ELEDIA Student Project Activities and Theses Reports: No conditions. Results ordered -Date Deposited. 2018-02-21T18:40:17ZEPrintshttp://eledia.science.unitn.it/images/eledialogo.pnghttp://eledia.science.unitn.it/publications/7102012018-02-16T10:40:25Z2018-02-16T10:40:25Zhttp://eledia.science.unitn.it/publications/id/eprint/764This item is in the repository with the URL: http://eledia.science.unitn.it/publications/id/eprint/7642018-02-16T10:40:25ZAn Innovative Material-by-Design Method for the Enhancement of Linear Active Electronically-Scanned ArraysThe problem of enhancing the radiation features (in terms of directivity and side-lobe level) of an existing linear active electronically-scanned array (AESA) is addressed. A novel material-by-design (MbD) design technique is proposed to synthesize suitably engineered meta-material lenses able to significantly improve the performance of the covered antenna array without increasing the number of elementary radiators nor re-designing the feeding network. Moreover, the synthesized architectures are able to mimic the radiation characteristics of larger apertures without requiring highly-anisotropic meta-materials thanks to the exploitation of a customized quasi-conformal transformation optics (QCTO) technique in combination with a source inversion (SI) strategy. Some numerical results are presented and discussed in order to verify the potentialities of the proposed synthesis technique.M. SalucciG. OliveriN. AnselmiG. GottardiA. Massa2018-02-09T13:42:40Z2018-02-09T13:42:40Zhttp://eledia.science.unitn.it/publications/id/eprint/762This item is in the repository with the URL: http://eledia.science.unitn.it/publications/id/eprint/7622018-02-09T13:42:40ZQuasi-Conformal Transformation Optics as Applied to Linear Antenna Array Performance EnhancementThis work presents an innovative Material-by-Design (MbD) technique aimed at improving the radiation features of existing linear active electronically-scanned arrays (AESAs). Such a performance enhancement (in terms of beam-width, directivity, and side-lobe level) is guaranteed without increasing the number of elements nor requiring the re-design of the radiators and/or feeding network. Thanks to a suitable customization and integration of the quasi-conformal transformation optics (QCTO) technique approach with a source inversion (SI) strategy, the developed methodology enables the synthesis of meta-material enhancing radomes with reduced complexity (in terms of anisotropy indexes) able to let the original array reproduce the radiation performance of larger target apertures. Some representative numerical results are shown in order to validate the effectiveness of the proposed MbD approach, by taking into account the existing trade-off between the achievable boost and the overall cost in terms of complexity of the QCTO-synthesized meta-materials.M. SalucciG. OliveriN. AnselmiG. GottardiA. Massa2018-02-02T15:37:25Z2018-02-02T15:37:25Zhttp://eledia.science.unitn.it/publications/id/eprint/761This item is in the repository with the URL: http://eledia.science.unitn.it/publications/id/eprint/7612018-02-02T15:37:25ZSynthesis of Metamaterial Enhancing Lenses for Improving the Radiation Performance of Existing Linear Antenna Arrays This work presents an innovative material-by-design (MbD) technique for the improvement of the radiation features (in terms of beam-width, directivity and side-lobe level) of existing linear scanned arrays. The developed strategy exploits a suitably customized quasi conformal transformation optics (QCTO) technique to synthesize meta-material radomes with reduced anisotropy as well as a source inversion (SI) strategy in order to let the original array mimic the radiation performance of significantly larger apertures. Some numerical results are presented ad discussed in order to validate the effectiveness of the MbD approach and its suitability to improve the radiation characteristics of linear arrays.M. SalucciG. OliveriN. AnselmiG. GottardiA. Massa2018-01-26T16:27:24Z2018-01-26T16:27:24Zhttp://eledia.science.unitn.it/publications/id/eprint/760This item is in the repository with the URL: http://eledia.science.unitn.it/publications/id/eprint/7602018-01-26T16:27:24ZPerformance Enhancement of Linear Scanned Arrays through an Innovative Material-by-Design MethodologyA novel quasi conformal transformation optics (QCTO)-based approach is introduced for the synthesis of coating meta-lenses that are able to improve the radiation pattern of the covered linear antenna arrays. Thanks to the QCTO technique, the proposed material-by-design synthesis methodology is able to reduce the half-power beam-width (HPBW) and the side-lobe level (SLL) of a given linear array without introducing strong anisotropies in the synthesized meta-material coating lens. Some representative numerical examples are shown in order to assess the effectiveness, as well as the limits, of the proposed MbD method.
