Planar phase-shifting structures for steerable DBS antennas

The authors describe the design and performance of planar phase shifting structures. A pattern of thin metallic shapes can provide a net inductive or capacitive susceptance to a propagating wave, which influences its phase (and amplitude). The pattern can be fabricated by etching a transparent copper-clad substrate, in much the same way as is done with printed circuit boards. This same basic printed planar susceptance technique has been used in the design of frequency-selective surfaces; the effect sought by the authors is (in circuit terms) that of a spatially-varying phase-shifter rather than a filter