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 includes a first port, a second port, a path, a circuit part, and at least one cavity resonator. The path connects the first port and the second port. The circuit part is provided in the path. Each of the at least one cavity resonator is coupled with the path from an outside of the path in a circuit configuration. The first cavity resonator is coupled with the path between the first port and the circuit part. The second cavity resonator is coupled with the path between the second port and the circuit part.

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.

Abstract: A filter circuit includes a pair of balanced input ports, a pair of balanced output ports, first and second resonators provided in parallel between the pair of balanced input ports and the pair of balanced output ports in a circuit configuration, a first capacitor connected in parallel to the first resonator, and a second capacitor connected in parallel to the second resonator. The first and second resonators are magnetically coupled to each other and electrically connected to each other. The first and second capacitors are not electrically connected to ground.

Abstract: A filter circuit includes a pair of balanced input ports, a pair of balanced output ports, and first and second resonators provided in parallel between the pair of balanced input ports and the pair of balanced output ports in a circuit configuration, the first and second resonators being magnetically coupled to each other. Between the first resonator and the second resonator, a capacitor is present but no inductor is present in the circuit configuration.

Abstract: A balun includes first to fourth lines and a stack. A plurality of first conductor layers forming the first and third lines are located in a first region in the stack. A plurality of second conductor layers forming the second and fourth lines are located in a second region in the stack. A ground conductor layer is located closer to the second region than to the first region. The plurality of second conductor layers include a conductor layer pair where a distance between two conductor layers is smallest.

Abstract: A balun includes first to fourth lines and a stack. A plurality of first conductor layers forming the first and third lines are located in a first region in the stack. A plurality of second conductor layers forming the second and fourth lines are located in a second region in the stack. A ground conductor layer is located closer to the second region than to the first region. The plurality of second conductor layers include a conductor layer pair where a distance between two conductor layers is smallest.

Abstract: An antenna system includes an antenna substrate, and an antenna element mounted on the antenna substrate. The antenna substrate includes a substrate body, a first ground layer, a feed line, and a first radiation element. The feed line includes a first connection. The first radiation element includes a width-changing portion and a second connection. The antenna element includes an element body, a first terminal, a second terminal, and a second radiation element. The second radiation element is provided in the element body and connects the first terminal and the second terminal. The first terminal is connected to the first connection. The second terminal is connected to the second connection.

Abstract: An antenna system includes an antenna substrate, and an antenna element mounted on the antenna substrate. The antenna substrate includes a substrate body, a first ground layer, a feed line, and a first radiation element. The feed line includes a first connection. The first radiation element includes a width-changing portion and a second connection. The antenna element includes an element body, a first terminal, a second terminal, and a second radiation element. The second radiation element is provided in the element body and connects the first terminal and the second terminal. The first terminal is connected to the first connection. The second terminal is connected to the second connection.

Abstract: The auxiliary ground layer is a part in which the main line and the sub line do not overlap in the lamination direction and is disposed to face a part in which a distance from the first ground layer and a distance from the second ground layer are different in the lamination direction. When a longer distance is set as a first distance a and a shorter distance is set as a second distance b between a distance between the non-overlapping part and the first ground layer and a distance between the non-overlapping part and the second ground layer, and a third distance between the non-overlapping part and the auxiliary ground layer is set as c, the relationship of a>c?b is satisfied.

Abstract: The element body includes a main line; a first sub line and a second sub line; a pair of ground layers that are disposed to face each other at positions at which the main line, the first sub line, and the second sub line are interposed in a stacking direction of the plurality of insulator layers; a phase control circuit that is connected between the first sub line and the second sub line and is disposed at a position at which one ground layer is interposed between the first sub line and the second sub line in the stacking direction; and a connection line that connects the first sub line and the second sub line to the phase control circuit. The connection line is surrounded by at least one of one ground layer and a conductor having the same potential as the ground layer when viewed in the stacking direction.

