A band-pass filter includes a first input/output port, a second input/output port, a first high-pass filter, a first low-pass filter, and a first stub resonator. The first stub resonator includes a first distributed constant line. The first low-pass filter is provided between the first input/output port and the first high-pass filter in the circuit configuration. The first distributed constant line has a first end connected to a first path connecting the first input/output port and the first low-pass filter, and a second end closest to a ground in the circuit configuration.

A branching filter includes a common port, a first signal port, a second signal port, a first filter, which is provided between the common port and the first signal port, that selectively passes a signal of a frequency within a first passband, a second filter, which is provided between the common port and the second signal port, that selectively passes a signal of a frequency within a second passband different from the first passband, and a capacitor that has a first end and a second end and connects the first filter and the second filter.

An electronic component includes a first and second inductor forming sections integrated with a stack, and a connection conductor layer connecting the first and second inductor forming sections inside the stack. In the first inductor forming section, two first through hole lines are connected to a wide portion of an inductor conductor layer, and two second through hole lines are connected to a narrow portion of the inductor conductor layer. In the second inductor forming section, two first through hole lines are connected to a wide portion of an inductor conductor layer, and two second through hole lines are connected to a narrow portion of the inductor conductor layer.

A multiplexer includes: a first terminal; a second terminal; a third terminal; a first filter connected between the first and second terminals, including a first capacitor, a first inductor, and one or more first acoustic wave resonators, and having a first passband; a second filter connected between the first and third terminals, including a second capacitor, a second inductor, and one or more second acoustic wave resonators, and having a second passband higher than the first passband; a substrate having a surface on which at least one first acoustic wave resonator of the one or more first acoustic wave resonators and at least one second acoustic wave resonator of the one or more second acoustic wave resonators are located; and a metal structure located on the surface and located between the at least one first acoustic wave resonator and the at least one second acoustic wave resonator.

A coupled resonator filter is disclosed. The coupled resonator filter is provided with high quality factor, and comprises: a first resonance unit, a second resonance unit and a main adjustment unit. In the present invention, the main adjustment unit is electrically connected between the first resonance unit and the second resonance unit, and comprises an adjustable capacitor. By changing a capacitance of the adjustable capacitor, a coupling coefficient between the first resonance unit and the second resonance unit is adjusted. As a result, the coupled resonator filter of the present invention included advantages of high controllability of the frequency bandwidth and high inhibition rate of noise signal.

A coupled resonator filter is disclosed. The coupled resonator filter is provided with high quality factor, and comprises: a first resonance unit, a second resonance unit and a main adjustment unit. In the present invention, the main adjustment unit is electrically connected between the first resonance unit and the second resonance unit, and comprises an adjustable capacitor. By changing a capacitance of the adjustable capacitor, a coupling coefficient between the first resonance unit and the second resonance unit is adjusted. As a result, the coupled resonator filter of the present invention included advantages of high controllability of the frequency bandwidth and high inhibition rate of noise signal.

An LC filter includes a first capacitor electrode connected to one end of a first via conductor and faces a first ground electrode in a laminating direction. A second capacitor electrode is connected to one end of a second via conductor and faces the first ground electrode in the laminating direction. A third capacitor electrode is connected to one end of a third via conductor and faces the first ground electrode in the laminating direction. A fourth capacitor electrode is connected to one end of a fourth via conductor and faces the first ground electrode in the laminating direction. The second capacitor electrode faces each of the first capacitor electrode, the third capacitor electrode, and the fourth capacitor electrode in a direction orthogonal or substantially orthogonal to the laminating direction.

An LC filter includes a first electrode connected to a first via conductor between two ends of the first via conductor, a second electrode connected to a second via conductor between two ends of the second via conductor, a third electrode connected to a third via conductor between two ends of the third via conductor, and a fourth electrode connected to a fourth via conductor between two ends of the fourth via conductor. In a plan view viewed from the laminating direction, the second via conductor and the fourth via conductor are disposed on two sides of a virtual line connecting the first via conductor and the third via conductor, respectively. The second electrode faces the first electrode and the third electrode.

A filter circuit includes a matching network having resistive and capacitive elements, and a transformer in the matching network. The transformer includes a primary side and a secondary side, and has at least one interwinding capacitance coupled from an input on the primary side to a non-inverting output on the secondary side.

A high frequency filter includes series arm resonators and parallel arm resonators as acoustic wave resonators and at least one inductor, wherein capacitive components of the acoustic wave resonators constitute an LPF and an HPF as hybrid filters with an inductor or with an inductor and a capacitor, and the at least one inductor includes inductors as mount component inductors.