Flexible coupler antenna (FCA) is a new technique that aims to improve the performance of wireless communication networks by smartly translating low-cost passive couplers around fixed-position active antennas to reshape the induced currents on the passive elements for radiation. Specifically, different couplers can independently control their positions/rotations at the transceiver and thereby collaboratively achieve mechanical beamforming for directional signal enhancement or nulling. The position and/or rotation reconfiguration of passive couplers provides a new and cost-effective means of enhancing wireless communication performance, while significantly reducing the antenna and radio-frequency (RF) chain costs of conventional active arrays. The compact and low form-factor structure of the FCA makes it particularly appealing for devices with stringent size, weight, and power (SWAP) constraints. In this article, we provide an overview of FCA to reveal its promising capabilities in wireless networks, including its system modeling, practical implementation, and competitive advantages over existing techniques. We present a variety of FCA-enabled performance enhancements in terms of mechanical beamforming gain, path-loss reduction, fading mitigation, spatial multiplexing gain, interference suppression, and geometric gain. Furthermore, we elaborate on the design challenges of FCA as well as promising solutions, and discuss the key applications of FCA in wireless networks. Finally, numerical results are presented to verify the substantial capacity gains enabled by FCA-aided transmission in wireless networks.

翻译：柔性耦合器天线（FCA）是一种新技术，旨在通过智能地在固定位置有源天线周围布置低成本的被动耦合器，重塑被动单元上的感应电流以实现辐射，从而提升无线通信网络的性能。具体而言，不同的耦合器可在收发端独立控制其位置/旋转，进而协同实现机械波束赋形，用于定向信号增强或零陷生成。被动耦合器的位置和/或旋转重构提供了一种新颖且经济高效的手段来提升无线通信性能，同时显著降低了传统有源阵列的天线和射频（RF）链成本。FCA紧凑且低轮廓的结构特性使其特别适用于受尺寸、重量和功耗（SWAP）严格约束的设备。本文概述了FCA，揭示了其在无线网络中的潜力能力，包括系统建模、实际实现以及相对于现有技术的竞争优势。我们从机械波束赋形增益、路径损耗降低、衰落缓解、空间复用增益、干扰抑制和几何增益等方面，展示了FCA带来的多种性能提升。此外，我们详细阐述了FCA的设计挑战及有前景的解决方案，并讨论了FCA在无线网络中的关键应用。最后，通过数值结果验证了FCA辅助传输在无线网络中带来的显著容量增益。