Patent ID: 7005937

Claim:
A surface mount circulator comprising: a laminar assembly having a transmission line conductor interposed between at least two insulating layers, the outer surface of each said insulating layer being metallized and said line conductor having at least two co-planar axes of symmetry, said line conductor further having at least three ports; said ports formed by a plurality of holes through said laminar assembly, each of said plurality of holes being positioned within said insulating regions and passing through said transmission line conductor; a ferrite positioned in proximity to said transmission line conductor; said plurality of holes being plated through with a conductive material, said conductive material in said plurality of holes being in electrical contact with said transmission line conductor and insulated from said metallization on said outer surfaces of said insulating layers; electrical contact pads formed by bisecting said plurality of holes, said plurality of bisected holes forming electrical contact pads with said transmission line conductor, said electrical contact pads forming low loss transition couplings at each of said locations where said transmission line conductor intersects said axes of symmetry of said transmission line conductor; and wherein the materials of said laminar assembly are selected such that there is a difference in coefficient of thermal expansion that causes said laminar assembly to exert axial pressure to bias said ferrite and said line conductor together.