ACOUSTIC WAVE FILTER WITH DIFFERENT TYPES OF RESONATORS

Aspects of this disclosure relate to acoustic wave filters that include different types of acoustic wave resonators for series resonators and shunt resonators. In certain embodiments, an acoustic wave filter includes series temperature compensated surface acoustic wave resonators and shunt bulk acoustic wave resonators. Such an acoustic wave filter can be a band pass filter.

BACKGROUND

Technical Field

Embodiments of this disclosure relate to acoustic wave filters.

Description of Related Technology

An acoustic wave filter can include a plurality of resonators arranged to filter a radio frequency signal. Example acoustic wave resonators include surface acoustic wave (SAW) resonators and bulk acoustic wave (BAW) resonators. A surface acoustic wave resonator can include an interdigital transductor electrode on a piezoelectric substrate. The surface acoustic wave resonator can generate a surface acoustic wave on a surface of the piezoelectric layer on which the interdigital transductor electrode is disposed. In BAW resonators, acoustic waves propagate in a bulk of a piezoelectric layer. Example BAW resonators include film bulk acoustic wave resonators (FBARs) and solidly mounted resonators (SMRs).

Acoustic wave filters can be implemented in radio frequency electronic systems. For instance, filters in a radio frequency front end of a mobile phone can include acoustic wave filters. An acoustic wave filter can be a band pass filter. A plurality of acoustic wave filters can be arranged as a multiplexer. For example, three acoustic wave filters can be arranged as a triplexer. As another example, four acoustic wave filters can be arranged as a quadplexer.

Acoustic wave filters with low insertion loss are generally desirable. However, meeting insertion loss specifications for an entire passband of an acoustic wave filter can be challenging.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

One aspect of this disclosure is an acoustic wave filter that includes a plurality of series resonators and a plurality of shunt resonators. The plurality of series resonators including temperature compensated surface acoustic wave resonators. The plurality of shunt resonators including bulk acoustic wave resonators. The plurality of series resonators and the plurality of shunt resonators are together arranged to filter a radio frequency signal. The acoustic wave filter is a band pass filter.

The plurality of series resonators and the plurality of shunt resonators can be co-packaged. The plurality of series resonators can be on a first die and the plurality of shunt resonators can be on a second die. The second die can be stacked with and attached to the first die. The temperature compensated surface acoustic wave resonators can include respective interdigital transducer electrodes on a side of the first die that is facing a side of the second die on which electrodes of respective bulk acoustic wave resonators are located. An inductor can be co-packaged with the plurality of series resonators and the plurality of shunt resonators. A trap circuit can be co-packaged with the plurality of series resonators and the plurality of shunt resonators. A phase shift circuit can be co-packaged with the plurality of series resonators and the plurality of shunt resonators.

The plurality of series resonators can include a Lamb wave resonator. The plurality of shunt resonators can include a Lamb wave resonator.

The bulk acoustic wave resonators can include a film bulk acoustic wave resonator.

The plurality of shunt resonators and the plurality of series resonators can be arranged in a ladder topology.

The acoustic wave filter can include a multi-mode surface acoustic wave filter coupled in series with the plurality of series resonators.

The plurality of series resonators can include a series bulk acoustic wave resonator, and the temperature compensated surface acoustic wave resonators can be coupled to an input/output port of the acoustic wave filter by way of the series bulk acoustic wave resonator.

The acoustic wave filter can be arranged to support dual connectivity. The acoustic wave filter can have a pass band that includes two operating bands. The acoustic wave filter can be a receive filter. The acoustic wave filter can have a pass band that spans an operating band of a first radio access technology and an operating band of a second radio access technology, in which the first radio access technology is different than the second radio access technology. The acoustic wave filter can have a pass band that spans a Long Term Evolution operating band and a New Radio operating band.

Another aspect of this disclosure is an acoustic wave filter that includes: a plurality of series acoustic wave resonators of a first type; and a plurality of shunt acoustic wave resonators of a second type, the series acoustic wave resonators of the first type having a higher quality factor below respective resonant frequencies than series acoustic resonators of the second type, the shunt acoustic resonators of the second type having a higher quality factor in a frequency range between respective resonant frequencies and respective anti resonant frequencies than shunt acoustic resonators of the first type, and the plurality of series acoustic wave resonators of the first type and the plurality of shunt acoustic wave resonators of the second type together arranged as a band pass filter configured to filter a radio frequency signal.

The plurality of series acoustic resonators of the first type can be temperature compensated surface acoustic wave resonators. The plurality of shunt acoustic resonators of the second type can be bulk acoustic wave resonators.

The plurality of series resonators of the first type can be on a first die and the plurality of shunt resonators of the second type can be on a second die. Electrodes the plurality of series resonators of the first type can be on a side of the first die that is facing a side of the second die on which electrodes of the plurality of shunt resonators of the second type are located.

The acoustic wave filter can be a receive filter with a pass band that spans a first operating band and a second operating band. The first operating band can be associated with a different radio access technology than the second operating band.

Another aspect of this disclosure is an acoustic wave filter that includes a plurality of series resonators including bulk acoustic wave resonators; and a plurality of shunt resonators including temperature compensated surface acoustic wave resonators, the plurality of series resonators and the plurality of shunt resonators together arranged as a band stop filter to filter a radio frequency signal.

The plurality of series resonators and the plurality of shunt resonators can be co-packaged. The plurality of series resonators can be on a first die and the plurality of shunt resonators are on a second die. The second die can be stacked with and attached to the first die. The temperature compensated surface acoustic wave resonators can include respective interdigital transducer electrodes on a side of the second die that is facing a side of the first die on which electrodes of respective bulk acoustic wave resonators are located. An inductor can be co-packaged with the plurality of series resonators and the plurality of shunt resonators. A phase shift circuit can be co-packaged with the plurality of series resonators and the plurality of shunt resonators. The phase shift circuit can include a plurality of interdigital transducer electrodes.

The plurality of series resonators can include a Lamb wave resonator. The plurality of shunt resonators can include a Lamb wave resonator. The bulk acoustic wave resonators can include a film bulk acoustic wave resonator. The plurality of shunt resonators and the plurality of series resonators can be arranged in a ladder topology.

Another aspect of this disclosure is acoustic wave filter that includes: a plurality of series acoustic wave resonators of a first type; and a plurality of shunt acoustic wave resonators of a second type, the series acoustic wave resonators of the first type having a lower resonant frequency than the respective shunt acoustic wave resonators of the second type, the series acoustic resonators of the first type having an anti-resonant frequency that aligns with the resonant frequency of respective shunt acoustic resonators of the second type, and the plurality of series acoustic wave resonators of the second type and the plurality of shunt acoustic wave resonators of the first type together arranged as a band stop filter to filter a radio frequency signal.

