Abstract: A directional coupler includes a laminate including a ground electrode substrate, a dielectric substrate that includes line electrodes thereon, a lead-out conductor substrate that includes lead-out conductors of the line electrodes, a ground electrode substrate, and a protection substrate. External electrodes for grounding, external electrodes for a main line, and external electrodes for a subordinate line are provided in the laminate. The inner line electrode and the outer line electrode preferably have a spiral or helical shape, and the corresponding currents are transmitted in the same direction through sections of these line electrodes that are adjacent and substantially parallel to each other.

Abstract: A directional coupler includes a laminate including a ground electrode substrate, a dielectric substrate that includes line electrodes thereon, a lead-out conductor substrate that includes lead-out conductors of the line electrodes, a ground electrode substrate, and a protection substrate. External electrodes for grounding, external electrodes for a main line, and external electrodes for a subordinate line are provided in the laminate. The inner line electrode and the outer line electrode preferably have a spiral or helical shape, and the corresponding currents are transmitted in the same direction through sections of these line electrodes that are adjacent and substantially parallel to each other.

Abstract: Two coil electrode patterns are formed on one surface of a plate containing a dielectric material. These coil electrode patterns are formed in a loop shape, and disposed in a magnetically connected state with each other. Input/output terminal patterns and earth terminal patterns are drawn out from the coil electrode patterns toward edges on different sides of the plate. The input/output terminal pattern and the earth terminal pattern of one coil electrode pattern are disposed at a selected distance from each other so as to provide a predetermined impedance. An earth electrode pattern is formed opposite the coil electrode patterns with the plate between them. Earth terminal patterns are connected to the earth electrode pattern. The earth terminal patterns of the earth electrode pattern are connected to the earth terminal patterns of the coil electrode patterns. A trimming electrode may be formed for adjusting the passing band frequency of the band-pass filter optionally.