A network transformer module includes a first magnetic element and a second magnetic element. The first magnetic element includes a first iron core and a first coil winding. The first coil winding is composed of a first wire and a second wire, and is wrapped 7 to 14 turns around the first iron core. The second magnetic element includes a second iron core and a second coil winding. The second coil winding is composed of a third wire and a fourth wire, and is wrapped 2 to 5 turns around the second iron core.

An isolation transformer includes a transformer core. First and second through-bores extend through the transformer core from a first surface to a second surface. Each through-bore has an elongated profile with at least a portion of the elongated profile providing a respective flat winding surface. The flat winding surfaces are spaced apart by a central portion of the transformer core. The transformer is wound with a six-wire cable having a central non-conductive core. First, second, third, fourth, fifth and sixth conductive wires are positioned around and adjacent to the central non-conductive core in a substantially equally spaced angular relationship. The second conductive wire is positioned between the first conductive wire and the third conductive wire; and the fifth conductive wire is positioned between the fourth conductive wire and the sixth conductive wire. The conductive wires are twisted about the central non-conductive core at a selected twist density.

An apparatus includes a carrier substrate, a ferrite core, a first set of wire windings, a second set of wire windings, a third set of wire windings, and a fourth set of wire windings. The ferrite core is attached to the carrier substrate. The first set of wire windings, the second set of wire windings, the third set of wire windings, and the fourth set of wire windings pass through the ferrite core and between the ferrite core and the carrier substrate to which the ferrite core is attached.

An apparatus includes a carrier substrate, a ferrite core, a first set of wire windings, a second set of wire windings, a third set of wire windings, and a fourth set of wire windings. The ferrite core is attached to the carrier substrate. The first set of wire windings, the second set of wire windings, the third set of wire windings, and the fourth set of wire windings pass through the ferrite core and between the ferrite core and the carrier substrate to which the ferrite core is attached.

PROBLEM: To provide a high-performance complex circuit, circuit device, circuit board, and communication device that support a wider band of frequencies. SOLUTION: A complex circuit includes a first diplexer that passes through the normal-phase signals of balanced signals and a second diplexer that passes through the reverse-phase signals of the balanced signals. A balun includes a low frequency band first balun element and a high frequency band second balun element. The first balun element and the second balun element respectively include a plurality of lines that are connected to the first diplexer and that carry signals occupying two different frequency bands and also respectively include a plurality of lines that are connected to the second diplexer and that carry signals occupying two different frequency bands. The lines form one pair of balanced lines, and the lines form another pair of balanced lines. Furthermore, the first balun element and the second balun element each include an unbalanced line.

PROBLEM: To provide a high-performance complex circuit, circuit device, circuit board, and communication device that support a wider band of frequencies. SOLUTION: A complex circuit includes a first diplexer that passes through the normal-phase signals of balanced signals and a second diplexer that passes through the reverse-phase signals of the balanced signals. A balun includes a low frequency band first balun element and a high frequency band second balun element. The first balun element and the second balun element respectively include a plurality of lines that are connected to the first diplexer and that carry signals occupying two different frequency bands and also respectively include a plurality of lines that are connected to the second diplexer and that carry signals occupying two different frequency bands. The lines form one pair of balanced lines, and the lines form another pair of balanced lines. Furthermore, the first balun element and the second balun element each include an unbalanced line.

PROBLEM: To provide a high-performance complex circuit, circuit device, circuit board, and communication device that support a wider band of frequencies.

SOLUTION: A complex circuit includes a first diplexer that passes through the normal-phase signals of balanced signals and a second diplexer that passes through the reverse-phase signals of the balanced signals. A balun includes a low frequency band first balun element and a high frequency band second balun element. The first balun element and the second balun element respectively include a plurality of lines that are connected to the first diplexer and that carry signals occupying two different frequency bands and also respectively include a plurality of lines that are connected to the second diplexer and that carry signals occupying two different frequency bands. The lines form one pair of balanced lines, and the lines form another pair of balanced lines. Furthermore, the first balun element and the second balun element each include an unbalanced line.

A transformer device includes a first and a second trace, a first and a second connection member, and a first input/output member. A second sub-trace of the first trace is coupled to a first sub-trace of the first trace at a first and a second area. The first connection member is coupled to the first and the second sub-trace. The first and a third sub-trace of the second trace are disposed in turn. A fourth sub-trace of the second trace is coupled to the third sub-trace at the first and the second area. The second and the fourth sub-trace are disposed in turn. The second connection member is coupled to the third and the fourth sub-trace. The first sub-trace includes first wires, and the first input/output member is coupled to the first wire which is located at an inner side among the first wires.

An apparatus includes a carrier substrate, a ferrite core, a first set of wire windings, a second set of wire windings, a third set of wire windings, and a fourth set of wire windings. The ferrite core is attached to the carrier substrate. The first set of wire windings, the second set of wire windings, the third set of wire windings, and the fourth set of wire windings pass through the ferrite core and between the ferrite core and the carrier substrate to which the ferrite core is attached.