Another aspect of this disclosure can include an acoustic wave filter in accordance with any suitable principles and advantages disclosed herein and a radio frequency circuit element coupled to the acoustic wave filter. The acoustic wave filter and the radio frequency circuit element are enclosed within a common module package.

The radio frequency circuit element can be a radio frequency amplifier arranged to amplify a radio frequency signal. The radio frequency circuit element can be a switch configured to selectively couple the acoustic wave filter to an antenna port of the radio frequency module.

Another aspect of this disclosure is a wireless communication device that includes an acoustic wave filter in accordance with any suitable principles and advantages disclosed herein, an antenna operatively coupled to the acoustic wave filter, a radio frequency amplifier operatively coupled to the acoustic wave filter and configured to amplify a radio frequency signal, and a transceiver in communication with the radio frequency amplifier.

The wireless communication device can include a baseband processor in communication with the transceiver.

The wireless communication device can be configured to support dual connectivity. The radio frequency amplifier can be a low noise amplifier, the acoustic wave filter can be a receive filter having a passband that spans a first operating band and a second operating band, and the first operating band can be associated with a different radio access technology than the second operating band.

Another aspect of this disclosure is a method of filtering a radio frequency signal that includes receiving a radio frequency signal at a port of the acoustic wave filter in accordance with any suitable principles and advantages disclosed herein and filtering the radio frequency signal with the acoustic wave filter.

Another aspect of this disclosure is an acoustic filter component that includes a first die and a second die. The first die includes a plurality of surface acoustic wave resonators. The first die includes a side on which an interdigital transducer electrode of a first surface acoustic wave resonator of the surface acoustic wave resonators is positioned. The second die includes a plurality of bulk acoustic wave resonators. The second die includes a side on which an electrode of a first bulk acoustic wave resonator of the bulk acoustic wave resonators is positioned. The side of the second die faces the side of the first die. The first die is stacked with and attached to the second die. The surface acoustic wave resonators are as series resonators of an acoustic wave filter. The bulk acoustic wave resonators are as shunt resonators of the acoustic wave filter.

The acoustic filter component can include sidewalls positioned between the first die and the second die. The sidewalls can be included in a packaging structure that encloses the surface acoustic wave resonators and the bulk acoustic wave resonators in a sealed volume. The first die can be attached to the second die via the sidewalls.

The acoustic filter component can include a tuning inductor on the side of the first die. The acoustic filter component of can include a phase shift circuit co-packaged with the surface acoustic wave resonators and the bulk acoustic wave resonators. The acoustic filter component can include a passive impedance element co-packaged with the surface acoustic wave resonators and the bulk acoustic wave resonators. The passive impedance element can be included in a tuning network coupled to the acoustic wave filter.

The surface acoustic wave resonators can be temperature compensated surface acoustic wave resonators.

The first die can include a second plurality of surface acoustic wave resonators of a second acoustic wave filter, the second die can include a second plurality of bulk acoustic wave resonators of the second acoustic wave filter, and the acoustic wave filter and the second acoustic wave filter can be are included in a multiplexer.

The acoustic wave filter can be a band pass filter.

The acoustic wave filter can be a receive filter having a pass band that spans a first operating band and a second operating band. The first operating band and the second operating band can be associated with different radio access technologies.

Another aspect of this disclosure is an acoustic filter component that includes: a first die including a plurality of surface acoustic wave resonators, the first die including a side on which an interdigital transducer electrode of a first surface acoustic wave resonator of the surface acoustic wave resonators is positioned; and a second die including a plurality of bulk acoustic wave resonators, the second die including a side on which an electrode of a first bulk acoustic wave resonator of the bulk acoustic wave resonators is positioned, the side of the second die facing the side of the first die, the first die stacked with and attached to the second die, surface acoustic wave resonators being arranged as shunt resonators of an acoustic wave filter, and the bulk acoustic wave resonators being arranged as series resonators of the acoustic wave filter.

The acoustic filter component can include sidewalls positioned between the first die and the second die. The sidewalls can be included in a packaging structure that encloses the surface acoustic wave resonators and the bulk acoustic wave resonators in a sealed volume. The first die can be attached to the second die via the sidewalls.

The acoustic filter component can include a passive impedance element co-packaged with the surface acoustic wave resonators and the bulk acoustic wave resonators. The passive impedance element can be included in a tuning network coupled to the acoustic wave filter.

The surface acoustic wave resonators can be temperature compensated surface acoustic wave resonators.

The acoustic wave filter can be a band stop filter.

Another aspect of this disclosure is a multiplexer that includes a first filter and a second filter coupled to the first filter at a common node. The first filter includes a plurality of series temperature compensated surface acoustic wave resonators and a plurality of shunt bulk acoustic wave resonators together arranged to filter a radio frequency signal. The first filter is a band pass filter.

The series temperature compensated surface acoustic wave resonators can be on a first die and the shunt bulk acoustic wave resonators can be on a second die. The series temperature compensated surface acoustic wave resonators can include respective interdigital transducer electrodes on a side of the first die that is facing a side of the second die on which electrodes of respective shunt bulk acoustic wave resonators are located.

The multiplexer can include an inductor that is co-packaged with the series temperature compensated surface acoustic wave resonators and the shunt bulk acoustic wave resonators. The multiplexer can include a trap circuit that is co-packaged with the series temperature compensated surface acoustic wave resonators and the shunt bulk acoustic wave resonators. The multiplexer can include a phase shift circuit that is co-packaged with the series temperature compensated surface acoustic wave resonators and the shunt bulk acoustic wave resonators. The phase shift circuit can include a plurality of interdigital transducer electrodes.

The multiplexer can include a third filter coupled to the common node. The first filter can be a receive filter with a first passband that spans a first receive frequency band and a second receive frequency band, the second filter can be a first transmit filter with a second passband that spans a first transmit band associated with the first receive band, and the third filter can be a second transmit filter with a third passband that spans a second transmit band associated with the second receive band. The multiplexer can support dual connectivity.

The first filter can have a passband that includes two operating bands. The first filter can have a passband that includes two operating bands associated with different radio access technologies. The first filter is arranged can be a receive filter.

The second filter can include series temperature compensated surface acoustic wave resonators and shunt temperature compensated surface acoustic wave resonators.

The first filter further can include a Lamb wave resonator in series with the plurality of the series temperature compensated surface acoustic wave resonators. The first filter can include a shunt Lamb wave resonator.

