The ultralow-frequency/very-low-frequency (ULF/VLF) band communication is stable and worldwide, which can penetrate into sea or underground with slight loss. It plays an irreplaceable role in oceanic great-depth communication, distant navigation, and geologic examination. In a conventional ULF/VLF transmission system, in order to effectively emit electromagnetic (EM) waves, the length of the transmitter should be close to the wavelength of the radiation signals. As a result, there are problems of complex structure, huge volume, and large power consumption in conventional LF transmitting system. Therefore, this work introduced a mechanical ULF/VLF transmitter designed with mechanically rotating electret to greatly reduce the size, and a generated magnetic field model based on finite-element method (FEM) is established to carry out the relevant analysis. The characteristics of the magnetic signals generated by electret-based transmitter such as direction and frequency are studied in detail. At the same time, the influence of relevant parameters such as size, rotation speed, electret material, and the number of layers on the magnetic signals is analyzed as well. What is more, the effect of lossy media and the propagation distance on the transmitter’s performance are also discussed. This work will lay the foundation for future system tests involving the implementation of efficient, small form-factor, mechanically actuated LF transmitters.

中文翻译：

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基于旋转驻极体的新型低频电磁信号变送器的模型与设计

超低频/超低频（ULF / VLF）频段通信稳定且遍及全球，可渗透到海洋或地下，而造成的损失很小。它在海洋深层通信，远距离导航和地质检查中发挥着不可替代的作用。在常规的ULF / VLF传输系统中，为了有效地发射电磁（EM）波，发射器的长度应接近辐射信号的波长。结果，在传统的LF发射系统中存在结构复杂，体积大和功耗大的问题。因此，这项工作引入了一种机械式ULF / VLF变送器，该变送器设计有机械旋转的驻极体，可以大大减小尺寸，建立了基于有限元法（FEM）的磁场模型进行相关分析。详细研究了驻极体发射器产生的磁信号的特性，例如方向和频率。同时，还分析了尺寸，转速，驻极体材料和层数等相关参数对磁信号的影响。此外，还讨论了有损媒体和传播距离对发射机性能的影响。这项工作将为以后的系统测试奠定基础，包括实现高效，小尺寸，机械驱动的LF发射器。详细研究了驻极体发射器产生的磁信号的特性，例如方向和频率。同时，还分析了尺寸，转速，驻极体材料和层数等相关参数对磁信号的影响。此外，还讨论了有损媒体和传播距离对发射机性能的影响。这项工作将为以后的系统测试奠定基础，包括实现高效，小尺寸，机械驱动的LF发射器。详细研究了驻极体发射器产生的磁信号的特性，例如方向和频率。同时，还分析了尺寸，转速，驻极体材料和层数等相关参数对磁信号的影响。此外，还讨论了有损媒体和传播距离对发射机性能的影响。这项工作将为以后的系统测试奠定基础，包括实现高效，小尺寸，机械驱动的LF发射器。还讨论了有损媒体和传播距离对发射机性能的影响。这项工作将为以后的系统测试奠定基础，包括实现高效，小尺寸，机械驱动的LF发射器。还讨论了有损媒体和传播距离对发射机性能的影响。这项工作将为以后的系统测试奠定基础，包括实现高效，小尺寸，机械驱动的LF发射器。