M. SalucciG. OliveriN. AnselmiG. GottardiA. Massa2018-01-19T16:11:14Z2018-01-19T16:11:14Zhttp://eledia.science.unitn.it/publications/id/eprint/759This item is in the repository with the URL: http://eledia.science.unitn.it/publications/id/eprint/7592018-01-19T16:11:14ZA QCTO‐SI Method for the Design of Enhancing Lenses for Linear Antenna ArraysIn this work a novel material-by-design (MbD) strategy is proposed to address the problem of enhancing the radiation performance (in terms of directivity and side-lobe level) of existing linear phased arrays. Thanks to the integration of the quasi-conformal transformation optics (QCTO) technique with a customized source inversion (SI) strategy, the proposed approach enables the synthesis of meta-material lenses with reduced anisotropy indexes that are able to significantly enhance the radiation characteristics of linear antenna arrays, letting them mimic the performance of larger apertures. To prove the effectiveness of the MbD methodology, some numerical benchmarks are reported and discussed.M. SalucciG. OliveriN. AnselmiG. GottardiA. Massa2018-01-13T07:02:20Z2018-01-13T07:02:20Zhttp://eledia.science.unitn.it/publications/id/eprint/758This item is in the repository with the URL: http://eledia.science.unitn.it/publications/id/eprint/7582018-01-13T07:02:20ZMaterial‐by‐Design as applied to Linear Antenna Array Performance ImprovementThis work deals with the problem of improving the radiation performances of linear active electronically scanned arrays (AESAs), without increasing the number of radiating elements nor requiring a re-design of the radiators and/or the feeding network. The problem is addressed by means of an innovative Material-by-Design (MbD) approach based on the quasi-conformal transformation optics (QCTO) technique and a customized source inversion (SI) strategy. The synthesized architectures are composed by a metamaterial lens and a tapered version of the original feeding network, able to match the radiation characteristics of significantly larger apertures. Some preliminary results are reported in order to validate the effectiveness of the proposed MbD approach.M. SalucciG. OliveriN. AnselmiG. GottardiA. Massa2018-01-06T08:39:16Z2018-01-06T08:39:16Zhttp://eledia.science.unitn.it/publications/id/eprint/757This item is in the repository with the URL: http://eledia.science.unitn.it/publications/id/eprint/7572018-01-06T08:39:16ZEnhancement of Linear Antenna Arrays through an Innovative QCTO‐SI Method: Preliminary AssessmentIn this work, an innovative Material-by-Design (MbD) methodology is proposed to improve the radiation features of a linear active electronically-scanned array (AESA) without increasing the number of elements nor requiring the re-design of the radiators and/or feeding network. The quasi-conformal transformation optics (QCTO) approach is exploited to design an enhancing meta-material lens that is able to focus the radiated field of the original antenna. Moreover, a source inversion (SI) strategy is adopted to properly set the array excitations in order to match the radiation characteristics of significantly larger apertures. Some preliminary numerical results are reported and discussed.M. SalucciG. OliveriN. AnselmiG. GottardiA. Massa2017-11-10T15:19:44Z2017-11-10T15:19:45Zhttp://eledia.science.unitn.it/publications/id/eprint/756This item is in the repository with the URL: http://eledia.science.unitn.it/publications/id/eprint/7562017-11-10T15:19:44ZEfficient Tiling of Large Planar Sub‐Arrayed Phased Arrays Through Schemata‐Driven Evolutionary OptimizationIn this work, the synthesis of large clustered arrays - computationally unaffordable through standard stochastic global optimization techniques - is addressed through an innovative schemata-driven approach. The proposed design methodology is based on the analytic definition of a set of reference tiling arrangements and a customized genetic algorithm (GA)-based