of a dual multilevel antenna fig9 shows return losses l r in gsm 9 1 and dcs 9 2 typically under u2212 14 db which is equivalent to swr lt 1 5 so that the antenna is well adapted in both operation bands 890 mhz 960 mhz and 1710 mhz 1880 mhz radiation diagrams in the vertical 10 1 and 10 3 and the horizontal plane 10 2 and 10 4 for both bands are shown in fig1 it can be seen clearly that both antennae radiate using a main lobe in the direction perpendicular to the antenna 10 1 and 10 3 and that in the horizontal plane 10 2 and 10 4 both diagrams are sectorial with a typical beam width at 3 db of 65 u00b0 typical directivity d in both bands is d gt 7 db this model consists of a multilevel antenna in a monopole configuration shown in fig1 for wireless communications systems for indoors or in local access environments using radio the antenna operates in a similar manner simultaneously for the bands 1880 mhz 1930 mhz and 3400 mhz 3600 mhz such as in installations with the system dect the multilevel structure is formed by three or five triangles see fig1 and 3 6 to which may be added an inductive loop 11 1 the antenna presents an omnidirectional radiation diagram in the horizontal plane and is conceived mainly for but not limited to mounting on roof or floor the multilevel structure is printed on a rogers u00ae ro4003 dielectric substrate 11 2 of 5 5 cm width 4 9 cm height and 0 8 mm thickness and with a dielectric permittivity equal to 3 38 the multilevel element consists of.