A system for rotating polarization of radio frequency (RF) waves includes a flange configured to couple to a waveguide interface at a first side of the flange. The flange includes a recess at the first side of the flange, a rectangular cavity through the flange and located in the recess, and pins extending from the recess. The system further includes a plurality of shims configured for stacking in the recess. The shims each include a rectangular cavity and holes configured to receive the pins and position the plurality of shims in the recess such that the rectangular cavities form a spiral configured to rotate polarization of linearly-polarized RF waves received at the flange from a first polarization to a second polarization angularly rotated from the first polarization.

A system for rotating polarization of radio frequency (RF) waves includes a flange configured to couple to a waveguide interface at a first side of the flange. The flange includes a recess at the first side of the flange, a rectangular cavity through the flange and located in the recess, and pins extending from the recess. The system further includes a plurality of shims configured for stacking in the recess. The shims each include a rectangular cavity and holes configured to receive the pins and position the plurality of shims in the recess such that the rectangular cavities form a spiral configured to rotate polarization of linearly-polarized RF waves received at the flange from a first polarization to a second polarization angularly rotated from the first polarization.