The shunt bulk acoustic wave resonators can include a film bulk acoustic wave resonator. The shunt bulk acoustic wave resonators and the series temperature compensated surface acoustic wave resonators can be arranged in a ladder topology. The multiplexer can include a multi-mode surface acoustic wave filter coupled in series with the series temperature compensated surface acoustic wave resonators.

The first filter can include a series bulk acoustic wave resonator in series with the series temperature compensated surface acoustic wave resonators. The temperature compensated surface acoustic wave resonators can be coupled to an input/output port of acoustic wave filter by way of the series bulk acoustic wave resonator.

For purposes of summarizing the disclosure, certain aspects, advantages and novel features of the innovations have been described herein. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, the innovations may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

Acoustic filters can implement band pass filters. For example, a band pass filter can be formed from temperature compensated surface acoustic wave (TCSAW) resonators. As another example, a band pass filter can be formed from bulk acoustic wave (BAW) resonators, such as film bulk acoustic wave resonators (FBARs).

In acoustic filter applications, insertion loss improvement is typically desired by customers. Insertion loss improvement can help a receive chain with achieve a desired noise figure. Insertion loss improvement can help with implementing a transmit chain with less power consumption and/or better power handling.

Aspects of this disclosure relate to implementing an acoustic wave filter from more than one type of acoustic resonator. In certain embodiments, an acoustic wave filter can include series TCSAW resonators and shunt BAW resonators. Series TCSAW resonators can achieve higher quality factor (Q) in a frequency range below a resonant frequency (fs), while shunt BAW resonators can achieve a higher Q in a frequency range between fs and an anti-resonant frequency (fp).

Compared to a BAW only acoustic wave filter, an acoustic wave filter with series TCSAW resonators and shunt BAW resonators can achieve better low channel insertion loss. Compared to a TCSAW only acoustic wave filter, an acoustic wave filter with series TCSAW resonators and shunt BAW resonators can achieve better overall insertion loss. Accordingly, an acoustic wave filter with series TCSAW resonators and shunt BAW resonators can achieve desirable insertion loss.

Example TCSAW resonators and BAW resonators will now be discussed.

FIG. 1Ais a cross sectional view of a TCSAW device10. The TCSAW device10can be a TCSAW resonator. As illustrated, the TCSAW device10includes a piezoelectric layer12, an interdigital transducer (IDT) electrode14, and a temperature compensation layer16over the IDT electrode14.

The piezoelectric layer12can be a lithium based piezoelectric layer. For example, the piezoelectric layer12can be a lithium niobate layer. As another example, the piezoelectric layer12can be a lithium tantalate layer.

In the TCSAW device10, the IDT electrode14is over the piezoelectric layer12. As illustrated, the IDT electrode14has a first side in physical contact with the piezoelectric layer12and a second side in physical contact with the temperature compensation layer16. The IDT electrode14can include aluminum (Al), molybdenum (Mo), tungsten (W), gold (Au), silver (Ag), copper (Cu), platinum (Pt), ruthenium (Ru), titanium (Ti), the like, or any suitable combination or alloy thereof. The IDT electrode14can be a multi-layer IDT electrode in some applications.

In the TCSAW device10, the temperature compensation layer16can bring a temperature coefficient of frequency (TCF) of the TCSAW device10closer to zero. The temperature compensation layer16can have a positive TCF. This can compensate for a negative TCF of the piezoelectric layer12. The piezoelectric layer12can be lithium niobate or lithium tantalate, which both have a negative TCF. The temperature compensation layer16can be a dielectric film. The temperature compensation layer16can be a silicon dioxide layer. In some other embodiments, a different temperature compensation layer16can be implemented. Some examples of other temperature compensation layers include a tellurium dioxide (TeO2) layer or a silicon oxyfluoride (SiOF) layer.

FIG. 1Billustrates the IDT electrode14of the TCSAW device10ofFIG. 1Ain plan view. The view of the TCSAW device10inFIG. 1Ais along the dashed line from A to A inFIG. 1B. The temperature compensation layer16is not shown inFIG. 1Bto focus on the IDT electrode14. The IDT electrode14is positioned between a first acoustic reflector17A and a second acoustic reflector17B. The acoustic reflectors17A and17B are separated from the IDT electrode14by respective gaps. The IDT electrode14includes a bus bar18and IDT fingers19extending from the bus bar18. The IDT fingers19have a pitch of λ. The TCSAW device10can include any suitable number of IDT fingers19. The pitch λ of the IDT fingers19corresponds to a resonant frequency of the TCSAW device10.

FIG. 2is a cross sectional view of a bulk acoustic wave (BAW) device20. The BAW device20can be a BAW resonator. The illustrated BAW device20is a film bulk acoustic resonator (FBAR). The BAW device20includes a first electrode21, a second electrode22, a piezoelectric layer23, an air cavity24, and a substrate25. The electrodes21and22are on opposing sides of the piezoelectric substrate23. The piezoelectric layer23can be a thin film. The piezoelectric layer23can be an aluminum nitride layer, for example. In other instances, the piezoelectric layer23can be any other suitable piezoelectric layer. The air cavity24is disposed between the electrode21and the substrate25. The substrate25can be a semiconductor substrate. For example, the substrate25can be a silicon substrate. The substrate25can be any other suitable substrate, such as a quartz substrate, a sapphire substrate, a spinel substrate, a ceramic substrate, a glass substrate, or the like. Although not shown inFIG. 2, the BAW device20can include a raised frame structure and/or a recessed frame structure.

FIG. 3Ais a graph that illustrates a resonant frequency (fs) and an anti-resonant frequency (fp) for a shunt TCSAW resonator and a shunt BAW resonator. The shunt TCSAW resonator is generally similar to the TCSAW device10and the shunt BAW resonator is generally similar to the BAW device20.FIG. 3Aindicates that the shunt TCSAW resonator and the shunt BAW resonator have similar fs and fp.

FIG. 3Bis a graph comparing quality factor of the shunt TCSAW resonator and the shunt BAW resonator corresponding to the graph ofFIG. 3A.FIG. 3Bindicates that the Q of the shunt TCSAW resonator from fs to fp is significantly lower than the Q for the shunt BAW resonator from fs to fp. In a ladder filter, such shunt TCSAW resonators can cause more loss at an upper band edge than such shunt BAW resonators.

FIG. 4Ais a graph that illustrates fs and fp for a series TCSAW resonator and a series BAW resonator. The series TCSAW resonator is generally similar to the TCSAW device10and the series BAW resonator is generally similar to the BAW device20.FIG. 4Aindicates that the series TCSAW resonator and the series BAW resonator have similar fs and fp.

