A Novel Dual-Mode Dual-Polarized Circular Waveguide Feed Excited by Concentrically Shorted Ring Patches

There are a number of applications where an adaptive dual-mode dual-polarized reflector antenna feed is required, such that the mode excitation and polarization can be controlled externally. This paper presents one such feed. The modes are excited by two concentric shorted microstrip ring patches placed at the bottom end of an open-ended circular waveguide. It is shown that the proposed feed is capable of producing two perpendicular polarizations within a single hardware with excellent isolation between the excitation ports. A prototype antenna is fabricated and tested. The measured results satisfactorily validate the numerical ones.