna arrays and provides a good impedance matching over wider scan angles when electrically thick substrates are used to improve the frequency bandwidth. The characteristics of finite phased arrays of U-slot rectangular microstrip patches enclosed in cylindrical cavities are analyzed from a validated hybrid methodology based on the finite element method, the modal analysis, and the properties of spherical waves. The results are compared with those obtained using an infinite array model. {\textcopyright} 2008 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.}, keywords = {broadband U-slot patch antenna, cavity-backed microstrip antennas, finite element method, finite phased array, spherical mode expansion}, issn = {1099-047X}, doi = {10.1002/mmce.20361}, url = {http://dx.doi.org/10.1002/mmce.20361}, author = {J C{\'o}rcoles and Gonz{\'a}lez, M A and Rubio, J and Zapata, J} } @conference {09_URSIESP_Corcoles_SintesisdeFourier, title = {S{\'\i}ntesis de Fourier para agrupaciones lineales de antenas reales y acopladas}, booktitle = {Proc. 2009 Simposium Nacional URSI (in Spanish)}, year = {2009}, month = {Sep}, pages = {1-4}, abstract = {This work presents a novel and simple pattern synthesis procedure for lineal and equispaced arrays that considers real individual antenna elements{\textquoteright} patterns and includes the mutual coupling between elements. It is an extension of the classic design techniques of the Fourier series method or the Woodward-Lawson frequency sampling method based on the expansion of the radiated field of the individual array elements in spherical modes, and the characterization of the whole array from a generalized scattering matrix}, author = {J C{\'o}rcoles and Gonz{\'a}lez, M A and Rubio, J} } @conference {08_EIEC_CorcolesetAl_OptimizationIPM, title = {Optimization of coupled antenna arrays characterized by spherical modes by means of an interior-point filtering method}, booktitle = {VI Iberian Meeting on Computational Electromagnetism}, year = {2008}, month = {Oct}, pages = {1}, abstract = {In this work, we present a novel method for the efficient optimization of arbitrary planar array excitations. This method, which inherently takes into account every array element pattern as well as all interelement couplings, allows the maximization of the directive or power gain of an arbitrary planar array scanned at whichever direction, subject to constraints on the maximum sidelobe level, the maximum crosspolar level, the minimum aperture illumination efficiency, the setting of null pointing directions or a dynamic range ratio control. Numerical examples of arrays with canonical geometries, composed of microstrip patches or dielectric resonator antennas and covering a wide variety of requirements are presented.}, author = {J C{\'o}rcoles and Gonz{\'a}lez, M A and Rubio, J and Zapata, J} }