| 摘要 |
PROBLEM TO BE SOLVED: To provide a coupler that has excellent characteristics over a wide band, and is compact and low in height.SOLUTION: A coupler includes a main line, a sub line, an input port, an output port, a coupling port, and an ISO port on a multilayer substrate. The sub line is longer than the main line, which is arranged in a first layer. A first sub line part as a part of the sub line is arranged in a second layer below the first layer, and has its one end part connected to the coupling port. A second sub line part as the other part of the sub line is arranged in a third layer above the first layer, and has its one end part connected to the ISO port. The other end part of the first sub line part and the other end part of the second sub line part are connected by a via. Coupling parts are formed at the main line, the one end part of the first sub line part, and the one end part of the second sub line part respectively by arranging the main line, the part of the first sub line part, and the part of the second sub line part closely or one over another when viewed from a plane. Intermediate parts of the sub line extending between the coupling part of the first sub line part and the coupling part of the second sub line part are non-coupling parts, and the first and second sub line parts have their non-coupling parts made less in line width than their couling parts. |
