Patent ID: 7646261

Claim:
A coupler structure comprising: a first port, a second port, a third port, and a fourth port accessible via an exterior of the coupler structure; L first transmission line layers disposed in the coupler structure, each first transmission line layer including a first transmission line conforming to a predetermined geometric configuration, the first transmission line being disposed on a first dielectric material between the first port and the second port, L being an integer; and M second transmission line layers disposed in alternating layers with the L first transmission line layers to form a total of N transmission line layers, M and N being integers with N being greater than or equal to three, each second transmission line layer including a second transmission line substantially conforming to the predetermined geometric configuration, the second transmission line being disposed on a second dielectric material between the third port and the fourth port, each second transmission line being disposed in a predetermined position relative to a corresponding first transmission line within the structure, the coupler structure being characterized by a volume, the volume being a function of N and the predetermined geometric configuration for a selected coupling constant, the volume being inversely proportional to N over a first range of values for N.