I. Introduction
Frequency selective surfaces are spatial filters that can split incident waves according to their frequencies. The FSS presented here is a high-pass filter designed to reflect signals below 30 GHz and transmit signals above 37.5 GHz. An FSS usually consists of elements arranged at the grid points of a uniform grid. The chosen element determines the behavior of the FSS [1]. However, most elements allow only a relatively small bandwidth. For certain practical applications such as the use in ground station antennas for scientific space missions, this bandwidth is sufficient [2]. However, there are also elements that allow a wider bandwidth. Here, the presented FSS shall consist of hexagon ring elements. Usually, identical elements are used at the grid points of an FSS. In the following, a method is presented in which the hexagon elements used are individually designed. This allows the locally occurring angle of incidence to be taken into account, as well as measures to achieve a polarization-independent behavior. This allows an application with circular (or any other) polarization in a divergent radiation field.