Experimental study of surface electromagnetic waves

The article deals with propagation of electromagnetic waves at microwave frequencies in the metal-insulator separation boundary. The waves were excited by different types of antennas. Paths of the waves' propagation were also different. The measurements were carried out both on a concrete floor and on a special path, which is metal-dielectric-air sandwich. The propagation paths had different shapes, ranging from straight tape and tape having hill-like bend. Basing on experimental results, it was concluded that in the propagation path a complex interference pattern exists, which is caused by spatial and surface waves. This indicates the presence of surface electromagnetic waves in the metal-insulator separating boundary. In particular, to reduce the complexity of waves, an indoor dipole antenna was used.

A method is proposed for surface wave's separation from received signal mix at the receiver. The method includes preliminary measurements of the background electromagnetic field strengths both without the underlying surface while the transmitter is turned off and with the underlying surface when the transmitter is turned off. These values allow further account and eliminate significant amount of the interfering signals. Experiments had shown that the suppression of parasitic background allows to register this wave which is similar to surface electromagnetic wave in its properties, namely, localization near the interface layer of two media and exponential fade with distance increase from the source along propagating surface.