A Novel Hardware Architecture to Time-Reverse Electromagnetic Signals with Low Cost

时间反演技术能够在空间和时间上聚焦波。它有可能实现广泛的革命性设备，如广泛的先前研究所示。特别是，“声信号时间反演”已成功地用于水下通信和声纳。然而，迄今为止，还没有报道用于“电磁信号的时间反演”的实用系统;主要的相关瓶颈是时间反演电磁信号所需的昂贵/庞大的硬件。本研究提出一种新的频率域架构，以低成本对电磁信号进行时间反演。 它有望从根本上解决与“电磁信号的时间反转”相关的“高成本难题”，进而实现电磁波时空聚焦的高效和鲁棒的硬件解决方案。该项目的成果可以很容易地用于许多具有挑战性的应用，如极端环境中的无线通信，高分辨率成像雷达，无线传感器/标签的跟踪和医疗诊断。该研究将对西弗吉尼亚理工大学的理工科课程设置产生建设性的影响。拟议的研究活动将支持研究生和本科生，并为他们提供电磁建模，天线，微波电路和无线系统领域的优秀研究机会。与当地高中学区的现有合作使高中学生/教师能够参与拟议的研究活动，并获得实际的工程经验。 该项目旨在通过为无线系统提供新颖的系统/电路解决方案，提供训练有素的学生，以及组织工业研讨会，短期课程和讲习班，影响当地工业的研究和教育方面。本计画之研究成果将透过期刊出版、会议报告、专利、计画网页、报纸、广播等方式传播，并提出一种低成本的宽带微波讯号时间反转架构。它利用频域中的迂回来避免时间上的高速模数转换，通过三个步骤：（i）“傅里叶变换”，以获得输入信号的离散频谱;（ii）“数字信号处理”，对步骤（i）中获得的频谱样本进行复共轭运算;以及（iii）“傅立叶逆变换”，以使用离散连续波元件来合成时间反演的信号。这种新颖的时间反转架构仅由常见的半导体元件，如振荡器，乘法器/混频器，带通滤波器，放大器和开关。因此，它体现了一个紧凑和低成本的片上系统实现。它的成功将为电磁波的时空聚焦建立一个有效和强大的硬件解决方案。具体而言，本研究有以下三个主要任务：第一，证明利用廉价电路实现微波信号时间反演的可行性;第二，研究具有大带宽和全向方向图的天线;第三，通过集成第一任务中的电路和第二任务中的天线来演示电磁波的时空聚焦

Time-reversal technique is capable of focusing waves in space and time. It has the potential to enable a wide range of revolutionary apparatuses, as shown by extensive prior research. Particularly, "time-reversal of acoustic signals" has been successfully implemented for underwater communication and sonar. However to date, no practical systems for "time-reversal of electromagnetic signals" have been reported; the major pertinent bottleneck is the expensive/bulky hardware required by time-reversing electromagnetic signals. This research proposes a novel frequency-domain architecture to time-reverse electromagnetic signals with low cost. It is expected to fundamentally resolve the "high-cost difficulty" associated with "time-reversal of electromagnetic signals," and in turn, to accomplish an efficient and robust hardware solution to space-time focusing of electromagnetic waves. This project's outcome can be readily employed in numerous challenging applications such as wireless communication in extreme environments, high-resolution imaging radars, tracking of wireless sensors/tags, and medical diagnosis. The proposed research will make constructive impacts on the science and engineering curriculum at West Virginia University Institute of Technology. The proposed research activities will support both graduate and undergraduate students and provide them with excellent research opportunities in the areas of electromagnetic modeling, antennas, microwave circuits, and wireless systems. Existing collaborations with local high school districts enables high school students/instructors to participate in the proposed research activities and gain practical engineering experiences. This project is intended to impact both research and educational aspects of local industries by providing novel system/circuit solutions for wireless systems, supplying exceptionally well-trained students, and organizing industrial seminars, short courses, and workshops. Research findings of this project will be disseminated by the means of journal publications, conference presentations, patents, project webpage, newspapers, and radio.This research proposes a novel architecture to time-reverse wideband microwave signals with low cost. It exploits detour in the frequency domain to avoid high-speed analog-to-digital conversion in time, via three steps: (i) "Fourier transform," to obtain discrete spectrum of the input signal; (ii) "Digital signal processing," to carry out complex conjugate operation for the spectral samples obtained in Step (i); and (iii) "Inverse Fourier transform," to synthesize the time-reversed signal using discrete continuous-wave elements. This novel time-reversal architecture is comprised solely of common semi-conductor components like oscillators, multipliers/mixers, band-pass-filters, amplifiers, and switches. As a result, it embodies a compact and low-cost system-on-a-chip implementation. Its success would establish an efficient and robust hardware solution to space-time focusing of electromagnetic waves. Specifically, this research has the following three major tasks: first, prove the feasibility of time-reversing microwave signals with inexpensive circuitries; second, investigate antennas with large bandwidth and omni-directional pattern; and third, demonstrate space-time focusing of electromagnetic waves by integrating the circuits from the first task and antennas from the second task