We present a method for the mitigation of quantization lobes in single-bit reconfigurable reflective surfaces (RRSs). Typically, RRSs are planar beamforming structures consisting of hundreds or thousands of antennas with integrated tunable switches. Under plane-wave illumination, single-bit RRSs suffer from undesired side lobes or quantization lobes, which are caused by the periodicity of the errors due to the limited number of bits used in phase quantization. In this article, we present a topology that suppresses the quantization lobes using single-layer, 1-bit RRSs, by implementing a fixed but random phase delay in every unit-cell. The introduction of phase randomization breaks the periodicity of the quantization errors, thus reducing the quantization lobe level (QLL). We carry out a theoretical analysis to demonstrate the effect of phase randomization in RRSs, and for the first time, provide the condition for choosing the range of randomization required to achieve the lowest sidelobe level (SLL). Leveraging this condition, we design a single-layer, 1-bit $30\times 30$ randomized RRS at 222.5 GHz. The reflective surface is fabricated on a thin, low-loss alumina ribbon ceramic wafer from Corning Inc. using a simplified fabrication technique suitable for large-scale production of mmWave/THz RRSs. Finally, we present the radar cross-section (RCS) characterization results obtained from a quasi-optical measurement setup validating the mitigation of quantization lobes using the proposed randomization technique.

中文翻译：

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减少毫米波低位可重构反射面中的量化瓣

我们提出了一种减轻单位可重构反射面（RRS）中量化瓣的方法。通常，RRS是平面波束成形结构，由数百个或数千个带有集成可调开关的天线组成。在平面波照射下，单个比特的RRS遭受不希望的旁瓣或量化瓣，这是由于相位量化中使用的位数有限而导致的错误周期性所致。在本文中，我们提出了一种拓扑结构，该拓扑结构通过在每个单位单元中实现固定但随机的相位延迟来使用单层1位RRS抑制量化瓣。相位随机化的引入打破了量化误差的周期性，从而降低了量化波瓣水平（QLL）。我们进行理论分析以证明RRS中相位随机化的效果，并且首次为选择实现最低旁瓣电平（SLL）所需的随机化范围提供了条件。利用这种情况，我们设计了一个单层1位 30美元/次30美元 222.5 GHz的随机RRS。使用适用于大规模生产mmWave / THz RRS的简化制造技术，在康宁公司的薄，低损耗氧化铝带状陶瓷晶片上制造反射表面。最后，我们介绍了从准光学测量设置获得的雷达横截面（RCS）表征结果，该设置使用所提出的随机技术验证了量化瓣的缓解。