strategy which is able to effectively and efficiently explore the solution space of the complete tiling configurations. Some representative numerical experiments are presented in order to verify the effectiveness of the developed synthesis technique for the tiling of large planar phased sub-arrays providing optimal side-lobe level (SLL) radiation performance.N. AnselmiP. RoccaM. SalucciA. Massa2017-11-03T14:36:46Z2017-11-03T14:36:46Zhttp://eledia.science.unitn.it/publications/id/eprint/755This item is in the repository with the URL: http://eledia.science.unitn.it/publications/id/eprint/7552017-11-03T14:36:46ZAn Innovative GA‐Based Synthesis Method for the Design of Small‐Sized Tiled Planar Sub‐Arrayed Phased ArraysIn this work, an innovative methodology for the design of planar sub-arrayed phased arrays composed by irregular arrangements of vertical and horizontal domino-shaped tiles is presented. More precisely, the proposed design method is aimed at optimally synthesizing low and medium size arrays through a suitable customization of mathematical tiling theorems and algorithms. Thanks to the exploitation of a customized genetic algorithm (GA)-based optimization strategy, the retrieval of the global optimal solution for the problem of finding the complete tiling affording the minimum side-lobe level (SLL) is effectively yielded through the proposed approach. A set of numerical benchmarks is presented in order to assess the proposed sub-arraying technique for small-sized problems.N. AnselmiP. RoccaM. SalucciA. Massa2017-10-27T15:04:23Z2017-10-27T15:04:23Zhttp://eledia.science.unitn.it/publications/id/eprint/754This item is in the repository with the URL: http://eledia.science.unitn.it/publications/id/eprint/7542017-10-27T15:04:23ZDesign of Planar Sub‐Arrayed Phased Arrays Through Irregular Domino‐Shaped TilesIn this work, the design of planar sub-arrayed phased arrays through irregular domino-shaped tiles is presented. An innovative enumerative approach is exploited to synthesize the optimal clustering in order to obtain the maximum aperture coverage and radiation performance. Moreover, a design procedure based on optimal tiling theorems drawn from mathematical theory and exploiting a customized genetic algorithm (GA) optimizer to effectively minimize a suitably defined cost function is proposed. Some preliminary numerical results are presented in order to assess the potentialities of the proposed synthesis methods for small-sized arrays.N. AnselmiP. RoccaM. SalucciA. Massa2017-10-16T07:31:11Z2017-10-16T07:31:11Zhttp://eledia.science.unitn.it/publications/id/eprint/753This item is in the repository with the URL: http://eledia.science.unitn.it/publications/id/eprint/7532017-10-16T07:31:11ZSynthesis of Wideband WAIMs within the System‐by‐Design FrameworkIn this work, the design of wideband wide-angle impedance matching (WAIM) structures is proposed for waveguide-fed planar phased arrays. An innovative System-by-Design (SbD) approach is exploited to determine the geometrical descriptors of the WAIM, which is composed by a metasurface of regularly-arranged microstrip printed unit cells. The proposed solution technique is based on the combination of elementary functional blocks aimed at (i) exploring the search space, (ii) analyzing the resulting metasurface structure to deduce the equivalent permittivity/permeability tensors, (iii) computing the phased array response, and (iv) linking the obtained result with the problem constraints and objectives to determine the associated cost function. Some numerical results are shown in order to assess the effectiveness of the SbD-based design strategy.G. OliveriM. SalucciN. AnselmiA. Massa2017-10-09T07:57:30Z2017-10-09T07:57:30Zhttp://eledia.science.unitn.it/publications/id/eprint/752This item is in the repository with the URL: http://eledia.science.unitn.it/publications/id/eprint/7522017-10-09T07:57:30ZParticle Swarm Optimization of Innovative Wide Angle Impedance Matching MetasurfacesThe design of innovative wide-angle impedance matching (WAIM) structures is proposed to mitigate reflection issues arising when scanning waveguide-fed planar phased arrays. The WAIM is based on a metasurface which is composed by several unit cells arranged according to a triangular lattice. A System-by-Design (SbD) approach is exploited to synthesize - by means of a customized particle swarm optimization (PSO)-based algorithm - the geometrical