Coupler device

The present invention is directed to a coupler that includes a coupler structure including at least one first transmission line disposed on a first major surface of a coupler dielectric substrate and at least one second transmission line disposed on a second major surface of the coupler dielectric substrate. The coupler structure includes four symmetric ports such that each port of the four symmetric ports is characterized by substantially identical impedance characteristics. A first ground plane structure is coupled to the coupler structure and including a first outer dielectric material and a first conductive exterior layer disposed substantially parallel to the first major surface. A second ground plane structure is coupled to the coupler structure and including a second outer dielectric material and a second conductive exterior layer disposed substantially parallel to the second major surface. A thermal path is disposed between the coupler structure and at least one of the first conductive exterior layer or second conductive exterior layer. The thermal path is characterized by a thermal resistance substantially within a range between 15 W/mK and 50 W/mK, such that the coupler has a power handling capability of more than 800 W per square inch of heat sink interface.