US Patent 7414493 System including a high directivity ultra-compact coupler

A system with an RFin terminal and an RFout terminal includes an output matching network. The system further includes a coupler having a thru arm connected between the output matching network and the RFout terminal, and a coupled arm connected to a detector circuit. The coupler further includes a stack of first and second dielectric materials having different dielectric constants. The stack of first and second dielectric materials extends over a top surface of a substrate. The thru arm and the coupled arm extend over the stack of first and second dielectric materials in the same plane parallel to a surface of the substrate.