A review of exact solutions for conversion of a surface wave into a propagating wave

In this paper, we summarize our recent theoretical and numerical studies of conversion of a surface wave to a propagating wave (and vice versa) with maximized conversion efficiency. We show that the exact solution for the homogeneous plane wave to surface wave conversion in a homogeneous medium by a point-wise lossless metasurface is restricted by Maxwell's equations. Such performance is possible only with approximations and implies some limitations, including impossibility to fully avoid unwanted scatterings. Nevertheless, an inhomogeneous plane wave can be converted into a surface wave perfectly, and it is described by an exact solution formed by a superposition of only two modes of the Floquet expansion. The results of the studies are expected to be of fundamental importance for leaky-wave antennas efficiency improvement. Besides, they can lead to novel applications in various research areas.