Currents induced in the edge regions of FSS arrays

To study the influence of the edges on the currents induced in finite arrays used as frequency selective surfaces (FSS), large arrays of dual polarised elements have been modelled. The elements are rings, which provide azimuthal symmetry and do not restrict the current distributions. The current amplitudes fluctuate widely across the arrays, as do the orientations of nulls in the current distributions around the element circumference. Results for a sequence of arrays of increasing size illustrate how the currents eventually settle to the infinite case.