FIG. 4Bis a graph comparing quality factor of the series TCSAW resonator and the series BAW resonator corresponding to the graph ofFIG. 4A. The Q of the series BAW resonator below fs is degraded relative to the Q of the TCSAW resonator below fs. In a ladder filter, such series BAW resonators can cause more loss at a lower band edge than such Series TCSAW resonators.

FIGS. 3A to 4Bindicate that TCSAW resonators can result in more insertion loss at an upper band edge and that BAW resonators can result in more insertion loss at a lower band edge than TCSAW resonators for a band pass filter. Achieving low insertion loss at both the lower band edge and the upper band edge is generally desirable. An acoustic wave filter with series TCSAW resonators and shunt BAW resonators can achieve desirable insertion loss at both the lower band edge and the upper band edge of a passband. Similarly, an acoustic wave filter with series acoustic wave resonators of a first type and shunt acoustic wave resonators of a second type can also achieve such desirable insertion loss when (a) series resonators of the first type have higher Q than series resonators of the second type in a frequency range below fs and (b) shunt resonators of the second type have higher Q than shunt resonators of the first type in a frequency range between fs and fp. These relationships can be for band pass filters.

In certain applications, acoustic resonators can be arranged as a band stop filter. In such applications, the relationship of the series acoustic resonators and shunt acoustic resonators can be reversed relative to a band pass filter. For example, an acoustic wave filter arranged as a band stop filter with shunt TCSAW resonators and series BAW resonators can achieve desirable characteristics in a stop band. The fp of shunt TCSAW resonators can align to (e.g., be equal to or approximately equal to) fs of respective series BAW resonators for a band stop filter. The shunt TCSAW resonators can have higher resonant frequencies than respective series BAW resonators. The following relationship can hold for resonators of a band stop filter: fs_BAW<fp_BAW=fs_TCSAW<fp_TCSAW. Other suitable types of acoustic resonators with similar characteristics and/or satisfying these relationships can alternatively or additionally be used in a band pass filter to achieve desirable characteristics in a stop band of the band stop filter.

FIG. 5is a schematic diagram of a ladder filter50according to an embodiment. The ladder filter50includes shunt BAW resonators52and series TCSAW resonators54coupled between RF input/output ports Port1and Port2. The ladder filter50is an example topology of a band pass filter formed from acoustic resonators. In a band pass filter with a ladder filter topology, the shunt resonators can have lower resonant frequencies than the series resonators. The ladder filter50can be arranged to filter an RF signal. As illustrated, the shunt BAW resonators include resonators R1, R3, R5, R7, and R9. The illustrated series TCSAW resonators54include resonators R2, R4, R6, R8, and R10. The first RF input/output port Port1can be a transmit port for a transmit filter or a receive port for a receive filter. The second RF input/output port Port2can be an antenna port. Any suitable number of series acoustic resonators can be in included in a ladder filter. Any suitable number of shunt acoustic wave resonators can be included in a ladder filter.

FIG. 6Ais a graph comparing insertion loss of the ladder filter ofFIG. 5to an all BAW ladder filter in a passband of the filters. The ladder filter50has a lower insertion loss at a lower band edge compared to the all BAW ladder filter. The low channel insertion loss can improve with series TCSAW resonators due to Q of the series TCSAW resonators being higher below fs than for series BAW resonators.

FIG. 6Bis a graph comparing insertion loss of the ladder filter50ofFIG. 5to an all BAW ladder filter over a wider frequency range than inFIG. 6A.FIG. 6Bindicates that the ladder filter50can achieve insertion loss below a specification outside of the passband.

FIG. 7Ais a graph comparing insertion loss of the ladder filter50ofFIG. 5to an all TCSAW ladder filter in a passband of the filters. The ladder filter50has a lower insertion loss throughout the passband compared to the all TCSAW ladder filter. The insertion loss at an upper band edge is significantly improved for the ladder filter50compared to the all TCSAW ladder filter. The shunt BAW resonators of the ladder filter50can have a higher Q between fs and fp compared to shunt TCSAW resonators of the all TCSAW ladder filter. This higher Q can improve the insertion loss for the ladder filter50.

FIG. 7Bis a graph comparing insertion loss of the ladder filter50ofFIG. 5to an all TCSAW ladder filter over a wider frequency range than inFIG. 7A.FIG. 7Bindicates that the ladder filter50can achieve insertion loss below a specification outside of the passband.

FIG. 8Ais a schematic diagram of a ladder filter80according to another embodiment. The ladder filter80includes a plurality of acoustic resonators R1, R2, . . . , RN-1, and RN arranged between a first input/output port PORT1and a second input/output port PORT1. One of the input/output ports PORT1or PORT2can be an antenna port. In certain instances, the other of the input/output ports PORT1or PORT2can be a receive port. In some other instances, the other of the input/output ports PORT1or PORT2can be a transmit port.

The ladder filter80illustrates that any suable number of ladder stages can be implemented in a ladder filter in accordance with any suitable principles and advantages disclosed herein. Ladder stages can start with a series resonator or a shunt resonator from any input/output port of the ladder filter80as suitable. As illustrated, the first ladder stage from the input/output port PORT1begins with a shunt resonator R1. As also illustrated, the first ladder stage from the input/output port PORT2begins with a series resonator RN.

The ladder filter80includes shunt resonators R1and RN-1 and series resonator R2and RN. The series resonators of the ladder filter80including resonators R2and RN can be acoustic resonators of a first type that have higher Q than series resonators of a second type in a frequency range below fs. The shunt resonators of the ladder filter80including resonators R1and RN-1 can be acoustic resonators of the second type and have higher Q than shunt resonators of the first type in a frequency range between fs and fp. This can lead to a reduced insertion loss. The ladder filter80can be a band pass filter with series resonators of the first type and shunt resonators of the second type. In some other embodiments, the series resonators of the ladder filter80including resonators R2and RN can be acoustic resonators of the second type and the shunt resonators of the ladder filter80including resonators R1and RN-1 can be acoustic resonators of the first type. In such embodiments, the ladder filter80can be a band pass filter.

The resonators of the first type can be TCSAW resonators and the resonators of the second type can be BAW resonators. Accordingly, the ladder filter80can include series TCSAW resonators and shunt BAW resonators in certain embodiments. Such BAW resonators can include FBARs and/or solidly mounted resonators (SMRs).

The resonators of the first type can be multi-layer piezoelectric substrate (MPS) SAW resonators and the resonators of the second type can be BAW resonators. Accordingly, the ladder filter80can include series MPS SAW resonators and shunt BAW resonators. Such BAW resonators can include FBARs and/or SMRs in certain embodiments.

