AI 中文总结
该研究开发了一款28 GHz变容二极管RIS平台，建立了器件到系统的验证框架，实现±45°内精确波束转向，还支持多波束合成，为毫米波RIS研发提供了严谨基础。
AI 中文摘要
本文提出了一种具备连续相位控制的基于变容二极管的28 GHz可重构智能表面（RIS）平台，并建立了用于可编程波前控制与合成的统一器件到系统验证框架。所提出的RIS包含96个独立控制的单元，每个单元采用单个变容二极管，配备板载集成的模拟偏置控制架构。该平台基于经实验验证的单元模型，在正入射下提供约300°的连续反射相位调谐。其分析框架结合了测得的喇叭天线照射、有限相位可用性及单元反射损耗，将器件级特性与波束成形性能相关联。通过近场到近场表征、近场到远场波束转向及远场到远场无线链路实验对其进行评估。近场到远场结果显示分析预测、全波仿真与测量结果吻合良好，而远场到远场响应与仿真及一阶链路预算估计一致。在三个方位平面内的±45°范围内，所有被测角度均实现了精确转向，最大偏差约为2°。包含驱动器和偏置网络的完整原型仅消耗0.85 W功率，估计全口径重构时间约为50 ms。除波束转向外，同一平台还可利用通用射频口径与控制架构，对3位、2位和1位相位量化及可编程多波束波前合成进行实验研究。总体而言，这些结果弥合了实际变容二极管特性、分析建模与可编程波前合成之间的差距，为开发和实验验证连续可调的毫米波RIS提供了严谨基础。
英文摘要
This paper presents a 28 GHz varactor-based reconfigurable intelligent surface (RIS) platform with continuous phase control and establishes a unified device-to-system validation framework for programmable wavefront control and synthesis. The proposed RIS comprises 96 independently controlled elements, each employing a single varactor diode, with a board-integrated analog-bias control architecture. It builds on an experimentally validated unit-cell model providing approximately 300° of continuous reflection-phase tuning at normal incidence. An analytical framework incorporating measured horn illumination, finite phase availability, and unit-cell reflection losses consistently relates device-level characteristics to beamforming performance. It is evaluated via near-field-to-near-field characterization, near-field-to-far-field beam-steering, and far-field-to-far-field wireless-link experiments. The near-field-to-far-field results show close agreement among analytical predictions, full-wave simulations, and measurements, while the far-field-to-far-field response agrees with simulation and a first-order link-budget estimate. Accurate steering is demonstrated for all investigated angles within $\pm$45° across three azimuthal planes, with maximum deviation of approximately 2°. The complete prototype, including driver and bias network, draws only 0.85 W with an estimated full-aperture reconfiguration time of approximately 50 ms. Beyond beam steering, the same platform enables experimental investigation of 3-bit, 2-bit, and 1-bit phase quantization and programmable multi-beam wavefront synthesis using a common RF aperture and control architecture. Collectively, these results bridge realistic varactor behavior, analytical modeling, and programmable wavefront synthesis, providing a rigorous basis for developing and experimentally validating continuously tunable millimeter-wave RISs.
