Abstract
Project Description The DAESY project (Digital Twin for Active Electronically Scanned Arrays) addresses the growing complexity affecting the design of Active Electronically Scanned Arrays (AESAs), which play a critical role in next generation 5G/6G telecommunications, radar systems, sensing, and wireless power transfer. These arrays electronically steer electromagnetic beams through precise phase control across multiple antenna elements. However, as frequencies reach the millimeter-wave range, designers face increasing challenges due to element integration, strong mutual coupling, nonlinear amplifier behavior, and the high cost and time demands of repeated prototyping as well as over-the-air (OTA) testing. To overcome these issues, DAESY introduces a digital twin, namely, a highly detailed virtual model of a beamforming array that seamlessly integrates hardware-in-the-loop (HIL) active load-pull measurements, full-wave electromagnetic (EM) simulation, and nonlinear device modeling. The project is structured across seven interconnected work packages (A1 to A7), managed by three academic institutions. The University of Bologna (UBO) leads system-level modeling, load-pull measurements, and final OTA validation. The University of Rome “Tor Vergata” (UTV) contributes with radio frequency (RF) power amplifier (PA) design, while the University of Perugia (UPG) is responsible for antenna array layout and EM simulation. Together, these institutions form a cohesive consortium focused on developing a unified design and validation framework. Activity A1 will emulate the dynamic interactions between antenna elements and PAs using active load-pull methods. Activity A2 combines EM and nonlinear circuit simulations to produce a precise system-level model. Activities A3 and A4 focus on the design of load-insensitive amplifier architectures and the optimization of antenna elements, respectively. During Activity A5, these components will be integrated into a comprehensive modeling framework to support beamforming trade-off analysis and topology selection. Hardware prototypes in 1×4 and 2×2 configurations, operating at 28 GHz, will be fabricated in Activity A6 using hybrid monolithic microwave integrated circuit (MMIC) and printed circuit board (PCB) technologies. Finally, Activity A7 will deliver a full OTA validation campaign using an automated test bench. The project timeline is defined by three key milestones: M1 (digital twin deployment), M2 (beamformer topology finalization and prototyping), and M3 (complete experimental validation via OTA measurements). Objectives The primary objective of DAESY is to establish a scalable and accurate digital twin ecosystem for AESA design, leveraging advanced electronic design automation (EDA) tools. Four technical goals drive this mission. First, the project will comprehensively assess how array integration and scaling affect electromagnetic behavior, with a focus on mutual coupling effects and their impact on radiation patterns and amplifier loading. Second, it will analyze and test load-insensitive PA topologies capable of maintaining consistent performance across varying impedance conditions caused by beam steering and inter-element coupling. Third, DAESY will implement hybrid simulation methodologies that combine full-wave EM analysis with behavioral models for nonlinear circuit simulation. This includes an advanced HIL active load-pull platform to realistically emulate antenna and PA interactions without requiring full-array hardware. Fourth, the project will establish fast, model-based procedures for array-level performance prediction and calibration. These will incorporate sensitivity analysis, surrogate modeling, and iterative optimization workflows under realistic 5G modulated signal conditions, enabling precise control over key metrics such as beam pointing accuracy, linearity including error vector magnitude (EVM) and adjacent channel power ratio (ACPR), and energy efficiency. In addition to these technical objectives, DAESY aims to shorten development cycles, reduce prototyping costs, and increase design flexibility. By supporting both academic research and industrial applications, the project will enable simulation-driven AESA deployment and foster cost-effective innovation in RF system design. Expected Results At the conclusion of the project, DAESY will deliver a validated digital twin capable of accurately capturing nonlinear interactions between amplifiers and antenna elements while supporting a variety of array topologies at practical scales. This tool will enable designers to simulate complete system behavior without building full hardware implementations. The development process will yield two physical prototypes, a 1×4 and a 2×2 beamforming array, operating at 28 GHz and built using hybrid MMIC and PCB technology. These will be evaluated using the integrated OTA platform. The OTA setup, developed at UBO under Activity