Dual band antenna feed using an embedded waveguide structure

Abstract

A dual band antenna feed is made with an embedded waveguide structure to enable combining of Ka and Ku band signals without the need for an additional cavity-type filter. The antenna feed includes a Ka and Ku band interface section ( ) with two Ka band vertical polarization waveguide sections ( ) and ( ), and a single Ku band waveguide section ( ) which carries both vertical and horizontal polarization Ku band signals. The opposing walls ( ) of the Ku band waveguide ( ) carrying the vertical polarization Ku band signals are transitioned to step down from an input section ( ) to successively smaller dimensioned sections ( ), and then to step back up in successively larger dimensioned sections ( ) to an output section ( ). The two Ka band sections ( ) are fed into openings in Ku band section.( ), on opposite sides of the opening for the Ku band transition section ( ). The output section ( ) then provides a combined Ka band vertical and Ku band horizontal and vertical signals. With the Ka-band waveguides ( ) having ports ( ) facing the antenna port for radiation on opposite sides of the Ku-band section ( ) port, sufficient isolation will be provided between the Ka and Ku band signals without requiring an additional filter. A dielectric insert (FIG. A) may be included to improve performance characteristics of the antenna feed.