descriptors of such a metasurface in order to reduce the reflections when steering the main beam of the array. Numerical results are shown in order to verify the effectiveness as well as the potentialities of the developed design strategy.G. OliveriM. SalucciN. AnselmiA. Massa2017-10-02T08:11:43Z2017-10-02T08:11:43Zhttp://eledia.science.unitn.it/publications/id/eprint/749This item is in the repository with the URL: http://eledia.science.unitn.it/publications/id/eprint/7492017-10-02T08:11:43ZInnovative Design of Metamaterial Printed WAIMs through a System-by-Design ApproachAn innovative approach is proposed for the synthesis of WAIM structures able to compensate the inter‐element coupling effects limiting the maximum scanning angles of active electronically‐scanned arrays (AESAs). The WAIM is composed by a metasurface represented by a regular grid of microstrip printed unit cells organized according to an hexagonal lattice. Accordingly, the geometrical descriptors of the unit cells are synthesized through a System‐by‐Design (SbD) approach aimed at minimizing the antenna input reflections caused by impedance mismatching when the array is steered. Some numerical results are shown in order to assess the effectiveness of the proposed design methodology.G. OliveriM. SalucciN. AnselmiA. Massa2017-09-22T15:04:34Z2017-09-22T15:04:34Zhttp://eledia.science.unitn.it/publications/id/eprint/748This item is in the repository with the URL: http://eledia.science.unitn.it/publications/id/eprint/7482017-09-22T15:04:34ZA System‐by‐Design Approach for the Synthesis of WAIMs for Planar ArraysIn this work, wide-angle impedance matching (WAIM) layers based on metasurfaces are designed to enhance the radiation efficiency of planar phased arrays. Toward this end, a System-by-Design (SbD) approach is adopted where the layer geometrical features are the solution descriptors, while the minimization of the array power reflection is the synthesis objective. Selected numerical examples are shown to illustrate the potentialities of the proposed SbD-based design strategy.G. OliveriM. SalucciN. AnselmiA. Massa2017-09-15T11:56:56Z2017-09-15T11:56:56Zhttp://eledia.science.unitn.it/publications/id/eprint/747This item is in the repository with the URL: http://eledia.science.unitn.it/publications/id/eprint/7472017-09-15T11:56:56ZInnovative Synthesis of WAIM Layers for Waveguide‐Fed Planar Phased ArraysThis work deals with the design of wide-angle impedance matching (WAIM) layers aimed at mitigating reflection issues arising in waveguide-fed planar phased arrays. The synthesis problem is formulated within the System-by-Design (SbD) framework, by minimizing the antenna input reflections caused by impedance mismatching when the array is steered through the optimization of the geometrical descriptors of the WAIM unit cells. Some numerical results are shown in order to assess the effectiveness of the proposed synthesis strategy.G. OliveriM. SalucciN. AnselmiA. Massa2017-09-08T14:26:08Z2017-09-08T14:26:08Zhttp://eledia.science.unitn.it/publications/id/eprint/746This item is in the repository with the URL: http://eledia.science.unitn.it/publications/id/eprint/7462017-09-08T14:26:08ZSystem‐by‐Design Synthesis of Wide Angle Impedance Matching LayersIn this work, the synthesis of metasurface-based wide-angle impedance matching (WAIM) layers is proposed. The designed structures allow to mitigate reflection issues in waveguide-fed planar phased arrays. To achieve such a goal, the synthesis problem is formulated in the System-by-Design (SbD) framework, and the degrees of freedom are represented by the geometrical descriptors of the metasurface unit cells. The final layout is then obtained by minimizing the antenna input reflections caused by impedance mismatching when the array is steered. A preliminary numerical validation is provided in order to assess the effectiveness and flexibility of the proposed SbD-based design approach.G. OliveriM. SalucciN. AnselmiA. Massa2017-08-23T14:52:46Z2017-08-23T14:52:46Zhttp://eledia.science.unitn.it/publications/id/eprint/745This item is in the repository with the URL: http://eledia.science.unitn.it/publications/id/eprint/7452017-08-23T14:52:46ZDictionary‐Based Bayesian Compressive Sensing for Imaging Arbitrary ScatterersThis work deals with an innovative free-space inverse scattering technique. The developed methodology is based on the exploitation of a Bayesian Compressive Sensing (BCS) solver