Abstract: Aspects of this disclosure relate to a radio frequency filter with two pass bands. The RF filter employs a first RF bandpass filter coupled to a common RF input and a common RF output. The RF filter further employs a second RF bandpass filter coupled to the common RF input and the common RF output. A first RF pass band of the first RF bandpass filter and a second RF pass band of the RF second bandpass filter are overlapping RF pass bands. Related methods and wireless communication devices are also disclosed.

Abstract: Aspects of this disclosure relate to an acoustic wave filter that includes acoustic wave resonators arranged to filter a radio frequency signal. The acoustic wave resonators include a first acoustic wave resonator. The acoustic wave filter includes a circuit element in parallel with the first acoustic wave resonator in a stage of the acoustic wave filter. The circuit element and the first acoustic wave resonator have different resonant frequencies. The circuit element can reduce an impact of bulk mode of the first acoustic wave resonator on insertion loss of the acoustic wave filter. The first acoustic wave resonator can be a surface acoustic wave resonator in certain embodiments. The circuit element can be a second acoustic wave resonator or a capacitor, for example.

Abstract: Aspects of this disclosure relate to an acoustic wave filter with parallel band pass filters. Each band pass filter can be an acoustic wave filter having a passband. One of the parallel band pass filters can have higher passband frequencies than another of the parallel band pass filters. The passbands of the parallel band pass filters can overlap in an overlap band. One of the parallel band pass filters can have a higher impedance in the overlap band than another of the parallel band pass filters.

Abstract: Aspects of this disclosure relate to a radio frequency system with an antenna, a radio frequency amplifier, and parallel acoustic wave filters. The parallel acoustic wave filters can each be a band pass filter having a passband and resonator area. The passbands of the parallel acoustic filters can be overlap in an overlap band. One of the parallel acoustic wave filters can have a smaller resonator area than another of the parallel acoustic wave filters.

Abstract: Aspects of this disclosure relate to an acoustic wave filter that includes acoustic wave resonators arranged to filter a radio frequency signal. The acoustic wave resonators include a first acoustic wave resonator. The acoustic wave filter includes a circuit element in parallel with the first acoustic wave resonator in a stage of the acoustic wave filter. The circuit element and the first acoustic wave resonator have different resonant frequencies. The circuit element can reduce an impact of bulk mode of the first acoustic wave resonator on insertion loss of the acoustic wave filter. The first acoustic wave resonator can be a surface acoustic wave resonator in certain embodiments. The circuit element can be a second acoustic wave resonator or a capacitor, for example.

Abstract: Aspects of this disclosure relate to an acoustic wave filter that includes acoustic wave resonators arranged to filter a radio frequency signal. The acoustic wave resonators include a first acoustic wave resonator. The acoustic wave filter includes a circuit element in parallel with the first acoustic wave resonator in a stage of the acoustic wave filter. The circuit element and the first acoustic wave resonator have different resonant frequencies. The circuit element can reduce an impact of bulk mode of the first acoustic wave resonator on insertion loss of the acoustic wave filter. The first acoustic wave resonator can be a surface acoustic wave resonator in certain embodiments. The circuit element can be a second acoustic wave resonator or a capacitor, for example.

Abstract: An acoustic wave device is provided with a low-frequency side filter having a low-frequency side passband, a high-frequency side filter having a high-frequency side passband, and first and second balanced terminals. The low-frequency side filter is connected to a first unbalanced terminal. The low-frequency side passband is a frequency band from a first minimum frequency to a first maximum frequency. The high-frequency side filter is connected to a second unbalanced terminal. The high-frequency side passband is a frequency band from a second minimum frequency to a second maximum frequency. The low-frequency side filter includes a first longitudinally-coupled acoustic wave resonator and a first one-terminal pair acoustic wave resonator connected in series to the first longitudinally-coupled acoustic wave resonator. An antiresonant frequency of the first one-terminal pair acoustic wave resonator is set to be higher than the first maximum frequency and lower than the second minimum frequency.

