Abstract:
We show that it is possible to realize a passive planar
reflector whose reflectivity (close to the resonant frequency of
the reflector structure) is larger than unity. This reflector is
strongly coupled to evanescent fields of external sources and most
effectively extracts power from them. Next, this power can be
launched into far zone if the surface of the reflector is perturbed
by some small passive scatterers. Used as electrically large
reflector antennas, such planar surfaces show superdirectivity
properties (the effective area is larger than the geometrical area
of the reflector) while there is no need for careful subwavelength
control over the amplitude and phase of the surface currents