We propose a novel receiver architecture that preserves the performance benefits of multiport selection in fluid-antenna systems while requiring only a very small number of radio-frequency (RF) chains. The resulting fluid-antenna hybrid multiport (FAHM) receiver effectively decouples port selection from signal combining by integrating a low-complexity analog combining network similar to those used in conventional hybrid multiantenna designs. We develop a stopping criterion to determine the number of selected ports, which limits the performance loss associated with port selection, and then design the hybrid combiner for a given RF-chain budget. The FAHM architecture is evaluated in a multiuser set-up operating under slow fluid-antenna multiple access (FAMA). In this scenario, a FAHM implementation with only 2 RF chains showcases a performance comparable to a fully-digital conventional multiport scheme with a much larger number of RF chains. Additionally, the proposed receiver architecture attains over 60% reduction in computational burden when integrated with a novel efficient implementation of the state-of-the-art generalized-eigenvector port-selection method.

翻译：我们提出了一种新型接收机架构，该架构在保持流体天线系统中多端口选择性能优势的同时，仅需极少数量的射频链路。所提出的流体天线混合多端口（FAHM）接收机通过集成类似于传统混合多天线设计中的低复杂度模拟合并网络，有效解耦端口选择与信号合并。我们开发了一种停止准则来确定所选端口数量，以限制与端口选择相关的性能损失，然后针对给定的射频链路预算设计混合合并器。该FAHM架构在慢速流体天线多址接入（FAMA）多用户场景下进行了评估。在此场景中，仅配备2个射频链路的FAHM实现展现了与具有更多射频链路的全数字传统多端口方案相当的性能。此外，当与更先进的特征向量端口选择方法的高效实现集成时，所提出的接收机架构在计算负担上实现了超过60%的降低。