Evolution of Multi-Port Transceiver Systems: From Foundational Architectures to Virtualized and Reconfigurable Platforms

The landscape of radio-frequency (RF) front-end design has evolved significantly over the past decades, driven by the demand for higher integration, reduced complexity, and enhanced reconfigurability. Among the key innovations, the six-port technique has emerged as a foundational architecture enabling passive and highly linear RF signal processing. Building upon its principles, multi-port front-ends have expanded to support complex modulation schemes, multi-functional operations, and millimeter-wave (mmW) integration. With the progression of integrated circuit technologies and software-defined platforms, these architectures now serve as the backbone for multifunctional communication and sensing systems. Recent developments have introduced novel frameworks such as the virtual receiver matrix (VRM) and virtual transceiver matrix (VTM), which provide dynamic analog reconfiguration for adaptive operation. In parallel, reconfigurable intelligent surfaces (RISs) have also gained attention for their ability to manipulate electromagnetic waves passively, offering new avenues for wireless front-end design. This review presents a comprehensive analysis of the historical foundations, technological advancements, and emerging trends in multi-port RF front-ends, highlighting the trajectory from classical six-port receivers to futuristic VRM, VTM, and RIS-based architectures.