Patent ID: 8786380

Claim:
A polarization converter, comprising: an annular waveguide comprising an inner conductor having an outer surface and an outer conductor having an inner surface coaxial with the outer surface of the inner conductor; and a plurality of loading structures within the annular waveguide, the plurality of loading structures configured to form a plurality of regions within the annular waveguide including an alternating sequence of high phase shift regions and low phase shift regions along a direction of propagation of an electromagnetic wave, the electromagnetic wave having a frequency within a predetermined operating frequency band, wherein the plurality of loading structures, in combination, are configured to introduce a predetermined relative phase shift between orthogonally polarized first and second components of the electromagnetic wave, and the plurality of loading structures are further configured to cut off propagation of one or more higher order modes in the low phase shift regions of the annular waveguide over the operating frequency band.