Stripline tapped-line hairpin filter

A stripline tapped-line filter comprising:

• a first dielectric substrate;
• a plurality of N U-shaped hairpin resonators, each being a half-wavelength open-circuited hairpin resonator, disposed alternately on first and second parallel planar surfaces of said first substrate, certain ones of said hairpin resonators located on said first surface and certain other ones of said hairpin resonators located on said second surface with said first substrate separating said certain ones of said hairpin resonators from said certain other ones of said hairpin resonators and said certain ones and said certain other ones of said hairpin resonators having noncongruent adjacent edges, each hairpin resonator positioned in a spaced parallel relationship with respect to an adjacent hairpin resonator located on an opposite one of said first and second surfaces such that each hairpin resonator is in a parallel coupled relationship with an adjacent hairpin resonator disposed on an opposite one of said first and second surfaces, each hairpin resonator including first and second spaced parallel members interconnected at one end and by a third member perpendicular to said first and second members, and the first and last hairpin resonators disposed on said first substrate each including an interconnected fourth member disposed on a respective one of said first and second surfaces to which a corresponding first and last hairpin resonator is disposed for respectively coupling a signal into and out of said hairpin resonators, said first hairpin resonator fourth member perpendicularly intersecting with said first hairpin resonator first member and extending outwardly along a corresponding one of said first and second surfaces towards one end of said first substrate and said last hairpin resonator fourth member perpendicularly intersecting with said last hairpin resonator second member and extending outwardly along a corresponding one of said first and second surfaces towards the other end of said first substrate;
• a second dielectric substrate having third and fourth surfaces substantially parallel to and coextensive with said first and second surfaces, said third surface located adjacent to said certain ones of said hairpin resonators;
• a third dielectric substrate having fifth and sixth surfaces substantially parallel to and coextensive with said first and second surfaces, said fifth surface located adjacent to said certain other ones of said hairpin resonators;
• a first groundplane having seventh and eighth surfaces substantially parallel to and coextensive with said third and fourth surfaces, said seventh surface mounted upon said fourth surface;
• and
• a second groundplane having ninth and tenth surfaces substantially parallel to and coextensive with said fifth and sixth surfaces, said ninth surface mounted upon said sixth surface.