Millimeter-wave and Terahertz Real-Time and Space Processing based on Metamaterial Technology

如今，通信、仪器仪表、雷达、成像和传感器等领域对更快、更可靠和无处不在的无线电系统的需求呈爆炸式增长，这对微波(MW)、毫米波(MmW)和太赫兹(THz)工程提出了前所未有的挑战。最近，主流趋势是越来越重视数字信号处理(DSP)。然而，在提供器件紧凑性和处理灵活性的同时，数字信号处理器也存在着固有的缺陷，如速度有限、模数转换成本高、功耗高、高频性能差等，导致严重的技术瓶颈。例如，在无线通信方面，预计未来5年数据容量需求将增长1,000倍，业界专家普遍认为，目前的技术在很大程度上不足以满足这些需求！因此，迫切需要新的范式和颠覆性的技术解决方案。*拟议的研究计划提出了一种截然不同的方法，通过利用超材料技术来应对上述挑战。受超快光学的启发，它将开发毫米波和太赫兹实时模拟信号处理，包括以原始模拟形式处理高频信号，并实时实现特定处理操作，作为基于DSP的处理的替代方案。这本质上是时间色散工程，其中将详细描述线性组件，例如基于超材料的“相控器”(借用自声学)和非线性组件“压缩器”(压缩器和扩展器的合成词)，以前所未有的方式控制MWW/THz系统的相位和群延迟。*由于电磁波在时间和空间中传播，空间色散工程似乎是对其时间对应的自然处理的补充。因此，拟议的计划将开发新型的毫米波和太赫兹天线和表面(在单色制度下运行的超表面)，这一次的灵感来自于光学模拟信号处理，例如涡旋波天线和广义折射表面。最后，该计划将研究同时作为时间和空间处理器运行的设备，即“Phasennas”、“Compandenas”和“Surfphasennas”。*拟议的时间/空间/时空处理器将导致非常多样化的应用，如实时/空间傅里叶变换和频谱分析、实时卷积/相关器、非互易设备、色散编码器、涡旋多路复用器、麦克斯韦空间系统和时空斗篷，应用领域广泛，如通信、无线能量传输、传感/成像、仪器、安全/防御、生物医学、纳米电磁学和天文学。**

Today's exploding demand for faster, more reliable, and ubiquitous radio systems in communications, instrumentation, radar, imaging and sensors poses unprecedented challenges in microwave (mw), millimeter-wave (mmw) and terahertz (THz) engineering. Recently, the predominant trend has been to place increasing emphasis on digital signal processing (DSP). However, while offering device compactness and processing flexibility, DSP suffers from intrinsic drawbacks, such as limited speed, high-cost analog-digital conversion, high power consumption, and poor performance at high frequencies, leading to serious technological bottlenecks. For instance, in wireless communications, a 1,000-fold increase in data capacity demand over the 5 next years has been predicted, and it is widely recognized by industrial experts that current technologies will be largely insufficient to meet such requirements! Therefore, novel paradigms and disruptive technological solutions are urgently needed.***The proposed research program proposes a radically different approach to address the aforementioned challenges by leveraging metamaterial technology. Inspired from ultrafast optics, it will develop mmw and THz real-time analog signal processing, consisting in manipulating high-frequency signals in their pristine analog form and in real time to realize specific processing operations, as an alternative to DSP-based processing. This is essentially temporal dispersion engineering, where linear components such as metamaterial-based "phasers" (term borrowed from acoustics) and nonlinear components called "companders" (portmanteau for compressors and expandors) will be elaborated to control the phase and group delay of mww/THz systems in unprecedented fashions. ***As electromagnetic waves propagate both in time and space, spatial dispersion engineering appears to be a natural processing complement to its temporal counterpart. The proposed program will thus develop, this time inspired from optical analog signal processing, novel types of mmw and THz antennas and surfennas (metasurfaces operated in the monochromatic regime), such as for instance vortex wave antennas and generalized refraction surfennas. Finally, the program will investigate devices operating simultaneously as temporal and spatial processors, namely "phasennas," "compandenas" and "surfphasennas."***The proposed time/space/spacetime processors will lead to a great diversity of applications, such as real-time/space Fourier transformers and spectrogram analyzers, real-time convolvers/correlators, nonreciprocal devices, dispersion encoders, vortex multiplexers, maxwellian spatial systems, and space-time cloaks, with application areas as various as communications, wireless energy transfer, sensing/imaging, instrumentation, security/defense, biomedicine, nanoelectromagnetics and astronomy.**