The resonators of the first type can be non-temperature compensated SAW resonators and the resonators of the second type can be BAW resonators. Accordingly, the ladder filter80can include series non-temperature compensated SAW resonators and shunt BAW resonators in certain embodiments. Such BAW resonators can include be FBARs and/or SMRs.

In a band pass filter with a ladder filter topology, such as the acoustic wave filter80, the shunt resonators can have lower resonant frequencies than the series resonators. In certain embodiments, the shunt resonators of the acoustic wave filter80are BAW resonators and the series resonators of the acoustic wave filter80are TCSAW resonators. In such embodiments, the acoustic wave filter80can be a band pass filter. Such a band pass filter can achieve low insertion loss at both a lower band edge and an upper band edge of a passband.

In a band stop filter with a ladder filter topology, such as acoustic wave filter80, the shunt resonators can have higher resonant frequencies than the series resonators. In certain embodiments, the acoustic wave filter80is a band stop filter, the shunt resonators of the acoustic wave filter80are TCSAW resonators and the series resonators of the acoustic wave filter80are BAW resonators. Such a band stop filter can achieve desirable characteristics in a stop band of the band stop filter.

In some applications of an acoustic wave filter that includes TCSAW series resonators and BAW shunt resonators, such as a transmit filter with a relatively high power handling specification, one or more series resonators close to a transmit port (or the lower frequency series resonators) can be BAW resonators to help with ruggedness.

In certain applications, the ladder filter80can be included in a multiplexer in which relatively high gamma for the ladder filter80in one or more higher frequency carrier aggregation bands is desired. In such applications, an acoustic filter can include shunt resonators of the shunt type and an acoustic resonator of the second type can be included as a series resonator by which other series resonators of the first type are coupled to a common port of the multiplexer. This can increase gamma of the ladder filter80in the one or more higher frequency carrier aggregation bands. For example, in applications where the second input/output port PORT2is a common port of a multiplexer, the series resonator RN can be a BAW resonator, other series resonators of the ladder filter80can be TCSAW resonators, and the shunt resonators R1and RN-1 can be BAW resonators. By having the series resonator RN closest to the common node be a BAW resonator instead of a TCSAW resonator, gamma can be increased for the ladder filter80in one or more higher frequency carrier aggregation bands in such applications.

In some applications, the ladder filter80can be a transmit filter. In such applications, an acoustic resonator of the second type can be included as a series resonator by which other series resonators of the first type are coupled to a transmit port of the transmit filter. For example, in applications where the second input/output port PORT2is a transmit port of a transmit filter, the series resonator RN can be a BAW resonator, other series resonators of the ladder filter80can be TCSAW resonators, and the shunt resonators R1and RN-1 can be BAW resonators.

In certain applications, the ladder filter80can include more than two types of acoustic resonators. In such applications, the majority of the series resonators can be acoustic resonators of the first type (e.g., TCSAW resonators) and the majority of shunt resonators can be resonators of the second type (e.g., BAW resonators). The ladder filter80can include a third type of resonator as a shunt resonator and/or as a series resonator in such applications. The third type of resonator can be a Lamb wave resonator, for example. One such example Lamb wave resonator will be discussed with reference toFIG. 8B. The acoustic wave filter80can include a plurality series resonators including temperature compensated surface acoustic wave resonators and a plurality shunt resonators including a Lamb wave resonator arranged as shunt resonator. The acoustic wave filter80can include a plurality series resonators including a Lamb wave resonator and a plurality shunt resonators including bulk acoustic wave resonators arranged as shunt resonators.

FIG. 8Bis a cross sectional diagram of a Lamb wave resonator85. A Lamb wave resonator can implement one or more series resonators and/or one or more shunt resonators in the ladder filter80. The Lamb wave resonator85includes feature of a SAW resonator and an FBAR. As illustrated, the Lamb wave resonator85includes a piezoelectric layer23, an IDT electrode14on the piezoelectric layer23, and an electrode21. The resonant frequency of the Lamb wave resonator85can be based on the thickness of the piezoelectric layer23and/or the geometry of the IDT electrode14. An air cavity24is disposed between the electrode21and a substrate25. Although the Lamb wave resonator85ofFIG. 8Ais a free standing Lamb wave resonator, a solidly mounted resonator (SMR) Lamb wave resonator with a solid acoustic mirror (e.g., acoustic Bragg reflectors) can alternatively or additionally be implemented.

An acoustic wave filter including more than one type of acoustic resonator in accordance with any suitable principles and advantages disclosed herein can be implemented in a variety of different filter topologies. Example filter topologies include without limitation ladder filters, lattice filters, hybrid ladder and lattice filters, filters that include ladder stages and a multi-mode SAW filter, and the like. Some example filter topologies will now be discussed.

FIG. 9is a schematic diagram of a lattice filter90. The lattice filter90is an example topology of a band pass filter formed from acoustic wave resonators. The lattice filter80can be arranged to filter an RF signal. As illustrated, the lattice filter90includes acoustic wave resonators RL1, RL2, RL3, and RL4. The acoustic wave resonators RL1and RL2are series resonators. The acoustic wave resonators RL3and RL4are shunt resonators. The illustrated lattice filter90has a balanced input and a balanced output. The lattice filter90can be implemented with different type of acoustic resonators in accordance with any suitable principles and advantages disclosed herein. For example, the series resonators RL1and RL2can be TCSAW resonators and the shunt resonators RL3and RL4can be BAW resonators for a band pass filter.

FIG. 10is a schematic diagram of a hybrid ladder and lattice filter100. The illustrated hybrid ladder and lattice filter includes series acoustic resonators RL1, RL2, RH3, and RH4and shunt acoustic resonators RL3, RL4, RH1, and RH2. The hybrid ladder and lattice filter100can be implemented with different type of acoustic resonators in accordance with any suitable principles and advantages disclosed herein. For example, the series resonators RL1, RL2, RH3, and RH4can be TCSAW resonators and the shunt resonators RL3, RL4, RH1, and RH2can be BAW resonators for a band pass filter.

FIG. 11is a schematic diagram of an acoustic filter110that includes ladder stages and a multi-mode surface acoustic wave filter112. The illustrated acoustic filter110includes series resonators R2and R4, shunt resonators R1and R3, and multi-mode surface acoustic wave filter112. The filter110can be a receive filter. The multi-mode surface acoustic wave filter112can be connected to a receive port. The multi-mode surface acoustic wave filter112includes longitudinally coupled IDT electrodes. The multi-mode surface acoustic wave filter112can include a temperature compensation layer over longitudinally coupled IDT electrodes in certain applications. The series resonators R2and R4can be TCSAW resonators and the shunt resonators R1and R3can be BAW resonators for a band pass filter. The shunt resonators R1and R3being BAW resonators can help with lower skirt steepness and insertion loss.

