A filter includes an input terminal, an output terminal, a ground terminal, a first capacitor and a second capacitor that are connected in series between the input terminal and the output terminal, a capacitive element that is connected in parallel to the first capacitor and the second capacitor between the input terminal and the output terminal, and has a Q factor that is smaller than a Q factor of the first capacitor and is smaller than a Q factor of the second capacitor, and an inductor that has a first end and a second end, the first end being coupled to a node that is provided between the first capacitor and the second capacitor and that is coupled to the capacitive element through the first capacitor and the second capacitor, the second end being coupled to the ground terminal.

A filter includes an input terminal, an output terminal, a first ground terminal, a second ground terminal, a first inductor having a first end coupled to a first node in a path between the input terminal and the output terminal and a second end coupled to a second node, a second inductor having a first end coupled to the second node and a second end coupled to the first ground terminal, and a third inductor having a first end coupled to the second node and a second end coupled to the second ground terminal.

A filter circuit (1) includes a first transmission line (11), a second transmission line (12) which has an electrical length set to ½ of an electrical length of the first transmission line, a first capacitor (21), a second capacitor (22), and a third capacitor (23). Capacitances of the first capacitor, the second capacitor, and the third capacitor are set in such a manner that a circuit including the first transmission line, the second transmission line, and the first capacitor resonates in series at a predetermined fundamental frequency, a circuit including the first transmission line, the first capacitor, and the second capacitor resonates in parallel at a third harmonic frequency being a tripled frequency of the fundamental frequency, and a circuit including the second transmission line and the third capacitor resonates in series at the third harmonic frequency.

An acoustic wave filter includes a first signal terminal, an antenna terminal, a ladder-type filter connected between the first signal terminal and the antenna terminal and including one or more serial resonators and one or more parallel resonators connected in a ladder shape, and a capacitor part and an inductor part which are connected in series between the first signal terminal and a reference potential.

A multilayer substrate includes a pair of first capacitor electrodes, a pair of second capacitor electrodes, and a dielectric substrate. Electrodes of the pair of first capacitor electrodes are disposed in dielectric substrate so as to face each other in a thickness direction of the dielectric substrate. Electrodes of the pair of second capacitor electrodes are disposed in the dielectric substrate so as to face each other in the thickness direction. A first element and a second element that are disposed in or on the dielectric substrate, and the pair of second capacitor electrodes, the pair of first capacitor electrodes, and a ground electrode that are disposed in the dielectric substrate are arranged in the stated order in the thickness direction. The pair of second capacitor electrodes at least partially overlaps the pair of first capacitor electrodes when viewed in plan in the thickness direction.

The, present application provides a filtering circuit and a. TV antenna amplifier, the filtering circuit includes a switching module, and the switching module includes a control unit and at least two filtering units. The present application switchably render one of the at least two filtering units conductive through the control unit, and filter the signals of different frequencies in the input signals through the at least two filtering units, so that different filtering units can be switched according to the filtering requirements of the frequency signal in different regions, which makes it a wide application range.

An LC composite component includes a magnetic substrate with magnetism, a magnetic layer with magnetism, inductors, capacitors, and core parts with magnetism. The magnetic substrate includes a first surface and a second surface on a side opposite to the first surface. The magnetic layer is disposed to face the first surface of the magnetic substrate. The inductors and the capacitors are disposed between the first surface of the magnetic substrate and the magnetic layer. The core parts are disposed between the first surface of the magnetic substrate and the magnetic layer and connected to the magnetic layer. The thickness of the core part is 1.0 or more times the thickness of the magnetic layer, the thickness of the magnetic substrate is 1.0 or more times the thickness of the magnetic layer.

A high-power, frequency-tunable, harmonic filtering system for multiple operating frequencies includes a first SPMT switch circuitry, a second SPMT switch circuitry, and high-power, frequency-tunable harmonic filters (HFHFs). The first SPMT single-pole terminal is configured to receive a high-power RF input signal. The second SPMT single-pole terminal is configured to output a high-power RF output signal. Each of the HFHFs is connected to a respective one of the first SPMT multi-throw terminals and a respective one of the second SPMT multi-throw terminals. Each of the HFHFs is interposed between the respective first and second multi-throw terminals along a respective RF signal pathway between them. Each operating frequency is associated with one of the HFHFs. The respective operating frequency is associated with one of multiple cutoff frequencies of the respective HFHF. A frequency response of each of the HFHF is tunable to multiple cutoff frequencies in accordance with selection of respective shunt capacitances selectable under control of a controller.

A matching network is a matching network of a power amplifier circuit that outputs a signal obtained by a differential amplifier amplifying power of a high-frequency signal. The matching network includes an input-side winding connected between differential outputs of the differential amplifier; an output-side winding that is coupled to the input-side winding via an electromagnetic field and whose one end is connected to a reference potential; a first LC series resonant circuit including a capacitive element and an inductive element connected in series with each other, and being connected in parallel with the input-side winding; and a second LC series resonant circuit including a capacitive element and an inductive element connected in series with each other, and being connected in parallel with the output-side winding.

According to various embodiments, an example wireless power transmitter may include a transistor configured to output an amplified signal based on an input signal and a driving voltage, a first capacitor coupled to the transistor in parallel, a first LC resonant circuit coupled to the transistor in parallel and including a first inductor and a second capacitor coupled to the first inductor in series, a third capacitor having a first end coupled to an output terminal of the transistor and the first LC resonant circuit, a feeding coil coupled to a second end of the third capacitor in series, and having at least a part configured to form a second LC resonant circuit with the third capacitor, and a transmission resonator including a transmission coil and a fourth capacitor coupled to the transmission coil in series. At least a part of the transmission coil may be magnetically coupled with the feeding coil, and at least a part of power received from the feeding coil may be output to an outside through the transmission resonator.