A method of constructing an RF filter comprises designing an RF filter that includes a plurality of resonant elements disposed, a plurality of non-resonant elements coupling the resonant elements together to form a stop band having a plurality of transmission zeroes corresponding to respective frequencies of the resonant elements, and a sub-band between the transmission zeroes. The non-resonant elements comprise a variable non-resonant element for selectively introducing a reflection zero within the stop band to create a pass band in the sub-band. The method further comprises changing the order in which the resonant elements are disposed along the signal transmission path to create a plurality of filter solutions, computing a performance parameter for each of the filter solutions, comparing the performance parameters to each other, selecting one of the filter solutions based on the comparison of the computed performance parameters, and constructing the RF filter using the selected filter solution.

A thin-film filter may include a monolithic substrate and a patterned conductive layer formed over the monolithic substrate. The patterned conductive layer may include at least one thin-film inductor. The thin-film filter may have a power capacity that is greater than about 25 W. In some embodiments, the thin-film inductor(s) may be connected between the input port and the output port. A heat sink terminal may be exposed along the bottom surface of thin-film filter. In some embodiments, the heat sink terminal may have an exposed heat sink area, and the bottom surface of the thin-film filter has an area that is less than 20 times larger than the exposed heat sink area.

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.

Radio frequency (RF) systems with tunable filters are provided herein. In certain embodiments, an RF system includes a first RF processing circuit configured to process a first frequency band of a first communication standard and a second frequency band of a second communication standard. The first frequency band and the second frequency band are close in frequency and/or partially overlapping in frequency. The first RF processing circuit includes a tunable filter for changing the bandwidth of the first RF processing circuit to enhance the robustness of the first RF processing circuit to blocker or jammer signals of a third frequency band.

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.

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.

An LC filter includes a multilayer body, plate electrodes, capacitor electrodes, and inductor vias. The capacitor electrodes each define a capacitor between the plate electrode and a corresponding one of the capacitor electrodes. A first inductor via is connected between a first capacitor electrode and a first plate electrode. A second inductor via is connected between a second capacitor electrode and the first plate electrode. A third inductor via is connected between a third capacitor electrode and the first plate electrode. A fourth capacitor electrode faces the first and second capacitor electrodes. A fifth capacitor electrode faces the second and third capacitor electrodes. A sixth capacitor electrode faces the first and third capacitor electrodes.

A filter circuit including a plurality of capacitances and a plurality of inductances including one variable reactance that is either an inductance or a capacitance. The filter circuit has a plurality of resonant modes that each correspond to resonance at a resonant frequency between the variable reactance and one or more of the plurality of inductances and one or more of the plurality of capacitances. The variable reactance is conductively coupled with one or more other inductances and capacitances of the pluralities of inductances and capacitances such that a change in the variable reactance causes a change in a resonant frequency of more than one of the plurality of resonant modes. Front-end modules and wireless communication devices incorporating such a filter circuit and a method using such a filter circuit are also described.

The integrated circuit includes a power amplifier, an antenna, and a matching and filtering network including a direct current power supply stage on an output node of the power amplifier, a first section, and a second section. The direct current power supply stage and the two sections include inductor-capacitor “LC” arrangements configured to have an impedance that is matched to the output of the power amplifier in the fundamental frequency band. The LC arrangements of the direct current power supply stage and of the first section are furthermore configured to have resonant frequencies that are respectively adapted to attenuate harmonic frequency bands of the fundamental frequency band.

An electronic component includes a stack and an inductor wound about an axis orthogonal to a stacking direction. The inductor includes a first conductor layer portion and two through hole columns. The first conductor layer portion includes two conductor layers disposed at positions different from each other in the stacking direction and connected in parallel to each other. Area of a first conductor layer is larger than area of a second conductor layer.