Acoustic filters disclosed herein include more than one type of acoustic wave resonator. Such filters can be implemented on a plurality of acoustic filter die. The plurality of acoustic filter die can be stacked and co-packaged with each other in certain applications. Embodiments of packaged components will now be discussed.

FIG. 12is a schematic block diagram of a packaged component120that includes a plurality of acoustic resonator die122and124. The packaged component120includes a first acoustic resonator die122and a second acoustic resonator die124. An acoustic filter can include series acoustic resonators of the first acoustic resonator die122and shunt acoustic resonators of the second acoustic resonator die124. In certain applications, a duplexer or other multiplexer can include series acoustic resonators on the first acoustic resonator die122and shunt acoustic resonators on the second acoustic resonator die124. The first acoustic resonator die122can be a TCSAW die. The second acoustic resonator die124can be a BAW die. The acoustic resonator die122and124can be positioned on a common packaging substrate, such as a laminate substrate. The acoustic resonator die122and the acoustic resonator die124can be stacked with each other in certain applications.

FIG. 13is a cross sectional diagram of a co-packaged stacked die acoustic filter component130according to an embodiment. The co-packaged stacked die acoustic filter component130can implement the ladder filter50ofFIG. 5and/or the ladder filter80ofFIG. 8A. The co-packaged stacked die acoustic filter component130includes a TCSAW die stacked with and attached to a BAW die. The BAW die includes a first substrate131and a BAW resonator134on the first substrate131. The first substrate131can be a silicon substrate, for example. The illustrated BAW resonator134is an FBAR. The illustrated BAW resonator134includes a raised frame structure. The TCSAW die includes a second substrate132and a TCSAW resonator135on the second substrate132. The second substrate132can be a lithium niobate substrate or a lithium tantalate substrate. The BAW resonator134can be a shunt resonator of an acoustic wave filter and the TCSAW resonator135can be a series resonator of the acoustic wave filter. The BAW resonator134can be electrically connected to the TCSAW resonator135within the co-packaged stacked die acoustic filter component130.

Any suitable number of BAW resonators can be included on the first substrate131. For example, additional BAW resonators can be on the first substrate131of the co-packaged stacked die acoustic filter component130can be positioned behind and/or in front of the BAW resonator134. Such BAW resonators can include a plurality of BAW resonators of an acoustic wave filter and/or BAW resonators of two or more acoustic wave filters.

Any suitable number of TCSAW resonators can be included on the second substrate132. For example, additional TCSAW resonators can be on the second substrate132of the co-packaged stacked die acoustic filter component130can be positioned behind and/or in front of the TCSAW resonator135. Such TCSAW resonators can include a plurality of TCSAW resonators of an acoustic wave filter and/or TCSAW resonators of two or more acoustic wave filters.

A Lamb wave element can be included on the second substrate132in some applications. Such a Lamb wave element can be a resonator of an acoustic wave filter that includes the TCSAW resonator135or a delay element in a phase shift circuit. A Lamb wave element can be included on the first substrate131in some applications. Such a Lamb wave element can be a resonator of an acoustic filter that includes the BAW resonator134or a delay element in a phase shift circuit.

Active sides of the substrates131and132face each other. The BAW resonator134includes an electrode on a side of the first substrate131that faces a side of the second substrate132on which the IDT electrode of the TCSAW resonator135is positioned. The BAW resonator134and the TCSAW resonator135are enclosed by the first substrate131, the second substrate132, and sidewalls133. The BAW resonator134and the TCSAW resonator135are hermetically sealed together within a cavity. The sidewalls133are included in a packaging structure that encloses the BAW resonator134and the TCSAW resonator135in a sealed volume. As illustrated, the TCSAW die and the BAW die are attached via the sidewalls133.

One or more other components can be enclosed in the co-packaged stacked die acoustic filter component130together with the BAW resonator134and the TCSAW resonator135. The one or more other components can include passive impedance element(s) of a tuning network, a trap circuit, phase delay elements, the like, or any suitable combination thereof. For example, the illustrated co-packaged stacked die acoustic filter component130includes tuning network including a tuning inductor136. The tuning network can be a matching network. The tuning inductor136can be a matching inductor. The tuning network can be coupled to the acoustic wave filter that includes the series TCSAW resonator135and the shunt BAW resonator134. Example tuning networks will be discussed with reference toFIGS. 14 to 15D. Alternatively or additionally, a phase shift circuit can be implemented using IDTs on the second substrate132to provide cancellation of noise components for the acoustic wave filter. An example of such a phase shift circuit will be discussed with reference toFIG. 16.

The illustrated co-packaged stacked die acoustic filter component130also includes vias137though the first substrate131to provide electrical connections to contacts138of the co-packaged stacked die acoustic filter component130.

FIG. 14is a schematic block diagram of a system140that includes an acoustic wave filter142and a tuning network144. The tuning network144can provide impedance matching, phase rotation, and/or other tuning for the acoustic wave filter142. The acoustic wave filter142can be implemented in accordance with any suitable principles and advantages disclosed herein. One or more components of the tuning network144can be co-packaged with acoustic resonators of the acoustic wave filter142.

FIGS. 15A, 15B, 15C, and 15Dare schematic diagrams of tuning networks. These tuning networks are inductor-capacitor tuning networks that can implement the tuning network144ofFIG. 14. The tuning inductor136ofFIG. 13can implement any of the inductors shown inFIGS. 15A to 15D.FIG. 15Aillustrates a tuning network150that includes a capacitor C1in parallel with an inductor L1.FIG. 15Billustrates a tuning network152that includes a capacitor C1in series with an inductor L2.FIG. 15Cillustrates a tuning network154that includes a parallel capacitor-inductor circuit in series with an inductor L2, in which the parallel capacitor-inductor circuit includes a capacitor C1in parallel with an inductor L1.FIG. 15Cillustrates a tuning network156that includes a parallel capacitor-inductor circuit in series with a capacitor C2, in which the parallel capacitor-inductor circuit includes a capacitor C1in parallel with an inductor L1. Any of the capacitors ofFIGS. 15A to 15Dcan be implemented by an explicit capacitor and/or acoustic resonator arranged as a capacitor.

FIG. 16is a schematic diagram of a multiplexer160with a phase shift circuit166. As illustrated, the multiplexer160includes a first filter162, a second filter164, and a phase shift circuit166. The illustrated multiplexer160is a duplexer. The first filter162and the second filter164are coupled together at a common node, which is an antenna node ANT inFIG. 16.

