This paper presents several novel designs of small form factor underwater radio antennas operating in the 2 MHz, 50 MHz and 2.4 GHz bands. These antennas efficiently excite surface electromagnetic waves (SEW) which propagate along the surface of seawater. The antenna operation is made possible due to implementation of an impedance matching enclosure, which is filled with de-ionized water. Enhanced coupling to surface electromagnetic waves is enabled by the enhancement of the electromagnetic field at the antenna apex. These features allow us to make antenna dimensions considerably smaller compared to typical free space designs. They also considerably improve coupling of electromagnetic energy to the surrounding seawater. Since SEW propagation length is considerably larger than the skin depth in seawater, this technique is useful for underwater broadband wireless communication. We conclude that the developed broadband underwater radio communication technique will be useful in networking of unmanned underwater vehicles.

中文翻译：

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宽带水下无线电通信技术在无人水下航行器中的应用

本文介绍了在2 MHz，50 MHz和2.4 GHz频段工作的小型水下无线电天线的几种新颖设计。这些天线有效地激发了沿海水表面传播的表面电磁波（SEW）。由于阻抗匹配外壳的实现，天线操作成为可能，该外壳充满了去离子水。通过增强天线顶点处的电磁场，可以增强与表面电磁波的耦合。与典型的自由空间设计相比，这些功能使我们能够使天线尺寸大大缩小。它们还大大改善了电磁能与周围海水的耦合。由于SEW的传播长度比海水中的表皮深度大得多，该技术对于水下宽带无线通信很有用。我们得出的结论是，开发的宽带水下无线电通信技术将对无人水下航行器的联网有用。