Design and Channel Modeling of Electromagnetically Reconfigurable Antennas

TL;DR

The paper addresses the limitation of static antenna arrays by introducing electromagnetically reconfigurable antennas (ERAs) built on fluid antenna system (FAS) concepts, adding electromagnetic degrees of freedom at the element level. It develops an EM-domain MIMO channel framework, deriving ${\bf H}_{\mathrm{ER}} = \gamma{\bf D}{\bf H}_{\mathrm{EM}}{\bf B}^{\mathsf{T}}$ where ${\bf H}_{\mathrm{EM}}$ encodes LoS and multipath via tensor products with radiation-pattern dictionaries, linking per-element pattern reconfiguration to channel shaping. A practical ERA element with liquid-metal directors/reflector is designed, forming a 12-element ULA, and beampattern synthesis is defined to compare with conventional arrays. Full-wave HFSS validation demonstrates a beam gain of $${13.5}$$ dBi at $135^{\circ}$, a $2.5$ dB improvement over a fixed-pattern antenna, and a $5.5$ dB reduction in a major side-lobe, corroborating the proposed model. The work validates a practical ERA-enabled MIMO framework with tunable channel characteristics, suggesting pathways for broader reconfigurability (frequency/polarization) and integration with RIS/ISAC in future wireless networks.

Abstract

In this work, a novel design of electromagnetically reconfigurable antennas (ERAs) based on a fluid antenna system (FAS) is proposed, and the corresponding wireless channel model is established. Different from conventional antenna arrays with static elements, the electromagnetic characteristics of each array element in the proposed ERA can be flexibly reconfigured into various states, introducing electromagnetic degrees of freedom to enhance wireless system performance. Based on the proposed ERA design, the corresponding channel model is developed. Finally, full-wave simulations are conducted to validate the overall design concept. The results reveal that a gain enhancement of 2.5 dB is achieved at a beamforming direction.

Figures (6)

• Figure 1: The ERA array element design.
• Figure 2: The operation principle of the ERA array element.
• Figure 3: The full-wave simulated radiation patterns of the EAR element at different reconfigurable states.
• Figure 4: Array configuration of the EAR.
• Figure 5: Simplified hardware block diagram of a single-user MIMO system based on ERAs and RF phase shifters.