Abstract: A multilayer bandpass filter includes a first capacitor electrode of a first stage LC parallel resonator, a second capacitor electrode of a second stage LC parallel resonator, and a third capacitor electrode of a third stage LC parallel resonator. Via electrodes and a line electrode define an inductor electrode of the first stage LC parallel resonator. Via electrodes and a line electrode define an inductor electrode of the second stage LC parallel resonator. Via electrodes and a line electrode define an inductor electrode of the third stage LC parallel resonator. The inductor electrodes of the three LC parallel resonators are arranged so loop planes thereof are disposed about a center axis extending in a stacking direction of dielectric layers. This permits setting of electromagnetic coupling between the LC parallel resonators of an input and an output stage, and allows a filter's attenuation characteristics to be freely set.

Abstract: In a laminated inductor element, outer electrodes and terminal electrodes are electrically connected by via holes, internal wiring lines, and end surface electrodes. The via holes on an upper surface side are provided immediately under the outer electrodes and in a non-magnetic ferrite layer. The via holes on a lower surface side are provided immediately above the terminal electrodes and in a non-magnetic ferrite layer. Since outermost layers are defined by the non-magnetic ferrite layers, a parasitic inductance is not increased, even if the outermost layers are provided with the via holes. In this case, the internal wiring lines are not routed on a surface of the element. Therefore, there is no complication of a wiring pattern, and it is possible to prevent an increase in a mounting area of the element.

Abstract: A multilayer bandpass filter includes a first capacitor electrode of a first stage LC parallel resonator, a second capacitor electrode of a second stage LC parallel resonator, and a third capacitor electrode of a third stage LC parallel resonator. Via electrodes and a line electrode define an inductor electrode of the first stage LC parallel resonator. Via electrodes and a line electrode define an inductor electrode of the second stage LC parallel resonator. Via electrodes and a line electrode define an inductor electrode of the third stage LC parallel resonator. The inductor electrodes of the three LC parallel resonators are arranged so loop planes thereof are disposed about a center axis extending in a stacking direction of dielectric layers. This permits setting of electromagnetic coupling between the LC parallel resonators of an input and an output stage, and allows a filter's attenuation characteristics to be freely set.

Abstract: In a directional coupler, sub-lines or main lines are electromagnetically coupled to each other to degrade isolation characteristics. A capacitor is located between the sub-lines or between the main lines to cause the isolation characteristics to have poles in order to improve the isolation characteristics of the directional coupler.

Abstract: A laminated balun transformer includes first line elements which are connected in series through a relay terminal, to constitute an unbalanced transmission line. Other line elements each constitute a balanced transmission lines. Strip lines are electromagnetically coupled to constitute a coupler. Similarly, other line elements are electromagnetically coupled to constitute a coupler. A ground terminal is connected to the balanced transmission lines, which are constituted by a pair of the line elements. Meanwhile, a shield terminal is connected to leading portions of shield electrodes. These two terminals are electrically independent of each other.

Abstract: A laminated balun transformer includes a third line element and a first line element which are electromagnetically coupled at a coupling portion to define a first coupler. A second line element and a fourth line element are electromagnetically coupled at a coupling portion to define a second coupler. When the length of a &lgr;/4 line element at a given characteristic impedance is L(0), the length of the coupling portion of the first and third line elements, which are electromagnetically coupled, is L(0)+&agr; and the length of the coupling portion of the second and fourth line elements, which are electromagnetically coupled, is L(0)−&bgr;, where &agr; and &bgr; satisfy the relationships &agr;>0, &bgr;>0, and &agr;=&bgr; or &agr;≠&bgr;.

Abstract: A laminated balun transformer includes a third line element and a first line element which are electromagnetically coupled at a coupling portion to define a first coupler. A second line element and a fourth line element are electromagnetically coupled at a coupling portion to define a second coupler. When the length of a &lgr;/4 line element at a given characteristic impedance is L(0), the length of the coupling portion of the first and third line elements, which are electromagnetically coupled, is L(0)+&agr; and the length of the coupling portion of the second and fourth line elements, which are electromagnetically coupled, is L(0)−&bgr;, where &agr; and &bgr; satisfy the relationships &agr;>0, &bgr;>0, and &agr;=&bgr; or &agr;≠&bgr;.