Abstract: A directional coupler includes a first to a fourth port, a main line connecting the first port and the second port, a first and a second subline section configured to be electromagnetically coupled to the main line, and a phase shifter. The first subline section, the phase shifter, and the second subline section are arranged in this order in series between the third port and the fourth port. The phase shifter outputs a signal that is phase-delayed relative to an input signal. The phase delay amount of the output signal of the phase shifter relative to the input signal increases with increasing frequency of the input signal. A frequency twice as high as the frequency of the input signal at which the phase delay amount is 90 degrees is lower than the frequency of the input signal at which the phase delay amount is 180 degrees.

Abstract: An antenna element is provided with a substrate made of a dielectric body, first to third terminal electrodes formed on a bottom surface of the substrate, a helical coil pattern that is formed in the inside of the substrate, a first lead pattern connected to one end of the helical coil pattern or near the one end, a second lead pattern connected to the other end of the helical coil pattern or near the other end, a first through-hole conductor that connects the first terminal electrode and the first lead pattern, a second through-hole conductor that connects the second terminal electrode and the second lead pattern, and a third through-hole conductor that connects the third terminal electrode and the one end of the helical coil pattern.

Abstract: The auxiliary ground layer is a part in which the main line and the sub line do not overlap in the lamination direction and is disposed to face a part in which a distance from the first ground layer and a distance from the second ground layer are different in the lamination direction. When a longer distance is set as a first distance a and a shorter distance is set as a second distance b between a distance between the non-overlapping part and the first ground layer and a distance between the non-overlapping part and the second ground layer, and a third distance between the non-overlapping part and the auxiliary ground layer is set as c, the relationship of a>c?b is satisfied.

Abstract: The element body includes a main line; a first sub line and a second sub line; a pair of ground layers that are disposed to face each other at positions at which the main line, the first sub line, and the second sub line are interposed in a stacking direction of the plurality of insulator layers; a phase control circuit that is connected between the first sub line and the second sub line and is disposed at a position at which one ground layer is interposed between the first sub line and the second sub line in the stacking direction; and a connection line that connects the first sub line and the second sub line to the phase control circuit. The connection line is surrounded by at least one of one ground layer and a conductor having the same potential as the ground layer when viewed in the stacking direction.

Abstract: A directional coupler includes: a first to a fourth port; a main line connecting the first and second ports; a first to a fourth subline section electromagnetically coupled to the main line; a first to a third matching section; and a stack. The first subline, first matching, third subline, third matching, fourth subline, second matching, and second subline sections are arranged in this order between the third and fourth port. The first and second matching sections include an inductor connecting two subline sections located on opposite sides of the matching section. Each of one or more conductor layers used to form the inductor includes two connection portions for electrical connection to respective other elements, and a line portion connecting the two connection portions. The inductor excluding the connection portions does not include potions that overlap each other when viewed in the stacking direction of the stack.

Abstract: A directional coupler includes a first to a fourth port, a main line connecting the first port and the second port, a first and a second subline section configured to be electromagnetically coupled to the main line, and a phase shifter. The first subline section, the phase shifter, and the second subline section are arranged in this order in series between the third port and the fourth port. The phase shifter outputs a signal that is phase-delayed relative to an input signal. The phase delay amount of the output signal of the phase shifter relative to the input signal increases with increasing frequency of the input signal. A frequency twice as high as the frequency of the input signal at which the phase delay amount is 90 degrees is lower than the frequency of the input signal at which the phase delay amount is 180 degrees.

Abstract: A directional coupler includes: a first to a fourth port; a main line connecting the first and second ports; a first to a fourth subline section electromagnetically coupled to the main line; a first to a third matching section; and a stack. The first subline, first matching, third subline, third matching, fourth subline, second matching, and second subline sections are arranged in this order between the third and fourth port. The first and second matching sections include an inductor connecting two subline sections located on opposite sides of the matching section. Each of one or more conductor layers used to form the inductor includes two connection portions for electrical connection to respective other elements, and a line portion connecting the two connection portions. The inductor excluding the connection portions does not include portions that overlap each other when viewed in the stacking direction of the stack.