A bandpass filter is provided that includes series acoustic resonators and shunt acoustic resonators. The shunt acoustic resonators include a first transversely-excited film bulk acoustic resonators (XBAR) that includes a diaphragm comprising a portion of a piezoelectric layer that is over a cavity of the first XBAR and a first interdigital transducer (IDT) on a surface of the piezoelectric layer. The first XBAR is connected between (i) a node directly between a first series acoustic resonator of the plurality of series acoustic resonators and the input port, and (ii) a ground of the bandpass filter. The series and shunt acoustic resonators include one or more solidly-mounted XBARs that includes a portion of a second piezoelectric layer that is solidly mounted over a substrate with a Bragg reflector disposed therebetween.

A coupled resonator filter including a first parallel resonator including a first capacitance connected in parallel with a first inductance. The filter includes a second parallel resonator including a second capacitance connected in parallel with a second inductance and a third parallel resonator including a third capacitance connected in parallel with a third inductance. Magnetic coupling between the first inductance and the second inductance, between the second inductance and the third inductance, and between the first inductance the third inductance occurs in accordance with first, second and third coupling factors, respectively. A frequency response of the coupled resonator filter includes a notch when values of the first coupling factor, the second coupling factor and the third coupling factor satisfy predetermined conditions.

A coupled resonator filter including a first parallel resonator including a first capacitance connected in parallel with a first inductance. The filter includes a second parallel resonator including a second capacitance connected in parallel with a second inductance and a third parallel resonator including a third capacitance connected in parallel with a third inductance. Magnetic coupling between the first inductance and the second inductance, between the second inductance and the third inductance, and between the first inductance the third inductance occurs in accordance with first, second and third coupling factors, respectively. A frequency response of the coupled resonator filter includes a notch when values of the first coupling factor, the second coupling factor and the third coupling factor satisfy predetermined conditions.

A filter device includes an input terminal, an output terminal, and a resonator connected to the input terminal and the output terminal. The resonator includes a first terminal connected to the input terminal, a second terminal connected to the output terminal, first and second inductors, and first to third capacitors. A first end of the first inductor is connected to the first terminal. The second inductor has a first end connected to the second terminal and a second end connected to a second end of the second inductor. A first end of the first capacitor is connected to the first terminal. The second capacitor has a first end connected to the second terminal and a second end connected to the second end of the capacitor. The third capacitor is connected between a second end of the first inductor and a second end of the first capacitor.

A filter circuit, a filter, and an electronic device are disclosed. The filter circuit includes: a first port and a second port arranged opposite to each other, a grounding terminal, a series branch between the first port and the second port, and at least one parallel branch connected with the series branch; where the series branch includes at least one series resonance unit arranged in sequence, each of the at least one parallel branch includes a parallel resonance unit, and the parallel resonance unit is connected with the grounding terminal.

The present disclosure provides a multiplexer and a detector. The multiplexer includes a dielectric base plate, a connection structure, and a plurality of bandpass filters with different operation frequencies. A conductive thin film layer is disposed on a side plane of the dielectric base plate, the conductive thin film layer includes a signal wire and one or more grounding plates on a side of the signal wire. The connection structure is disposed on a side, on which the conductive thin film layer is provided, of the dielectric base plate, and includes a main branch and a plurality of branches, where the main branch is connected to the plurality of branches respectively, and the main branch serves as an input port of the multiplexer. Each of the plurality of bandpass filters with different operation frequencies is disposed on the side, on which the conductive thin film layer is provided, of the dielectric base plate, and is connected to the signal wire and the one or more grounding plates. For each bandpass filter of the plurality of bandpass filters, the bandpass filter includes a first port and a second port, the first port is connected to a corresponding branch of the plurality of branches, and the second port serves as one of a plurality of output ports of the multiplexer.

Techniques for isolation between filters using inductive coupling cancellation are disclosed. An apparatus includes a first filter including a first plurality of inductors and a second filter including a second plurality of inductors. The first and second filters are implemented physically adjacent to one another. First and second ones of the first plurality of inductors and a first one of the second plurality of inductors are polarized in a first direction, while a second one of the second plurality of inductors is polarized in a second direction opposite that of the first direction. The second one of the second plurality of inductors is physically adjacent to one of the first and second ones of the first plurality of inductors such that magnetic coupling currents induced into one another are canceled.

A coupled resonator filter including a first parallel resonator including a first capacitance connected in parallel with a first inductance. The filter includes a second parallel resonator including a second capacitance connected in parallel with a second inductance and a third parallel resonator including a third capacitance connected in parallel with a third inductance. Magnetic coupling between the first inductance and the second inductance, between the second inductance and the third inductance, and between the first inductance the third inductance occurs in accordance with first, second and third coupling factors, respectively. A frequency response of the coupled resonator filter includes a notch when values of the first coupling factor, the second coupling factor and the third coupling factor satisfy predetermined conditions.

Methods, apparatus, systems, and articles of manufacture are described corresponding to current limit circuitry with controlled current variation. An example circuit includes an amplifier having an input terminal and an output terminal; a capacitor having a first terminal and a second terminal, the first terminal of the capacitor coupled to the input terminal of the amplifier, the second terminal of the capacitor coupled to the output terminal of the amplifier; and diode circuitry having a first terminal and a second terminal, the first terminal of the diode circuitry coupled to the first terminal of the capacitor and the input terminal of the amplifier, the second terminal of the diode circuitry coupled to the second terminal of the capacitor and the output terminal of the amplifier.

A filter device includes a first filter including a first inductor, a second filter including a second inductor, a third filter including a third inductor, and a fourth filter including a fourth inductor. The first to fourth inductors are arranged in a manner that an opening of the first inductor and an opening of the third inductor face each other, an opening of the second inductor and an opening of the fourth inductor face each other, the opening of the first inductor and the opening of the second inductor do not face each other, and the opening of the third inductor and the opening of the fourth inductor do not face each other.