Abstract: An elastic wave filter including a substrate, a signal line disposed on the substrate and connecting a first signal terminal to a second signal terminal, a plurality of series resonators connected to the signal line in series, and a plurality of parallel resonators connected to the signal line. At least one of the series resonator having an anti-resonant frequency closest to the passband of the filter among the plurality of series resonators, and/or the parallel resonator having a resonant frequency closest to the passband of the filter among the plurality of parallel resonators, is covered with a dielectric film that is relatively thicker than a dielectric film covering the other series and/or parallel resonators.

Abstract: An acoustic wave device includes a first longitudinally-coupled acoustic wave filter having interdigital transducer (“IDT”) electrodes arranged in a propagation direction of acoustic wave, and a second longitudinally-coupled acoustic wave filter having IDT electrodes arranged in a propagation direction of acoustic wave. In the IDT electrodes of the first longitudinally-coupled acoustic wave filter, a comb-shaped electrode connected to an input port and another comb-shaped electrode connected to an output port are disposed in an in-phase relation. In the IDT electrodes of the second longitudinally-coupled acoustic wave filter, a comb-shaped electrode connected to an input port and another comb-shaped electrode connected to an output port are disposed in an anti-phase relation. This acoustic wave device has an excellent attenuation characteristic while maintaining a preferable insertion loss.

Abstract: An acoustic wave device includes a first longitudinally-coupled acoustic wave filter having interdigital transducer (“IDT”) electrodes arranged in a propagation direction of acoustic wave, and a second longitudinally-coupled acoustic wave filter having IDT electrodes arranged in a propagation direction of acoustic wave. In the IDT electrodes of the first longitudinally-coupled acoustic wave filter, a comb-shaped electrode connected to an input port and another comb-shaped electrode connected to an output port are disposed in an in-phase relation. In the IDT electrodes of the second longitudinally-coupled acoustic wave filter, a comb-shaped electrode connected to an input port and another comb-shaped electrode connected to an output port are disposed in an anti-phase relation. This acoustic wave device has an excellent attenuation characteristic while maintaining a preferable insertion loss.

Abstract: An acoustic wave device includes a first longitudinally-coupled acoustic wave filter having interdigital transducer (“IDT”) electrodes arranged in a propagation direction of acoustic wave, and a second longitudinally-coupled acoustic wave filter having IDT electrodes arranged in a propagation direction of acoustic wave. In the IDT electrodes of the first longitudinally-coupled acoustic wave filter, a comb-shaped electrode connected to an input port and another comb-shaped electrode connected to an output port are disposed in an in-phase relation. In the IDT electrodes of the second longitudinally-coupled acoustic wave filter, a comb-shaped electrode connected to an input port and another comb-shaped electrode connected to an output port are disposed in an anti-phase relation. This acoustic wave device has an excellent attenuation characteristic while maintaining a preferable insertion loss.

Abstract: A reflector of the elastic wave resonator in an elastic wave device has first and second regions. The second region has third and fourth regions. The first region is located near to the IDTs of the reflector, while the second region is located farther from them. The third region is located nearer to the IDTs in the second region, while the fourth region is located farther from them. As a result that the center frequency of the reflection band in the fourth region is lower than that in the third region, an elastic wave device with low energy loss and insertion loss is provided.

Abstract: An elastic wave device includes a piezoelectric substrate, a pair of reflectors disposed on the piezoelectric substrate along the propagation direction of an elastic wave, and first to fifth comb electrode pairs disposed in this order between the pair of reflectors. Ground comb electrodes of adjacent comb electrode pairs are connected by an even number of connection electrode fingers or by an odd number of connection electrode fingers.

Abstract: An elastic wave filter including a substrate, a signal line disposed on the substrate and connecting a first signal terminal to a second signal terminal, a plurality of series resonators connected to the signal line in series, and a plurality of parallel resonators connected to the signal line. At least one of the series resonator having an anti-resonant frequency closest to the passband of the filter among the plurality of series resonators, and/or the parallel resonator having a resonant frequency closest to the passband of the filter among the plurality of parallel resonators, is covered with a dielectric film that is relatively thicker than a dielectric film covering the other series and/or parallel resonators.

