Abstract: In a multilayer filter, first and second resonant circuits are arranged in a direction crossing a stacking direction of a plurality of dielectric layers. An input/output portion includes an input/output port group including an unbalanced port and a pair of balanced ports or an input/output port group including two pairs of balanced ports. The second resonant circuit includes an inductor conductor, a first capacitor conductor, and a second capacitor conductor. The inductor conductor includes first and second ends. The first capacitor conductor is connected to the first end. The second capacitor conductor is connected to the second end. The second dielectric layer has a dielectric constant lower than that of the first dielectric layer. The first and second capacitor conductors are provided in the first dielectric layer. At least a part of the inductor conductor is provided in the second dielectric layer.

Abstract: In a multilayer filter, first to fourth resonant circuits are connected to an input/output portion. The input/output portion includes an input/output port group including an unbalanced port and a pair of balanced ports or an input/output port group including two pairs of balanced ports. Each of the first to fourth resonant circuits includes an inductor conductor and first and second capacitor conductors. The inductor conductor includes first and second ends. The first capacitor conductor is connected to the first end. The second capacitor conductor is connected to the second end. The second and third resonant circuits are magnetically coupled to each other. The second and third resonant circuits are arranged between the first resonant circuit and the fourth resonant circuit in a first direction. Each of first and second electrodes of a jump capacitor conductor is connected to the inductor conductors of the first and fourth resonant circuits.

Abstract: A filter circuit includes two ports, a first resonant circuit, and a second resonant circuit. The first resonant circuit is provided between the two ports in a circuit configuration and coupled with both of the two ports. The second resonant circuit is provided between the two ports in the circuit configuration and coupled with at least one of the two ports. Coupling of the second resonant circuit and the two ports is weaker than coupling of the first resonant circuit and the two ports.

Abstract: A filter device includes a ground conductor layer, at least one through hole electrically connected to the ground conductor layer, a first resonator conductor layer and a second resonator conductor layer arranged to sandwich the at least one through hole, and a stack. The first resonator conductor layer extends in a first direction becoming away from the at least one through hole, i.e., the ?X direction. The second resonator conductor layer extends in a second direction becoming away from the at least one through hole, i.e., the X direction.