Abstract
The rapid progress in radar and communication places increasing demands on low-latency and energy-efficiency array signal processing methods. There is an emerging direction of constructing analog computing processors for directly processing electromagnetic (EM) waves. However, the existing methods are constrained by 2D physical aperture and imprecise design process with inefficient computing architecture, resulting in limited sensing resolution and number of separated sources. Here, we present a fully-analog array signal processor (FASP) using 3D aperture engineering framework to perform super-resolution direction-of-arrival estimation, source number estimation, and multi-channel source separation in parallel for both coherent and incoherent sources. 3D aperture engineering is realized by constructing deep cascaded metasurface layers so that the diffractive propagation from oblique incident fields can be layer-wise modulated and piecewise encoded for perceiving EM fields far exceeding physical aperture limits. The multi-dimensional synthetic aperture (MSA) training is developed to characterize the metasurface modulation and optimize the neuro-augmented physical model for extending system aperture and generating high-order nonlinear angular response. FASP orthogonalizes the array response vectors of communication channels to map them into antenna detectors in the analog domain. The $N$-layer FASP has the capability to achieve ~N times higher angular resolution than the Rayleigh diffraction limit. Experiments further validate the source number estimation and independent channel separation of 10-target that can suppress radar jamming signals by ~20 dB and enhance channel communication capacity by 13.5 times at 36~41 GHz. FASP heralds a paradigm shift in signal processing for super-resolution optics, advanced radar, and 6G communications.
Abstract (translated)
雷达和通信技术的快速进步对低延迟和能源效率高的阵列信号处理方法提出了越来越高的要求。一种新兴的方向是构建用于直接处理电磁（EM）波的模拟计算处理器。然而，现有的方法受到二维物理孔径限制以及设计过程不精确且计算架构效率低下的制约，导致感知分辨率有限及分离源的数量受限。在这里，我们提出了一种使用三维孔径工程技术进行全模拟阵列信号处理器（FASP），能够同时并行执行超分辨到达方向估计、源数量估计和多通道源分离，适用于相干和非相干源。 通过构建深层级联的元表面层来实现三维孔径工程，这样可以逐层调节来自斜入射场的衍射传播，并分段编码感知超过物理孔径限制的电磁场。开发了多维合成孔径（MSA）训练技术以表征元表面调制并优化神经增强的物理模型，以便扩展系统孔径并生成高阶非线性角度响应。 FASP通过正交化通信通道的阵列响应向量，并将其映射到模拟域中的天线检测器来工作。具有$N$层的FASP能够实现约$N$倍于瑞利衍射极限的角度分辨率。 实验进一步验证了10个目标源的数量估计和独立通道分离，可以抑制雷达干扰信号大约20分贝，并在36~41 GHz频段上将信道通信容量提高13.5倍。FASP预示着超分辨光学、先进雷达及第六代（6G）通信领域中的信号处理范式转变的到来。
URL
https://arxiv.org/abs/2603.00995