Abstract: An acoustic wave device is provided with a low-frequency side filter having a low-frequency side passband, a high-frequency side filter having a high-frequency side passband, and first and second balanced terminals. The low-frequency side filter is connected to a first unbalanced terminal. The low-frequency side passband is a frequency band from a first minimum frequency to a first maximum frequency. The high-frequency side filter is connected to a second unbalanced terminal. The high-frequency side passband is a frequency band from a second minimum frequency to a second maximum frequency. The low-frequency side filter includes a first longitudinally-coupled acoustic wave resonator and a first one-terminal pair acoustic wave resonator connected in series to the first longitudinally-coupled acoustic wave resonator. An antiresonant frequency of the first one-terminal pair acoustic wave resonator is set to be higher than the first maximum frequency and lower than the second minimum frequency.

Abstract: An elastic wave device includes a first unbalanced terminal, a second unbalanced terminal, a first balanced terminal, a second balanced terminal, a first filter part, and a second filter part. A phase of an electric signal transmitted from first unbalanced terminal to the first balanced terminal in the first filter part is different from a phase of an electric signal transmitted from the second unbalanced terminal to the first balanced terminal in the second filter part. A phase of an electric signal transmitted from the first unbalanced terminal to the second balanced terminal in the first filter part is different from a phase of an electric signal transmitted from the second unbalanced terminal to the second balanced terminal in the second filter part.

Abstract: An acoustic wave device is provided with a low-frequency side filter having a low-frequency side passband, a high-frequency side filter having a high-frequency side passband, and first and second balanced terminals. The low-frequency side filter is connected to a first unbalanced terminal. The low-frequency side passband is a frequency band from a first minimum frequency to a first maximum frequency. The high-frequency side filter is connected to a second unbalanced terminal. The high-frequency side passband is a frequency band from a second minimum frequency to a second maximum frequency. The low-frequency side filter includes a first longitudinally-coupled acoustic wave resonator and a first one-terminal pair acoustic wave resonator connected in series to the first longitudinally-coupled acoustic wave resonator. An antiresonant frequency of the first one-terminal pair acoustic wave resonator is set to be higher than the first maximum frequency and lower than the second minimum frequency.

Abstract: An acoustic wave device includes a first longitudinally-coupled acoustic wave filter having interdigital transducer (“IDT”) electrodes arranged in a propagation direction of acoustic wave, and a second longitudinally-coupled acoustic wave filter having IDT electrodes arranged in a propagation direction of acoustic wave. In the IDT electrodes of the first longitudinally-coupled acoustic wave filter, a comb-shaped electrode connected to an input port and another comb-shaped electrode connected to an output port are disposed in an in-phase relation. In the IDT electrodes of the second longitudinally-coupled acoustic wave filter, a comb-shaped electrode connected to an input port and another comb-shaped electrode connected to an output port are disposed in an anti-phase relation. This acoustic wave device has an excellent attenuation characteristic while maintaining a preferable insertion loss.

Abstract: An elastic wave device includes an elastic wave resonator which includes a comb-shaped electrode pair including a pair of com-shaped electrodes interdigitating with each other and provided on a piezoelectric substrate and which is configured to trap energy of the elastic wave therein. Each of the pair of comb-shaped electrodes includes interdigital electrode fingers connected to a common. A pitch of the interdigital electrode fingers changes along a direction perpendicular to a propagation direction of elastic wave. The elastic wave device has a small insertion loss and operates efficiently.

Abstract: A reflector of the elastic wave resonator in an elastic wave device has first and second regions. The second region has third and fourth regions. The first region is located near to the IDTs of the reflector, while the second region is located farther from them. The third region is located nearer to the IDTs in the second region, while the fourth region is located farther from them. As a result that the center frequency of the reflection band in the fourth region is lower than that in the third region, an elastic wave device with low energy loss and insertion loss is provided.