🤖 AI Summary
Existing reconfigurable electromagnetic structures (REMS)—including reconfigurable intelligent surfaces (RIS) and reconfigurable reflectarrays (RRAs)—suffer from a fundamental trade-off between computational efficiency and physical fidelity in modeling, forcing control algorithms to rely on oversimplified, inaccurate surrogate models. This work proposes a unified, physics-informed modeling framework that integrates circuit-theoretic descriptions with far-field electromagnetic interaction characterization. Leveraging only a single full-wave simulation, the framework enables rapid prediction of the complete far-field radiation response for arbitrary tunable element configurations. It rigorously satisfies Maxwell’s equations and consistently incorporates mutual coupling, polarization effects, dielectric/conductor losses, nonreciprocal responses, and thermal noise. The resulting model achieves accuracy comparable to full-wave simulation while accelerating computation by over two orders of magnitude. Furthermore, it enables the first real-time, high-fidelity multi-user beam and null synthesis algorithm capable of joint beamforming and null-steering optimization.
📝 Abstract
Reconfigurable electromagnetic structures (REMSs), such as reconfigurable reflectarrays (RRAs) or reconfigurable intelligent surfaces (RISs), hold significant potential to improve the spectral efficiency of wireless communication systems and the accuracy of wireless sensing systems. Even though several REMS modeling approaches have been proposed in recent years, the literature lacks models that are both computationally efficient and physically consistent. As a result, algorithms that control the reconfigurable elements of REMSs (e.g., the phase shifts of a RIS) are often built on simplistic and thus inaccurate models. To enable physically accurate REMS-parameter tuning, we present a new framework for efficient and physically consistent modeling of general REMSs. Our modeling method combines a circuit-theoretic approach with a new formalism that describes a REMS’s interaction with the electromagnetic (EM) waves in its far-field region. Our modeling method enables efficient computation of the entire far-field radiation pattern for arbitrary configurations of the REMS reconfigurable elements once a single full-wave EM simulation of the non-reconfigurable parts of the REMS has been performed. The predictions made by our framework align with the physical laws of classical electrodynamics and model effects caused by inter-antenna coupling, non-reciprocal materials, polarization, ohmic losses, matching losses, influence of metallic housings, noise from low-noise amplifiers, and noise arising in or received by antennas. In order to validate the efficiency and accuracy of our modeling approach, we (i) compare our modeling method to EM simulations and (ii) conduct a case study involving an RRA that enables simultaneous multiuser beam- and null-forming using a new, computationally efficient, and physically accurate parameter tuning algorithm.