A directional coupler includes a main line, a sub line electromagnetically coupled to the main line, a coupling output terminal, a first filter connected to one end of the sub line, and a second filter connected to the one end of the sub line and the coupling output terminal and having a pass band different from that of the first filter. The first filter and the second filter are constituent elements of a multiplexer. The first filter is terminated.

A method of operating a reconfigurable quadrature coupler is disclosed. The method includes determining a first switchable impedance to provide a second port reflection coefficient by operating a coupled port transformer, which coupled port transformer is coupled to a second port having a coupled port transmission line connected to a first transistor; determining a second switchable impedance to provide a third port reflection coefficient by operating an isolation port transformer, which isolation port transformer is coupled to a third port having an isolation port transmission line connected to a second transistor; and determining a fourth switchable impedance to provide a fourth port reflection coefficient by operating a through port transformer, which through port transformer is coupled to a fourth port having a through port transmission line connected to a third transistor, and switching on or off selected ones of the first, second, and third transistors by operating a controller.

A directional coupler (1) includes a substrate (10), a main line (20) formed directly or indirectly on the substrate (10), sub-lines (21, 22 and 23) at least part of each of which is formed directly or indirectly on the substrate (10) along the main line (20), a switch (30) switching connections among end portions of the plurality of sub-lines (21, 22 and 23), and detection output terminals (FWD and REV) connected to the sub-line (21), wherein, when looking at the substrate (10) in plan, the end portions of the sub-lines (21, 22 and 23) are disposed on the opposite side to the detection output terminals (FWD and REV) relative to the main line (20), and the sub-line (21) to which the detection output terminals (FWD and REV) are connected is overlapped with or surrounded by the sub-lines (22 and 23).

A branch-line coupler of reduced size but comparable performance includes a first transmission line, a second transmission line, a first bent transmission line, and a second bent transmission line. The first transmission line includes a first strip transmission line, a first branch transmission line, and a second branch transmission line. The first strip transmission line extends along a predetermined direction, the first and second branch transmission lines being slotted. The first and second branch transmission lines are symmetrical around a first axis and around a second orthogonally-disposed axis. The first bent transmission line is electrically connected to the terminals of the first and second transmission lines on one side, and the second bent transmission line is electrically connected to the terminals of the first and second transmission lines on the other side.

A branch-line coupler of reduced size but comparable performance includes a first transmission line, a second transmission line, a first bent transmission line, and a second bent transmission line. The first transmission line includes a first strip transmission line, a first branch transmission line, and a second branch transmission line. The first strip transmission line extends along a predetermined direction, the first and second branch transmission lines being slotted. The first and second branch transmission lines are symmetrical around a first axis and around a second orthogonally-disposed axis. The first bent transmission line is electrically connected to the terminals of the first and second transmission lines on one side, and the second bent transmission line is electrically connected to the terminals of the first and second transmission lines on the other side.

A coupler module includes a coupler component formed with a main line and a sub-line that configure a directional coupler, and a module substrate on which the coupler component is mounted and on which a wiring conductor coupled in series with the main line is formed. At least a part of the wiring conductor is along the main line in plan view of the module substrate, and a direction of a main signal flowing through the main line and a direction of the main signal flowing through the part of the wiring conductor are opposite to each other.

A dual-frequency band coupled line directional coupler is configured to provide an enhanced insertion loss level. The directional coupler includes an input port, an output port, a coupled port, a termination port, and a capacitor element. A first track connects the input port to the output port and a second track, which may be substantially parallel to the first track, connects the termination port to the coupled port. A spacing between the capacitor element and the first track is configured to provide the enhanced insertion loss level between the input port and the output port.

A dual-frequency band coupled line directional coupler is configured to provide an enhanced insertion loss level. The directional coupler includes an input port, an output port, a coupled port, a termination port, and a capacitor element. A first track connects the input port to the output port and a second track, which may be substantially parallel to the first track, connects the termination port to the coupled port. A spacing between the capacitor element and the first track is configured to provide the enhanced insertion loss level between the input port and the output port.

There is provided an ultra-small size broadband coupler. A Lange coupler according to an embodiment includes: first lines which are formed in a spiral shape, and have a first port and a second port formed at one end thereof and have connection ends formed at the other end thereof; and second lines which are formed in a spiral shape, and have connection ends formed at one end thereof to be connected to the connection ends of the first lines, and have a third port and a fourth port formed at the other end thereof. Accordingly, the Lange coupler maintains broadband characteristics while minimizing its area, so that it is possible to design a small component for mobile communication and to noticeably reduce an insertion loss.

A directional coupler includes a substrate, a main line, a first sub-line, and a ground conductor. The main line includes a first conductor line and a second conductor line electrically connected to each other. The first sub-line includes a third conductor line. The first conductor line and the second conductor line are able to be electromagnetically coupled to the third conductor line. The first conductor line has a first edge and a second edge. The second conductor line has a third edge and a fourth edge. The third conductor line has a fifth edge and a sixth edge. The first conductor line, the second conductor line, and the third conductor line are arranged in such a manner that the first edge, the fifth edge, the third edge, the second edge, the sixth edge, and the fourth edge are arranged in this order when the substrate is viewed in plan.