Millimeter wave fin-line reflection phase shifter

Claim 1

A millimeter wave reflection type phase shifter having first and second ports and operable over a given design frequency band comprising: a rectangular waveguide network including a leg section and first, second, third and fourth arm sections, said first and second arm sections connected to a first end of said leg section and together with said leg section comprising a first symmetric Y-junction with the free end of said first arm section being said first port of said device and the free end of said second arm section being said second port of said device, said third and fourth arm sections connected to a second end of said leg section and together with said leg section comprising a second symmetric Y-junction, said leg section and said arm sections having substantially planar top and bottom walls and having lateral walls extending between said top and bottom walls; a fin-line substrate having first and second opposed major surfaces disposed in said waveguide network with said major surfaces parallel to and spaced from said top and bottom walls and forming a septum extending laterally across said leg section and at least a portion of each of said arm sections; a conductive layer disposed on said first major surface of said substrate and leaving a central non-conductive slot therein, said slot extending along said leg section and portions of said first through fourth arm sections, said conductive layer being RF coupled to said lateral walls at least in said operating frequency band; a conductor disposed in the vicinity of said substrate extending parallel to and located either one of above or below said slot in said leg section; means for providing a short across said slot within said third arm section and within said fourth arm section to thereby provide the phase shift between said first and second ports.