Coupled strip line circuit

A strip line apparatus, comprising;

• a coplanar, strip line having a central dielectric layer with conductors etched in either side thereof, said strip line folded through a 180.degree. bend of said central
• dielectric layer, and having two pairs of outer sandwiching dielectric layers with ground planes etched on the outer surfaces thereof, one pair of said outer layers extending from each end of said strip line opposite said bend to the point at which said bend begins;
• a coplanar center holding plate sandwiched between the folded ends of said strip line, said plate having a curved ground plane extension at one end facing said bend, said extension having a plurality of axially separated conductor channels disposed therein and receiving said second dielectric layer conductors facing inward from said bend;
• a pair of outer holding plates sandwiching said folded strip line coextensive with said outer dielectric layers, the end of each said plate facing said bend having one side of an attachment;
• and
• a means for enclosing said bend, said means having a curved interior surface having a plurality of axially separated conductor channels disposed therein and receiving said central layer conductors facing outward from said bend and having the mating side of said attachment for fixed engagement with said outer holding plates.

A method for fabricating a folded strip line having a lateral centerline, comprising:

• folding a coplanar strip line, having a center dielectric layer with conductors etched in either side thereof and a pair of outer sandwiching dielectric layers extending between the opposite ends of said strip line and a point equidistant from and on each side of said lateral centerline, sandwiching a center holding plate having a curved extension containing conductor channels, juxtaposing said central dielectric layer with said extension, and disposing said conductors on the inside of said bend in said extension channels;
• sandwiching said strip line folded about said center holding plate between two planar outer holding plates having connection means in their respective ends proximate to said strip line bend;
• and
• rigidly enclosing said strip line bend with a ground plane cover having a mating curved interior surface with channels overlaying juxtaposed conductors on the outside of said bend.

A method for fabricating a coupled, stacked strip line from a coplanar, strip line having a lateral centerline comprising:

• positioning a center holding plate having a curved ground plane extension at one end, relative to a coplanar, strip line such that the longitudinal centerlines of said plate and said strip line coincide, said extension having conductor channels disposed therein, and said strip line having a center dielectric layer with conductors etched in either side thereof and a pair of outer sandwiching dielectric layers extending between the opposite ends of said strip line and a point equidistant from and on each side of said lateral centerline;
• folding said coplanar, strip line through a curved bend about said lateral centerline, said center dielectric disposed in juxtaposition with said curved extension, said conductors on the side of said center dielectric layer facing said curved extension disposed in said conductor channels;
• sandwiching said strip line folded about said center holding plate between two planar outer holding plates having connection means in their respective ends proximate to said strip line bend;
• enclosing said strip line bend with a ground plane cover having a curved interior surface with conductor channels disposed therein, said channels receiving said conductors on the side of said center dielectric layer facing said cover, said cover having separated, coplanar walls extending diametrically on opposite sides of the opening of and normal to said curved interior surface, said walls having connection means for mating with the juxtaposed connection means in the respective ends of said planar outer holding plates;
• and
• rigidly engaging said juxtaposed connection means in said ground plane cover and the ends of said planar outer holding plates.