A7, will support fully automated measurement of radiation patterns and performance metrics relevant to telecommunications, such as EVM and ACPR, under realistic wideband modulation. The digital twin's predictive capabilities will be assessed by comparing simulated and measured results. These outcomes will strengthen European digital sovereignty and competitiveness by enabling faster and more affordable prototyping, reducing environmental impact, and accelerating the industrial and academic deployment of advanced AESA technologies. Results The project addressed the development and experimental validation of methodologies for the analysis of active phased-array antennas operating in the Frequency Range 2 (FR2) of the Fifth Generation (5G) communication standard. The activities combined the implementation of a digital twin framework with the realization of a dedicated 27 GHz active phased-array prototype, conceived as an experimental platform for validating the proposed approach under realistic operating conditions. The activities relied on the complementary expertise of the three project partners. The University of Bologna established experimental infrastructures and developed the measurement techniques, nonlinear behavioral models, and the overall digital twin framework. The University of Rome “Tor Vergata” designed and realized custom high-power amplifier modules in Gallium Nitride (GaN) technology. The University of Perugia was responsible for the antenna architecture, passive beamforming networks, and related electromagnetic models. A key outcome of the project was the development of a measurement-based methodology capable of reproducing the operating conditions experienced by power amplifiers embedded in active phased-array antennas through the repeated characterization of a single device under test (DUT). This methodology was complemented by fast load-pull techniques for the efficient acquisition of nonlinear measurement data under controlled loading conditions and by the derivation of amplifier behavioral models suitable for system-level simulations under broadband communication signals. The resulting models and measurement techniques were combined within a digital twin environment integrating nonlinear device models, electromagnetic simulations, and mutual-coupling-aware array analysis. This framework supports the study, design, optimization, and linearization of active phased-array transmitters operating at millimeter-wave frequencies by enabling the prediction of system performance under realistic operating conditions, before realizing the actual array. The proposed approach was experimentally validated through the design, fabrication, and characterization of a dedicated 27 GHz active phased-array prototype comprising a passive Rotman-lens beamforming network, custom GaN high-power amplifier modules as the active elements, and two interchangeable radiating arrays based on microstrip patch and Substrate Integrated Waveguide (SIW) technologies. Conducted and over-the-air measurements showed good agreement with the corresponding simulations, supporting the adopted design approach and validating the integrated demonstrator. Experimental characterization of the complete prototype was carried out in an anechoic chamber using broadband signals representative of 5G FR2 communications. Measurements acquired under different beam-steering configurations and operating power levels were compared with the predictions generated by the digital twin, showing good overall agreement across the investigated operating conditions and providing experimental validation of the proposed modeling framework. The experimental campaign also highlighted practical aspects related to the calibration of highly integrated millimeter-wave hardware, particularly concerning the repeatability of high-frequency interconnections and in situ measurements. These findings identify directions for further refinement of both the hardware implementation and the associated measurement procedures. Overall, the project delivered an integrated framework combining nonlinear device characterization and modeling, mutual-coupling-aware emulation and electromagnetic simulation. The resulting digital twin, together with the dedicated 27 GHz active phased-array demonstrator and the associated measurement and modeling techniques, provides a foundation for the study, design, optimization, and linearization of next-generation active beamforming systems for future wireless communication applications.
Dettagli del progetto
Responsabile scientifico: Gian Piero Gibiino
Strutture Unibo coinvolte:
Dipartimento di Ingegneria dell'Energia Elettrica e dell'Informazione "Guglielmo Marconi"
Coordinatore:
ALMA MATER STUDIORUM - Università di Bologna(Italy)
Contributo totale di progetto: Euro (EUR) 244.493,00
Contributo totale Unibo: Euro (EUR) 103.928,00
Durata del progetto in mesi: 24
Data di inizio
30/11/2023
Data di fine:
28/02/2026
