arXiv subjects

Andrea Massa

Publications and source records attributed to Andrea Massa.

At least 19 recordsLinked to original sources

arXiv2025

Sensitivity Analysis for Antenna Devices through Interval Arithmetic -- A Generalized Approach

This paper presents a novel method for the sensitivity analysis of electromagnetic (EM) systems whose transfer function (TF), that is the input-output (I/O) relationship between the input parameters affected by tolerance and the system response (i.e., the arising EM performance of interest), is not available in closed (or explicit) form. The method is a generalized analytic technique based on the Interval Analysis (IA). First, an analytic surrogate model (SM) of the TF is defined by means of a learning-by-example (LBE) approach starting from a set of available I/O examples. Then, the LBE-derived SM is extended to intervals through IA to yield inclusive, yet finite, performance bounds of the output system response when the control parameters are affected by unknown, but bounded, tolerances. A set of representative numerical examples is reported to validate the proposed IA-LBE method as well as to assess its effectiveness and reliability when dealing with realistic EM systems (e.g., antennas) for which the TF is not explicitly known.

eess.SY↗

arXiv2025

Inverse Source Method for Constrained Phased Array Synthesis through Null-Space Exploitation

A versatile approach for the synthesis of phased array (PA) antennas able to fit user-defined power pattern masks, while fulfilling additional geometrical and/or electrical constraints on the geometry of the array aperture and/or on the array excitations is presented. Such a synthesis method is based on the inverse source (IS) formulation and exploits the null-space of the radiation operator that causes the non-uniqueness of the IS problem at hand. More in detail, the unknown element excitations of the PA are expressed as the linear combination of a minimum-norm or radiating (RA) term and a suitable non-radiating (NR) component. The former, computed via the truncated singular value decomposition (SVD) of the array radiation operator, is devoted to generate a far-field power pattern that fulfills user-defined pattern masks. The other one belongs to the null-space of the radiation operator and allows one to fit additional geometrical and/or electrical constraints on the geometry of the array aperture and/or on the beam-forming network (BFN) when determined with a customized global optimization strategy. A set of numerical examples, concerned with various array arrangements and additional design targets, is reported to prove the effectiveness of the proposed approach.

eess.SY↗

arXiv2025

A Planning Strategy for Building a Heterogeneous Smart EM Environment

This paper presents a planning strategy for the deployment of smart electromagnetic entities (SEEs) to enhance the wireless coverage and the Quality-of-Service (QoS) in large urban areas. The integration of different technological solutions such as integrated access-and-backhaul nodes (IABs), smart repeaters (SRs), and electromagnetic skins (EMSs) is here addressed to enable an effective and efficient implementation of the concept of Smart Electromagnetic Environment (SEME). By combining the features of such heterogeneous SEEs and optimizing their number, positions, orientations, and configuration, the electromagnetic (EM) coverage in a set of Regions-of-Interest (RoIs) of outdoor scenarios is recovered and/or enhanced subject to installation costs and energy consumption requirements. Numerical validations from real-world scenarios are reported to assess the effectiveness of the proposed planning scheme as well as to show the potentialities of an heterogeneous deployment of SEMEs.

eess.SY↗

arXiv2025

Multi-Functional Polarization-Based Coverage Control through Static Passive EMSs

An innovative multi-functional static-passive electromagnetic skin (SP-EMS) solution is proposed to simultaneously support, in reflection, two independent wave-manipulation functionalities with a single meta-atoms arrangement on the EMS aperture when illuminated by two EM sources operating at the same frequency, but working in different polarization states. Towards this end, a simple reference meta-atom is designed first to enable an accurate and independent control of each polarization component of the local reflection tensor. Successively, the macro-scale synthesis of multi-polarization (MP) SP-EMSs (MP-SP-EMSs) is carried out by solving a global optimization problem where a cost function, which mathematically codes separate requirements for each polarization, is minimized with a customized version of the system-by-design (SbD) technique. Representative results from a set of numerical and experimental tests are reported to assess the feasibility of a multi-function EMS based on polarization diversity as well as the effectiveness and the robustness of the proposed method for the synthesis of MP-SP-EMSs.