The first filter162can be a transmit filter and the second filter164can be a receive filter. Alternatively, the first filter162can be a receive filter and the second filter164can be another receive filter. Alternatively, the first filter162can be a transmit filter and the second filter164can be another receive filter.

The first filter162can be implemented in accordance with any suitable principles and advantages disclosed herein. For example, the first filter162can include series TCSAW resonators and shunt BAW resonators. The second filter164can be an acoustic wave filter, an inductor-capacitor filter, or a hybrid acoustic inductor-capacitor filter. In certain instances, the first filter162and the second filter164can each be implemented with at least two types of acoustic resonators in accordance with any suitable principles and advantages disclosed herein.

The phase shift circuit166can generate an anti-phase radio frequency (RF) signal to cancel a target signal at a desired frequency. The phase shift circuit166can improve the isolation and attenuation of RF acoustic wave filters, such as BAW filters (e.g., FBAR filters or SMR filters), SAW filters, and Lamb wave filters in the multiplexer160. The illustrated phase shift circuit166can provide cancelation and/or isolation between a transmit port and a receive port, between two different transmit ports, or between two different receive ports. The phase shift circuit166can be implemented in a co-packaged stacked die acoustic filter component. For example, the phase shift circuit166can include IDTs on the same piezoelectric substrate as TCSAW resonators of the first filter162in a co-packaged stacked die acoustic filter component. The phase shift circuit166can be implemented in accordance with any suitable principles and advantages described in U.S. Pat. No. 9,246,533 and/or U.S. Pat. No. 9,520,857, the disclosures of each of these patents are hereby incorporated by reference in their entireties herein.

FIG. 17Ais a schematic diagram of a multiplexer170according to an embodiment. The multiplexer170can support dual connectivity. In dual connectivity, such as E-UTRAN New Radio-Dual Connectivity (EN-DC), fourth generation (4G) Long Term Evolution (LTE) signals and fifth generation (5G) New Radio (NR) signals can be separately received in a user equipment and the streams can be aggregated. With dual connectivity, the 4G and 5G signals can be received concurrently.

The illustrated multiplexer170is a triplexer. As illustrated, the multiplexer170includes a first transmit filter172coupled between a first transmit node BATx and a common node ANT, a second transmit filter174coupled between a second transmit node BBTx and the common node ANT, and a receive filter176coupled between a receive node BA+BBRx and the common node ANT. The triplexer170also include a first series inductor LS1in series between the first transmit node BATx and the first transmit filter172, a second series inductor LS2in series between the second transmit node BBTx and the second transmit filter174, a third series inductor LS3in series between the receive node BA+BBRx and the receive filter176, and a shunt inductor LA1coupled to the common node ANT. InFIG. 17A, the first transmit filter172, the second transmit filter174, and the receive filter176are coupled to each other at the common node ANT. The common node ANT can be an antenna node.

FIG. 17Bis a diagram illustrating the passbands of filters172,174, and176of the multiplexer170ofFIG. 17A. The filters172,174, and176of the multiplexer170can each be band pass filters. The first transmit filter172can have passband that includes a Band A transmit band. The second transmit filter172can have a passband that includes a Band B transmit band. The receive filter176can have a passband that includes both a Band A receive band and a Band B receive band. This can enable the receive filter176to concurrently receive and filter Band A and Band B receive signals. The Band A receive band can overlap with the Band B receive band in certain applications. The Band A receive band can be non-overlapping with the Band B receive band in some other applications. Band A and Band B can be associated with different radio access technologies. For example, Band A can be a 4G LTE band and Band B can be a 4G NR band.

As shown inFIG. 17B, passband of the receive filter176can have a lower edge that is above the passband of the first transmit filter172and an upper edge that is below the passband of the second transmit filter174. The lower edge of the passband of the receive filter176can be relatively close to an upper edge of the passband of the first transmit filter172. The upper edge of the passband of the receive filter176can be relatively close to a lower edge the passband of the second transmit filter172.

The receive filter176can support a relatively wide passband and/or relatively narrow separation. The relatively wide passband can span at least two receive operating bands. The relatively narrow separation can due to a relatively narrow gap in between the respective transmit and receive operating bands. As one example, the gap between a transmit band and corresponding receive band can be less than 2% (e.g., between 0.5% and 2%) of a frequency halfway between the transmit band and the receive band.

A relatively large coupling factor and a relatively high Q at resonance can be desirable for the receive filter176. This can contribute to the receive filter176achieving a relatively low insertion loss over a relatively wide passband. In the multiplexer170, the receive filter176can include two types of acoustic resonators in accordance with any suitable principles and advantages disclosed herein. For example, the receive filter176can include a plurality of series temperature compensated surface acoustic wave resonators and a plurality of shunt bulk acoustic wave resonators together arranged to filter a radio frequency signal. The transmit filters172and/or174can include any suitable filters, such as one or more acoustic wave filters, one or more acoustic wave filters that include two or more types of acoustic wave resonators (e.g., one or more filters with series TCSAW resonators and shunt BAW resonators), one or more inductor-capacitor filters, or one or more hybrid filters that includes an inductor-capacitor filter and acoustic resonators. As one example, the transmit filters172and174can each be TCSAW filters.

Filters, such as the filter176ofFIG. 17B, that include a pass band that spans operating bands for two different radio access technologies can be implemented in dual connectivity applications. An example dual connectivity network topology will be discussed with reference toFIG. 17C.

With the introduction of the 5G NR air interface standards, the 3rd Generation Partnership Project (3GPP) has allowed for the simultaneous operation of 5G and 4G standards in order to facilitate the transition. This mode can be referred to as Non-Stand-Alone (NSA) operation or E-UTRAN New Radio-Dual Connectivity (EN-DC) and can involve both 4G and 5G carriers being simultaneously transmitted from a user equipment (UE). EN-DC can present technical challenges for measuring power associated with individual transmit paths. Radio frequency systems disclosed herein can measure power associated with a transmit path in dual connectivity applications.

In certain EN-DC applications, dual connectivity NSA involves overlaying 5G systems onto an existing 4G core network. For dual connectivity in such applications, the control and synchronization between the base station and the UE can be performed by the 4G network while the 5G network is a complementary radio access network tethered to the 4G anchor. The 4G anchor can connect to the existing 4G network with the overlay of 5G data/control.

