All-Angle Scanning Leaky-Wave Antennas and Surface-Wave Routing by Reconfigurable Metasurfaces

Abstract: In this work, we show that propagating waves can be fully converted into surface waves and back using geometrically periodic arrays of simple electrically small metal elements loaded by adjustable reactive loads. The proposed approach allows the creation of all-angle scanning leaky-wave antennas with perfect or even superdirective aperture efficiency at all scan angles. Moreover, it is possible to co-design such leaky-wave antenna arrays with surface-wave waveguides that can guide the received power to the load or to another leaky-wave antenna section. That second section can either reradiate the received power into any direction or perform some other transformation of the reradiated wave front, for example, focusing the power at a point. These and other functionalities are realized by global optimization of the reactive loads of array elements. This global optimization, together with the use of arrays with a subwavelength geometrical period, allows proper control over both propagating and evanescent-field distributions, ensuring theoretically perfect performance at arbitrary scan angles. The proposed technique can be used in antenna engineering and in advanced designs of reconfigurable intelligent surfaces.