and a set (or dictionary) of expansion bases. Several BCS-regularized reconstructions are performed using the different bases in the dictionary, and the sparsest solution is selected as the most reliable one. Thanks to such an approach, (i) no a-priori information about the unknown scatterers is required, and (ii) it is possible to extend the range of applicability of standard BCS-based inversion to objects having arbitrary size and shape. In order to verify the effectiveness of the proposed technique, as well as to test its robustness to noise, some illustrative numerical results are shown in the following. N. AnselmiG. OliveriM. HannanM. SalucciA. Massa2017-08-14T12:40:26Z2017-08-14T12:40:26Zhttp://eledia.science.unitn.it/publications/id/eprint/744This item is in the repository with the URL: http://eledia.science.unitn.it/publications/id/eprint/7442017-08-14T12:40:26ZAn Innovative BCS‐Based Microwave Imaging Technique for Imaging Unknown Objects With Arbitrary Size and ShapeThis work presents a numerical validation of an innovative two-dimensional (2D) microwave inverse scattering technique exploiting Bayesian Compressive Sensing (BCS) and a dictionary of wavelet-based expansion bases. The goal of the dictionary-based BCS is to provide faithful guesses of the dielectric distribution inside the imaged scenario even if the unknown objects inside it are not sparse in the standard pixel basis. The developed strategy is based on a two-level hierarchical application of the BCS algorithm. In the first step, several sparsity-regularized inversions are performed using the dictionary of candidate bases. In the second step, the retrieved vectors are compared and the sparsest reconstruction is selected. Some numerical results are shown, in order to verify the effectiveness of the developed microwave imaging technique. Moreover, some illustrative results are shown to compare its performance with respect to competitive state-of-the-art alternatives.N. AnselmiG. OliveriM. HannanM. SalucciA. Massa2017-08-04T15:19:45Z2017-08-04T15:19:45Zhttp://eledia.science.unitn.it/publications/id/eprint/743This item is in the repository with the URL: http://eledia.science.unitn.it/publications/id/eprint/7432017-08-04T15:19:45ZExtending the Applicability Range of Compressive Sensing‐Based Microwave Imaging to Arbitrary Scatterers This work deals with an innovative two-dimensional (2D) free-space microwave imaging technique. The developed inverse scattering (IS) technique is aimed at enabling Compressive Sensing (CS) to deal with the retrieval of unknown scatterers which are not necessarily sparse in the standard sense, i.e., in the pixel domain. Accordingly, the proposed technique exploits a user-defined dictionary of expansion bases that are used to retrieve several guesses of the electromagnetic properties of the investigation domain. Then, following the BCS paradigm, the sparsest solution is recognized as the optimal one. Some numerical results are presented, in order to verify the effectiveness of the proposed IS technique for imaging scatterers with arbitrary size and shape.N. AnselmiG. OliveriM. HannanM. SalucciA. Massa2017-07-28T15:46:06Z2017-07-28T15:46:06Zhttp://eledia.science.unitn.it/publications/id/eprint/742This item is in the repository with the URL: http://eledia.science.unitn.it/publications/id/eprint/7422017-07-28T15:46:06ZInnovative Alphabet‐Based Bayesian Compressive Sensing Technique for Imaging Targets with Arbitrary ShapeIn this work an innovative two-dimensional (2D) microwave imaging technique exploiting Bayesian Compressive Sensing (BCS) and a wavelet-based alphabet for representing the problem unknowns is dealt with. The proposed approach is based on the generalization of the sparsity concept, extending the range of applicability of BCS-based inverse scattering (IS) techniques to objects with arbitrary shape and dimensions. A set of BCS reconstructions is performed considering different expansion bases in the alphabet, without the need for a-priori knowledge about the unknown scatterers. Then, the best reconstruction is recognized as that minimizing the number of non-null retrieved coefficients (i.e., the sparsest one). In order to verify the effectiveness of the proposed imaging technique, a set of representative numerical benchmarks is presented. Some comparisons with state-of-the-art IS techniques are presented, as well.N. AnselmiG. OliveriM. HannanM. SalucciA. Massa