The isolated port of a 0/90 degree coupler is terminated by a novel complex termination impedance circuit having a reactance. The absolute value of the reactance is at least two ohms. The coupler receives a signal on its input port, and outputs a first signal on its first output port and a second signal on its second output port. A first load is coupled to the first output port without an intervening matching network. A substantial impedance mismatch exists between the first output port and the first load. A second load is coupled to the second output port without an intervening matching network. A substantial impedance mismatch exists between the second output port and the second load. Despite the substantial impedance mismatches, the first and second signals have a phase difference in a range of from 88 degrees to 92 degrees while exhibiting an amplitude imbalance less than 2 dB.

A microstrip antenna has two feed points. The microstrip antenna includes a feeder circuit which is configured to feed, to the two feed points, electric signals whose phases are different by 90° from each other. The feeder circuit includes a Wilkinson coupler unit and a phase-shift unit each of which is formed as a lumped constant circuit.

This disclosure relates generally to directional couplers. In one embodiment, a directional coupler includes a first port, a second port, a third port, a first inductive element, a second inductive element, a first switchable path, and a second switchable path. The first inductive element is coupled between the first port and the second port, while the second inductive element is mutually coupled to the first inductive element. The first switchable path is configured to be opened and closed, wherein the first switchable path is coupled between a first location of the second inductive element and the third port. The second switchable path is configured to be opened and closed, wherein the second switchable path is coupled between a second location of the second inductive element and the third port. In this manner, a directivity of the directional coupler can be switched between a forward direction and a reverse direction.

A power dividing circuit includes an input port, a first microstrip line, a first transmission subcircuit, a second transmission subcircuit, and a matching element. The first transmission subcircuit is coupled to a first microstrip line first end, and the first transmission subcircuit includes a first output port and a first resonance unit. The second transmission subcircuit is coupled to a first microstrip line second end, and the second transmission subcircuit includes a second output port and a second resonance unit. The matching element is coupled between the first output port and the second output port, the matching element matches impedances between the first transmission subcircuit and the second transmission subcircuit. A power divider is also provided.

A communication module includes an input/output switch, a duplexer, a transmit filter, and a receive filter. In the duplexer, a second side is disposed at a position farther from the input/output switch than a first side in a second direction orthogonal to a first direction. Any one of the transmit filter and the receive filter is disposed adjacent to the input/output switch in the first direction.

Tunable, broadband directional coupler circuits employing one or more additional, switchable coupling circuits for controlling frequency response, and related methods. In exemplary aspects, the directional coupler includes one or more additional coupling circuits that each include an additional coupling line located adjacent to the primary coupling line and that can be selectively activated to change a frequency response of the directional coupler. When an additional coupling circuit is activated, its additional coupling line has the effect of extending the length of the primary coupling line through mutual inductance, thus changing the coupling frequency response of the directional coupler. The additional coupling circuit includes one or more switch(es) to allow for the selective coupling of its additional coupling line to the coupling and/or isolation ports of the directional coupler to selectively change and control the frequency response of the primary coupling line.

Tunable, broadband directional coupler circuits employing one or more additional, switchable coupling circuits for controlling frequency response, and related methods. In exemplary aspects, the directional coupler includes one or more additional coupling circuits that each include an additional coupling line located adjacent to the primary coupling line and that can be selectively activated to change a frequency response of the directional coupler. When an additional coupling circuit is activated, its additional coupling line has the effect of extending the length of the primary coupling line through mutual inductance, thus changing the coupling frequency response of the directional coupler. The additional coupling circuit includes one or more switch(es) to allow for the selective coupling of its additional coupling line to the coupling and/or isolation ports of the directional coupler to selectively change and control the frequency response of the primary coupling line.

A power combiner includes a planar figure-8 shaped primary winding and a planar figure-8 shaped secondary winding; wherein, the planar figure-8 shaped primary winding is substantially overlaid with the planar figure-8 shaped secondary winding. In addition, there is provided a radio frequency (RF) transmitter having a power combiner, where the power combiner includes a planar figure-8 shaped primary winding and a planar figure-8 shaped secondary winding, wherein the planar figure-8 shaped primary winding is substantially overlaid with the planar figure-8 shaped secondary winding.

A power combiner includes a planar figure-8 shaped primary winding and a planar figure-8 shaped secondary winding; wherein, the planar figure-8 shaped primary winding is substantially overlaid with the planar figure-8 shaped secondary winding. In addition, there is provided a radio frequency (RF) transmitter having a power combiner, where the power combiner includes a planar figure-8 shaped primary winding and a planar figure-8 shaped secondary winding, wherein the planar figure-8 shaped primary winding is substantially overlaid with the planar figure-8 shaped secondary winding.

There is provided a cable network device comprising an input associated with a plurality of outputs, wherein each output is connected to a respective microstrip directional coupler and each microstrip directional coupler is connected to at least one of the other microstrip directional couplers. The microstrip directional couplers form a series of microstrip directional couplers, with a last microstrip directional coupler in the series having its output port terminated by a resistive element. An isolated port of each microstrip directional coupler is in electrical communication with the upstream path.