A filter circuit includes a first inductor circuit connected in series with a second inductor circuit, and a first capacitor circuit connected in series with a second capacitor circuit. The first inductor circuit and the second inductor circuit are connected between a first input/output port and a second input/output port of the filter circuit. A third inductor circuit is connected between a reference node and a first node that is between the first inductor circuit and the second inductor circuit. A resonator circuit is connected to a second node between the first capacitor circuit and the second capacitor circuit. A fourth inductor circuit is connected between the resonator circuit and the reference node. In some embodiments, another resonator circuit is connected between the input port and the output port of the filter circuit.

In a resonant device, a third plane electrode is located between a first plane electrode and a second plane electrode. A first via electrode connects the first plane electrode and the third plane electrode. A second via electrode, a third via electrode, and a fourth via electrode connect the first plane electrode and the second plane electrode. When the third plane electrode is seen in plan view in a normal direction of the first plane electrode, the third plane electrode includes a first projecting portion overlapping with a first area between the second via electrode and the third via electrode, and a second projecting portion overlapping with a second area between the third via electrode and the fourth via electrode.

Certain aspects of the present disclosure provide a filter circuit and techniques for filtering using the filter circuit. The filter circuit generally includes a first filter stage having a first acoustic wave resonator coupled in a series path between a first port of the filter circuit and a second port of the filter circuit, a first inductor-capacitor (LC) tank circuit, a first capacitor coupled between a first terminal of the first acoustic wave resonator and the first LC tank circuit, the first LC tank circuit being coupled between the first capacitor and a reference potential node, and a second capacitor coupled between a second terminal of the first acoustic wave resonator and the first LC tank circuit. In some aspects, the filter circuit includes one or more other filter stages coupled to the first filter stage.

An electronic component a multilayer body including insulation layers stacked in a stacking direction, a mounting surface that opposes a circuit board when the electronic component is mounted on the circuit board, first and second input/output terminals provided on the mounting surface and adjacent to each other, a ground terminal, a first filter circuit, in the multilayer body, electrically connected between the first input/output terminal and the second input/output terminal, and a ground conductor layer, provided between the first filter circuit and the mounting surface in the stacking direction, that overlaps with the first input/output terminal and the second input/output terminal when viewed in plan view from the stacking direction, and that is connected to the ground terminal.

The present disclosure provides circuits and methods for fabricating circuits. A circuit may include an insulator having a first surface, a second surface, a periphery, a first subset of circuit elements disposed on the first surface, a second subset of circuit elements disposed on the second surface, and at least one conductive sidewall disposed on the periphery, wherein the conductive sidewall electrically couples the first subset of circuit elements to the second subset of circuit elements.

The present disclosure provides a variable filter circuit capable of controlling a band width and a center frequency of a pass band, and also capable of suppressing the total number of pieces of variable reactance. That is, a variable filter circuit includes a serial arm in which a plurality of circuit elements are connected in series with respect to a signal path and a parallel arm in which a plurality of circuit elements are connected in parallel with respect to the signal path, wherein the serial arm and the parallel arm each includes a variable reactance element, a series reactance element that is connected in series to the variable reactance element and resonates therewith, and a parallel reactance element that is connected in parallel to the variable reactance element and resonates therewith.

A circuit and method for providing high-voltage radio-frequency (RF) energy to an instrument at multiple frequencies includes a plurality of inputs each configured to receive an RF voltage signal oscillating at a corresponding frequency, and a step-up circuit for generating magnified RF voltage signals based on the received RF voltage signals. The step-up circuit includes an LC network operable to isolate the RF voltage signals at the plurality inputs from one another while preserving a voltage magnification from each input to a common output at each of the corresponding frequencies.

A resonant element includes first, second, and third plane electrodes, a first via electrode defining a first inductor, a second inductor, and a third inductor. The first via electrode connects the first plane electrode and the second plane electrode, and each of the second inductor and the third inductor connects the first plane electrode and the third plane electrode. The third plane electrode defines a first capacitor together with the second plane electrode, the second inductor includes second via electrodes, and the third inductor includes third via electrodes. Each of the second via electrodes and the third via electrodes is a columnar conductor extending in the extending direction of the first via electrode.

A low pass filter includes a first terminal pair, a second terminal pair, a first coil connected in series between the first terminal pair and the second terminal pair and including a first coil conductor wound around a winding axis, and a second coil connected in parallel between the first terminal pair and the second terminal pair, including a second coil conductor wound around the winding axis, magnetically coupled to the first coil. An area of the first coil conductor is larger than an area of the second coil conductor.

A power dividing circuit includes an input port, a first microstrip line, a first transmission subcircuit, a second transmission subcircuit, and a matching element. The first transmission subcircuit is coupled to a first microstrip line first end, and the first transmission subcircuit includes a first output port and a first resonance unit. The second transmission subcircuit is coupled to a first microstrip line second end, and the second transmission subcircuit includes a second output port and a second resonance unit. The matching element is coupled between the first output port and the second output port, the matching element matches impedances between the first transmission subcircuit and the second transmission subcircuit. A power divider is also provided.