WIDEBAND PLANAR SPIRAL ANTENNA WITH PERIPHERAL FEEDING

The topology of a planar Archimedes spiral antenna with a small number of turns is presented. Its main feature is the peripheral feeding of the spiral, which does not violate the planarity of the structure. On the basis of numerical simulation, the main electrodynamic characteristics for several antenna designs, differing in the number of turns, including the constant and variable width of the tape of the spiral element, are obtained, compared and discussed. The results of the numerical analysis showed that the relative bandwidth defined by the VSWR at the antenna input and by the directivity, reach from 75 to 120 percent.