The Boeing Company
Low-profile rectangular to circular transition

Abstract:

A low-profile apparatus for transitioning circular polarized electromagnetic waves to linear polarized electromagnetic waves when moving in a first direction and transitioning linear polarized electromagnetic waves to circular polarized electromagnetic waves when moving in a second direction. The apparatus includes a substrate with an electrical path positioned within the substrate. A first antenna element attached to the substrate is capacitively coupled to the electrical path and a second antenna element attached to the substrate is capacitively coupled to the electrical path. The apparatus includes a ground plane and electromagnetic waves propagate along the electrical path in a transverse electromagnetic mode. The first antenna element may be positioned within an interior of a first waveguide and the second antenna element may be positioned within an interior of a second waveguide. The first waveguide may have a circular cross-section and the second waveguide may have a rectangular cross-section.