Three-dimensional focusing of broadband microwave beams by a layered photonic structure

Experiment and analysis confirm that a finite layered structure involving glass layers with broad strip metallizations can be characterized by broadband negative refractionlike behavior in three dimensions. The structure is further characterized as capable of 2:1 broadband focusing of near field radiation, with verified experimental focusing bandwidth of 1:5:1. This represents a significant improvement over the two-dimensional and narrow band focusing operation of current implementations of left-handed media. An electronic reconfigurable version is identified together with potential applications.