Mutual Coupling in Dynamic Metasurface Antennas: Foe, but also Friend

TL;DR

This paper reveals that mutual coupling in dynamic metasurface antennas, often seen as a complication, can actually enhance control over radiation patterns, leading to improved beamforming and sensing capabilities.

Contribution

It demonstrates that mutual coupling can be harnessed to improve DMA radiation pattern control using a physics-based model, challenging previous neglect of this effect.

Findings

Mutual coupling increases radiation pattern sensitivity to DMA configurations.

Enhanced sensitivity leads to higher fidelity in pattern synthesis.

Design strategies should incorporate mutual coupling benefits.

Abstract

Dynamic metasurface antennas (DMAs), surfaces patterned with reconfigurable metamaterial elements (meta-atoms) that couple waves from waveguides or cavities to free space, are a promising technology to realize 6G wireless base stations and access points with low cost and power consumption. Mutual coupling between the DMA's meta-atoms results in a non-linear dependence of the radiation pattern on the DMA configuration, significantly complicating modeling and optimization. Therefore, mutual coupling has to date been considered a vexing nuance that is frequently neglected in theoretical studies and deliberately mitigated in experimental prototypes. Here, we demonstrate the overlooked property of mutual coupling to boost the control over the DMA's radiation pattern. Based on a physics-compliant DMA model, we demonstrate that the radiation pattern's sensitivity to the DMA configuration significantly depends on the mutual coupling strength. We further evidence how the enhanced sensitivity under strong mutual coupling translates into a higher fidelity in radiation pattern synthesis, benefiting applications ranging from dynamic beamforming to end-to-end optimized sensing and imaging. Our insights suggest that DMA design should be fundamentally rethought to embrace the benefits of mutual coupling. We also discuss ensuing future research directions related to the frugal characterization of DMAs based on compact physics-compliant models.