Patent ID: 6847270

Claim:
A waveguide group branching filter comprising: a circular-to-square waveguide multistage transformer connected to an input port; a branch waveguide polarizer/branching filter connected to said circular-to-square waveguide multistage transformer; a first waveguide frequency filter connected to a branching end of said branch waveguide polarizer/branching filter; a rectangular waveguide H-plane T-branch circuit; a rectangular waveguide multistage transformer operably connecting one end of said branch waveguide polarizer/branching filter to said rectangular waveguide H-plane T-branch circuit; a second waveguide frequency filter connected to said rectangular waveguide H-plane T-branch circuit; and a third waveguide frequency filter connected to said rectangular waveguide H-plane T-branch circuit; wherein: a first radio wave of a first frequency band which has the polarization plane perpendicular to a branch plane of said waveguide polarizer/branching filter, a second radio wave of said first frequency band which has the polarization plane parallel to the branch plane of said branch waveguide polarizer/branching filter, and a third radio wave of a second frequency band higher than said first frequency band which has the same polarization plane as that of said first radio wave are incident to said input port; and said first radio wave is cut off by said first and second waveguide frequency filters and is emitted from said third waveguide frequency filter, said second radio wave is cut off by said rectangular waveguide multistage transformer and is emitted from said first waveguide frequency filter, and said third radio wave is cut off by said first and third waveguide frequency filters and is emitted from said second waveguide frequency filter.