SBIR Phase I: Novel Emergency Communication System for Mines

该小型企业创新研究（SBIR）第一阶段项目采用了一种新方法，用于在RF信号强烈衰减的情况下检测通信的时变场，例如在矿井、洞穴、隧道和密集建筑环境中。已知较低频率的电磁（EM）波或磁近场（MNF）能够穿透吸收介质到比较高频率的场更大的距离。矿井中使用各种通信手段。一些依赖于无线网络，其他依赖于导体的电气连续性（现任电线或泄漏馈线）？其可能在灾难中受损，而其它依赖于在低频下操作的非常大的高功率环形天线。然而，环形接收天线（基于法拉第？电感定律）在低频磁场中产生较小的电压，除非线圈匝数N和面积A的乘积相应增加。最近的证据表明，工程磁电（ME）设备（磁致伸缩和电活性材料的层压板）可以在较低的频率比环形天线更敏感。该项目旨在优化ME设备及其相关的电子和软件系统，作为矿山紧急情况下低频通信的接收器。该项目的更广泛影响/商业化潜力可扩展到地下水管，管道和隧道检查期间的通信。这些商业应用领域中的每一个都对系统的尺寸和重量、通信范围和信道容量提出了不同的要求。从更广泛的意义上说，该计划中针对的技术发展应该促进ME设备用于目前正在开发的其他应用的潜力，包括短距离无线功率传输（例如用于体内治疗，药物管理或健康监测），个人通信气泡和磁力测量。与线圈相比，工程ME设备提供简单、坚固的结构和相对容易的小尺寸制造。工程ME设备表现出的磁电耦合系数是许多数量级大于那些自然发生的ME材料。

This Small Business Innovation Research (SBIR) Phase I project takes a newapproach to detecting time-dependent fields for communication in cases where RFsignals are strongly attenuated, such as in mines, caves, tunnels, and dense building environments. It is known that lower-frequency electromagnetic (EM) waves or magnetic near fields (MNF) are able to penetrate absorbing media to greater distances than higher frequency fields. A variety of communication means are used in mines. Some rely on wireless networks , others depend on electrical continuity of conductors (incumbent electrical wiring or leaky-feeders) ? which can be compromised in a disaster, and others depend on very large high-power loop antennas operating at low frequency. However, loop receive antennas (based on Faraday?s law of induction) produce smaller voltages in lower-frequency fields unless the product of the number ofturns, N, and area, A, of the loop is correspondingly increased. Recent evidence suggests that engineered magneto-electric (ME) devices (laminates of magnetostrictive and electroactive materials) can be more sensitive than loop antennas at lower frequencies. This project aims to optimize ME devices as well as their associated electronic and software systems as receivers for low-frequency communications in mine emergencies.The broader impact/commercialization potential of this project extendsimmediately to communication during inspection of underground water mains, conduits, and tunnels. Each of these areas of commercial application place different demands on system size and weight, communication range and channel capacity. In a broader sense, the technical developments targeted in this program should advance the potential of ME devices for other applications presently under development, including short-range wireless power transfer (such as for in-vivo therapy, medication management, or health monitoring), personal communication bubbles, and magnetometry. Engineered ME devices offer advantages of simple, robust structure, and relative ease of fabrication atsmall dimensions compared to coils. Engineered ME devices exhibit magneto-electric coupling coefficients that are many orders of magnitude greater than those of naturally occurring ME materials.