US Patent 11362407 Directional couplers with DC insulated input and output ports

A directional coupler may include a first coupled section comprising a first and a second coupled transmission lines, the first coupled transmission line having a first end coupled to an input port. The directional coupler may also include a second coupled section comprising a first and a second coupled transmission lines. The directional coupler may also include a third coupled section comprising a first and a second coupled transmission lines. The first coupled transmission line of the third coupled section has a first end coupled to a second end of the second coupled transmission line of the second coupled section and a second end coupled to an output port. The directional coupler may further include a delay section. A total electrical length of the first coupled section, the second coupled section, the third coupled section, and the delay section is about 90 degrees.