Millimeter wave translating device with changeable insert element

In a high frequency wave translating device including an input waveguide transmission line structure designed for conducting millimeter waves and an output coaxial transmission line structure, means coupling said input and output structure comprising,

• a housing which contains the input waveguide structure,
• a slot in the housing extending perpendicular to the input waveguide,
• an electrically conductive flat plate insert which fits into the slot and contains the output coaxial line structures,
• an opening through the plate transverse to the plane thereof, in registration with and forming a continuation of the input waveguide,
• a wave translating element mounted in said opening for coupling electrically with both the input and output structures by electrically connecting to the waveguide and to the center conductor of the coaxial line, and
• a high frequency wave choke defined by a coaxial cavity in the plate adjacent the opening between the opening and the output coaxial line structure, concentric with and along said output line for preventing millimeter waves conducted by the input structure from being conducted to the output structure,
• an electrically conductive ring plug in the coaxial cavity completing the choke coaxial cavity and partially defining the plate opening and
• an electrically conductive window plug in an edge of the plate completing the plate opening.