Directional coupler

A directional coupler comprising:

• a main line;
• a sub-line electromagnetically coupled to the main line;
• a coupling terminal;
• a terminal circuit;
• a first switching circuit configured to selectively connect a first end of the sub-line to the coupling terminal or the terminal circuit;
• and
• a second switching circuit configured to selectively connect a second end of the sub-line to the coupling terminal or the terminal circuit,
• wherein the second switching circuit is configured to connect the second end of the sub-line to the terminal circuit when the first switching circuit connects the first end of the sub-line to the coupling terminal,
• wherein the second switching circuit is configured to connect the second end of the sub-line to the coupling terminal when the first switching circuit connects the first end of the sub-line to the terminal circuit, and
• wherein the first switching circuit is configured to:
• connect the first end of the sub-line to the coupling terminal at a different time than when the first switching circuit disconnects the first end of the sub-line from the terminal circuit, and
• disconnect the first end of the sub-line from the coupling terminal at a different time than when the first switching circuit connects the first end of the sub-line to the terminal circuit.