Unit-Cell Geometry in Stripline Technology Featuring Sequential Band-Gaps Between Every Two Consecutive Modes

A novel geometry of unit cells relying on printed technology and featuring full dispersion diagram (DD) exhibiting an unusual large number of electromagnetic band-gaps (EBGs) is proposed. The printed patch consists of a filter-like geometry, meandered around the symmetry center of the unit cell and connected to the ground plane by three aligned vias, locally increasing the loading inductances; the multiple resonances shown by the structure determine the limits of the band-gaps. In particular, the DD of the unit cell presents an EBG between every two consecutive modes of propagation within the first eight modes in the case of one-directional propagation. The same phenomenon has been demonstrated for 2-D propagation, where four EBGs are proven to exist between the first five modes, in the case of arbitrarily directed propagation in the main plane of the structure. The 2-D scanning needed for building up the full DDs is realized by computer simulation with dedicated software. The small differences in band limits between the 1-D and 2-D cases reflect a small amount of anisotropy. The wide range of mono-modal behavior allows the structure to be used in applications requiring selective filtering, e.g., direct incorporation into antenna feeding systems, self-collimation, super lens, etc.