Low cross polarization and broad bandwidth

Claim 1

A microwave antenna/downconverter suitable for use by subscription television subscribers to deliver selected orthogonally polarized microwave signals to downconverter electronics, comprising; a planar electrically conductive member having first and second sides, a housing defining a chamber formed on said second side of said planar electrically conductive member for accommodating said downconverter electronics: an electrically conductive reflector cup formed on said first side of said planar electrically conductive member and defining an axis, said cup having a centrally located grounding post; a first electrically conductive receive disc for receiving said microwave signals, said disc axially spaced from said planar electrically conductive member within said reflector cup and centrally mounted to said grounding post; a second electrically conductive receive disc axially spaced from said planar electrically conductive member within said reflector cup and coupled to said around post at an axial spacing and radius different from said first receive disc; said second receive disc additionally comprising a pair of diametrically opposed wings extending to the perimeter of said reflector cup; a dielectric wafer disposed across said cut to enclose said first and second receive discs; an axially oriented electrically conductive probe shield defining a cavity extending from said chamber through said planar electrically conductive member to a point radially inward from the perimeter of said first receive disc; an electrically conductive probe centrally located within said cavity and electrically isolated from said probe shield directly coupling said first receive disc to said downconverter electronics through said probe shield; and a side lobe suppression rim formed by axially extending said reflector cup beyond said first and second receive discs and said dielectric wafer.