eess.SY↗

arXiv2025

A Divide-and-Conquer Tiling Method for the Design of Large Aperiodic Phased Arrays

Due to the growing request from modern wireless applications of cost-affordable and high-gain scanning antenna solutions, the design of large phased arrays (PAs) with radiating elements organized into modular clusters with sub-array-only amplitude and phase control is a key topic. In this paper, an innovative irregular tiling method is proposed where, according to a divide-and-conquer strategy, the antenna aperture is subdivided into sub-areas that are locally domino-tiled by jointly fulfilling the full-coverage condition on the remaining untiled part of the PA support. Selected representative results, including comparisons with competitive state-of-the-art synthesis methods, are reported to prove the effectiveness and the computational efficiency of the proposed tiling approach. Use-cases of current relevance for low Earth orbit (LEO) satellite communications are discussed, as well, to provide the antenna designers useful practical guidelines for handling large PAs.

eess.SY↗

arXiv2025

One-Time Programmable Passive Electromagnetic Skins

The implementation of simple, inexpensive, and mass-production-oriented solutions for smart electromagnetic environments (SEMEs) is dealt with by introducing the concept of "one-time programmable" electromagnetic skins (OTP-EMSs). The simultaneous achievement of modular fabrication, (one-time) configurable reflection properties, passive-static operation, and zero maintenance is yielded by integrating expendable components at the atomic level of EMSs. Towards this end, an OTP meta-atom structure is properly defined and optimized to build EMSs featuring the desired scenario-dependent EM wave manipulation functionalities. In order to illustrate the features as well as to point out the potentialities of OTP-EMSs, a representative set of analytical, numerical, and experimental results is reported by considering different apertures, illuminations, and EM wave manipulation requirements.

eess.SY↗

arXiv2025

Time-Modulated EM Skins for Integrated Sensing and Communications

An innovative solution, based on the exploitation of the harmonic beams generated by time-modulated electromagnetic skins (TM-EMSs), is proposed for the implementation of integrated sensing and communication (ISAC) functionalities in a Smart Electromagnetic Environment (SEME) scenario. More in detail, the field radiated by a user terminal, located at an unknown position, is assumed to illuminate a passive TM-EMS that, thanks to a suitable modulation of the local reflection coefficients at the meta-atom level of the EMS surface, simultaneously reflects towards a receiving base station (BS) a "sum" beam and a "difference" one at slightly different frequencies. By processing the received signals and exploiting monopulse radar tracking concepts, the BS both localizes the user terminal and, as a by-product, establishes a communication link with it by leveraging on the "sum" reflected beam. Towards this purpose, the arising harmonic beam control problem is reformulated as a global optimization one, which is successively solved by means of an evolutionary iterative approach to determine the desired TM-EMS modulation sequence. The results from selected numerical and experimental tests are reported to assess the effectiveness and the reliability of the proposed approach.

eess.SY↗

arXiv2024

Unconventional Array Design in the Autocorrelation Domain -- Isophoric 1D Thinning

The synthesis of thinned isophoric arrays (TIAs) radiating mask-constrained patterns is addressed. By leveraging on the recently-introduced formulation of the design of antenna arrays in the autocorrelation-domain (AD), the TIA synthesis is recast as the matching of a target autocorrelation function derived from the user-defined guidelines and objectives. By exploiting the autocorrelation invariance of cyclic binary sequences, the AD solution space is significantly reduced and it is efficiently sampled by means of a discrete hybrid optimization approach. Two possible implementations of the AD-based TIA formulation are discussed and assessed in a set of representative numerical examples concerned with both ideal and real radiators, which are full-wave modeled to account for the mutual coupling effects. Comparisons with traditional pattern-domain (PD) synthesis methods are also considered to point out the features and the advantages of AD-based approaches.

eess.SP↗

arXiv2024

Synthesis of Wide-Angle Scanning Arrays through Array Power Control

A new methodology for the synthesis of wide-angle scanning arrays is proposed. It is based on the formulation of the array design problem as a multi-objective one where, for each scan angle, both the radiated power density in the scan direction and the total reflected power are accounted for. A set of numerical results from full-wave simulated examples - dealing with different radiators, arrangements, frequencies, and number of elements - is reported to show the features of the proposed approach as well as to assess its potentialities.

eess.SY↗

arXiv2024

On the Improvement of the Performance of Inexpensive Electromagnetic Skins by means of an Inverse Source Design Approach

A new methodology for the improvement of the performance of inexpensive static passive electromagnetic skins (SP-EMSs) is presented. The proposed approach leverages on the non-uniqueness of the inverse source problem associated to the SP-EMS design by decomposing the induced surface current into pre-image (PI) and null-space (NS) components. Successively, the unknown EMS layout and NS expansion coefficients are determined by means of an alternate minimization of a suitable cost function. This latter quantifies the mismatch between the ideal surface current, which radiates the user-defined target field, and that actually induced on the EMS layout. Results from a representative set of numerical experiments, concerned with the design of EMSs reflecting pencil-beam as well as contoured target patterns, are reported to assess the feasibility and the effectiveness of the proposed method in improving the performance of inexpensive EMS realizations. The measurements on an EMS prototype, featuring a conductive ink pattern printed on a standard paper substrate, are also shown to prove the reliability of the synthesis process.

eess.SY↗

arXiv2024

Co-Design of Low-Profile Linear Microstrip Arrays with Wide-Band Spatial Filtering Capabilities

The design of low-profile linear microstrip arrays with wide-band spatial filtering capabilities is dealt with. An innovative architecture, leveraging the angular selectivity of offset stacked patch (OSP) radiators, is proposed to implement phased arrays (PAs) with inter-element spacing larger than half-wavelength that feature remarkable grating lobes (GLs) suppression properties and an enhanced gain within a non-negligible down-looking scanning angular range. The PA layout is then obtained by optimizing the optimal micro-scale geometrical descriptors of the radiating elements so that the macro-scale electromagnetic (EM) features of the arising finite-size PA fulfill the user-defined requirements. A set of numerical test cases, concerned with a variation of the array size and its polarization, is presented to assess the capabilities, the flexibility, and the potentialities of the proposed spatial filtering technique (SFT) also in comparison with competitive state-of-the-art alternatives. The performance of a printed circuit board (PCB)-manufactured prototype are experimentally assessed, as well.

eess.SP↗

arXiv2024

Spline-Shaped Microstrip Edge-Fed Antenna for 77 GHz Automotive Radar Systems

An innovative millimeter-wave (mm-wave) microstrip edge-fed antenna (EFA) for 77 GHz automotive radars is proposed. The radiator contour is modeled with a sinusoidal spline-shaped (SS) profile characterized by a reduced number of geometrical descriptors, but still able to guarantee a high flexibility in the modeling for fulfilling challenging user-defined requirements. The SS-EFA descriptors are effectively and efficiently optimized with a customized implementation of the System-by-Design (SbD) paradigm. The synthesized EFA layout, integrated within a linear arrangement of identical replicas to account for the integration into the real radar system, exhibits suitable impedance matching, isolation, polarization purity, and stability of the beam shaping/pointing within the target band [76:78][GHz]. The experimental assessment, carried out with a Compact Antenna Test Range (CATR) system on a printed circuit board (PCB)-manufactured prototype, assess the reliability of the outcomes from the full-wave (FW) simulations as well as the suitability of the synthesized SS-EFA for automotive radars.

eess.SP↗

arXiv2024

Optically-Transparent EM Skins for Outdoor-to-Indoor mm-Wave Wireless Communications

Optically-transparent opportunistic electromagnetic skins (OTO-EMSs) are proposed to enable outdoor-to-indoor (O2I) millimiter-wave (mmW) wireless communications with existing windows/glass-panels. More in detail, static passive EMSs consisting of optically-transparent conducting patterned layers attached to standard glass-panels are designed. Towards this end, both the phase coverage and the optical transparency of a meshed copper-based meta-atom printed on a non-dedicated insulated glass substrate are optimized. Successively, the feasibility of OTO-EMSs able to support mmW high-efficiency O2I transmissions along non-Snell refraction directions is numerically demonstrated.

eess.SP↗

arXiv2024

An Opportunistic Source Synthesis Method for Smart Electromagnetic Environments

In the framework of the "Smart ElectroMagnetic Environment" (SEME), an innovative strategy leveraging Equivalence Source concepts is introduced for enhancing the performance of large-scale outdoor wireless communication systems. The proposed Opportunistic Sources Synthesis (OSS) approach is aimed at unconventionally synthesizing the primary source (i.e., the base transceiver station (BTS) antenna array), so that the complex scattering phenomena induced in the surrounding scatterers are profitably exploited to enhance the received power within user-defined regions of interest (RoIs). To yield a computationally feasible synthesis process, an innovative "Embedded-plus-Environment Patterns" (EPEPs) method is introduced. A set of representative numerical examples, concerned with realistic large-scale outdoor scenarios, is presented to assess the effectiveness and the efficiency of the proposed optimization-driven approach for a realistic SEME implementation.

eess.SY↗

arXiv2024

Improving the Imaging Performance of Microwave Imaging Systems by Exploiting Virtual Antennas

Starting from the observation that the correlation coefficient defined by the scattered field data tested by two adjacent antennas decreases with the noise, it turns out that the imaging performance can be improved by adding non-redundant scattered field information through more measuring antennas.However, adding more measuring antennas faces practical challenges such as the limited antenna space, high experimental expenses, and a prolonged data collection time. Therefore, the frequency-domain zero-padding (FDZP) interpolation method is proposed to acquire scattered field data on more virtual antennas. To process the data, a linear inversion algorithm based on the modified Born approximation (MBA) and the nonlinear subspace-based optimization method (SOM) are used to image scatterers of moderate and high contrasts, respectively. The effectiveness and the reliability of the proposed approach are then assessed against synthetic data, semi-experimental data from a full-wave simulation software, and experimental data.

physics.app-ph↗

arXiv2024

A Physics-Driven AI Approach for Microwave Imaging of Breast Tumors

In this paper, an innovative microwave imaging (MI) approach for breast tumor diagnosis is proposed that employs a differential formulation of the inverse scattering problem (ISP) at hand to exploit arbitrary-fidelity priors on the inhomogeneous reference/healthy tissues. The quantitative imaging of the unknown tumor is then rephrased into a global optimization problem, which is efficiently solved with an ad-hoc physics-driven artificial intelligence (AI) strategy inspired by the concepts and guidelines of the System-by-Design (SbD) paradigm. The effectiveness, the robustness, the reliability, and the efficiency of the proposed method are assessed against both synthetic and experimental data.

eess.SP↗

arXiv2023

Memory-Enhanced Dynamic Evolutionary Control of Reconfigurable Intelligent Surfaces

An innovative evolutionary method for the dynamic control of reconfigurable intelligent surfaces (RISs) is proposed. It leverages, on the one hand, on the exploration capabilities of evolutionary strategies and their effectiveness in dealing with large-scale discrete optimization problems and, on the other hand, on the implementation of memory-enhanced search mechanisms to exploit the time/space correlation of communication environments. Without modifying the base station (BS) beamforming strategy and using an accurate description of the meta-atom response to faithfully account for the micro-scale EM interactions, the RIS control (RISC) algorithm maximizes the worst-case throughput across all users without requiring that the Green's partial matrices, from the BS to the RIS and from the RIS to the users, be (separately) known/measured. Representative numerical examples are reported to illustrate the features and to assess the potentialities of the proposed approach for the RISC.

eess.SY↗

arXiv2023

Design of Clustered Phased Arrays by Means of an Innovative Power Pattern Matching-Driven Method -- The Linear Array Case

The design of sub-arrayed phased arrays (PAs) with sub-array-only amplitude and phase controls that afford arbitrary-shaped power patterns matching reference ones is addressed. Such a synthesis problem is formulated in the power pattern domain and an innovative complex-excitations clustering method, which is based on the decomposition of the reference power pattern in a number of elementary patterns equal to the array elements, is presented. A set of representative results is reported to illustrate the features of the proposed approach as well as to assess its effectiveness in comparison with benchmark results from the state-of-the-art (SoA) excitation matching-based clustering methods.

cs.IT↗