FIG. 17Cis a diagram of an example dual connectivity network topology. This architecture can leverage LTE legacy coverage to ensure continuity of service delivery and the progressive rollout of 5G cells. A UE180can simultaneously receive dual downlink LTE and NR carriers. The UE180can receive a downlink LTE carrier Rx1from an Evolved Node B (eNB)181while receiving a downlink NR carrier Rx2from the gNode B (gNB)182to implement dual connectivity. Any suitable combination of uplink carriers Tx1, Tx2and/or downlink carriers Rx1, Rx2can be concurrently transmitted via wireless links in the example network topology ofFIG. 17C. The eNB181can provide a connection with a core network, such as an Evolved Packet Core (EPC). The gNB182can communicate with the core network via the eNB181. Control plane data can be wirelessly communicated between the UE180and eNB181. The eNB181can also communicate control plane data with the gNB182.

In the example dual connectivity topology ofFIG. 17C, any suitable combinations of standardized bands and radio access technologies (e.g., FDD, TDD, SUL, SDL) can be wirelessly transmitted and received. This can present technical challenges related to having multiple separate radios and bands functioning in the UE180. With a TDD LTE anchor point, network operation may be synchronous, in which case the operating modes can be constrained to Tx1/Tx2and Rx1/Rx2, or asynchronous which can involve Tx1/Tx2, Tx1/Rx2, Rx1/Tx2, or Rx1/Rx2. When the LTE anchor is a frequency division duplex (FDD) carrier, the TDD/FDD inter-band operation can involve simultaneous Tx1/Rx1/Tx2and Tx1/Rx1/Rx2.

FIGS. 18A, 18B, 18C, 18D, and 18Eare graphs of simulations of the multiplexer170ofFIG. 17A.FIG. 18Ais a graph that includes a curve for a passband for the first transmit filter172with the scale on the right side in decibels (dB) and noise in the passband with the scale on the left side in dB.FIG. 18Bis a graph that includes a curve for a passband for the receive filter176with the scale on the right side in decibels and noise in the passband with the scale on the left side in dB.FIG. 18Cis a graph that includes a curve for a passband for the second transmit filter174with the scale on the right side in dB and noise in the passband with the scale on the left side in dB.

FIG. 18Dzooms in on insertion loss for the receive passband from the graph ofFIG. 18B.FIG. 18Dis a graph of the passband for the receive filter176of the176with curves for (a) series TCSAW resonators and shunt BAW resonators, (b) all TCSAW resonators, and (c) all BAW resonators.FIG. 18Eis similar to the graph ofFIG. 18Dbut assumes perfect matching. These graphs indicate that that the receive filter176having series TCSAW resonators and shunt BAW resonators can improve insertion loss in the passband of the receive filter176by 0.3 dB to 0.5 dB relative to the other receive filters simulated.

FIG. 19Ais a schematic diagram of a duplexer190that includes an acoustic wave filter according to an embodiment. The duplexer190includes a first filter192and a second filter194coupled to together at a common node COM. One of the filters of the duplexer190can be a transmit filter and the other of the filters of the duplexer190can be a receive filter. The transmit filter and/or the receive filter can be respective ladder filters with acoustic wave resonators having a topology similar to the ladder filter50ofFIG. 5and the ladder filter80ofFIG. 8A. In some other instances, such as in a diversity receive application, the duplexer190can include two receive filters. The common node COM can be an antenna node.

The first filter192is an acoustic wave filter arranged to filter a radio frequency signal. The first filter192can include acoustic wave resonators coupled between a first radio frequency node RF1and the common node. The first radio frequency node RF1can be a transmit node or a receive node. The first filter192includes two types of acoustic resonators in accordance with any suitable principles and advantages disclosed herein.

The second filter194can be any suitable filter arranged to filter a second radio frequency signal. The second filter194can be, for example, an acoustic wave filter, an acoustic wave filter that includes two types of acoustic resonators, an LC filter, a hybrid acoustic wave LC filter, or the like. The second filter194is coupled between a second radio frequency node RF2and the common node. The second radio frequency node RF2can be a transmit node or a receive node

Although example embodiments may be discussed with filters or duplexers for illustrative purposes, any suitable the principles and advantages disclosed herein can be implemented in a multiplexer that includes a plurality of filters coupled together at a common node. Examples of multiplexers include but are not limited to a duplexer with two filters coupled together at a common node, a triplexer with three filters coupled together at a common node, a quadplexer with four filters coupled together at a common node, a hexaplexer with six filters coupled together at a common node, an octoplexer with eight filters coupled together at a common node, or the like. One or more filters of a multiplexer can include an acoustic wave filter including two types of acoustic resonators in accordance with any suitable principles and advantages disclosed herein.

FIG. 19Bis a schematic diagram of a multiplexer195that includes an acoustic wave filter according to an embodiment. The multiplexer195includes a plurality of filters192to196coupled together at a common node COM. The plurality of filters can include any suitable number of filters including, for example, 3 filters, 4 filters, 5 filters, 6 filters, 7 filters, 8 filters, or more filters. Some or all of the plurality of acoustic wave filters can be acoustic wave filters.

The first filter192is an acoustic wave filter arranged to filter a radio frequency signal. The first filter192can include acoustic wave resonators coupled between a first radio frequency node RF1and the common node. The first radio frequency node RF1can be a transmit node or a receive node. The first filter192includes two types of acoustic resonators in accordance with any suitable principles and advantages disclosed herein. The other filter(s) of the multiplexer195can include one or more acoustic wave filters, one or more acoustic wave filters that include two types of acoustic resonators in accordance with any suitable principles and advantages disclosed herein, one or more LC filters, one or more hybrid acoustic wave LC filters, or any suitable combination thereof.

The acoustic wave filters disclosed herein can be implemented in a variety of packaged modules. Some example packaged modules will now be disclosed in which any suitable principles and advantages of the acoustic wave filters and/or acoustic wave resonators disclosed herein can be implemented. The example packaged modules can include a package that encloses the illustrated circuit elements. A module that includes a radio frequency component can be referred to as a radio frequency module. The illustrated circuit elements can be disposed on a common packaging substrate. The packaging substrate can be a laminate substrate, for example.FIGS. 20 to 24are schematic block diagrams of illustrative packaged modules according to certain embodiments. Any suitable combination of features of these packaged modules can be implemented with each other. While duplexers are illustrated in the example packaged modules ofFIGS. 21, 22, and 24, any other suitable multiplexer that includes a plurality of filters coupled to a common node and/or standalone filter can be implemented instead of one or more duplexers. For example, a triplexer can be implemented in certain applications. As another example, one or more filters of a packaged module can be arranged as a transmit filter or a receive filter that is not included in a multiplexer.

FIG. 20is a schematic diagram of a radio frequency module200that includes an acoustic wave component202according to an embodiment. The illustrated radio frequency module200includes the acoustic wave component202and other circuitry203. The acoustic wave component202can include one or more acoustic wave filters in accordance with any suitable combination of features of the acoustic wave filters disclosed herein. The acoustic wave component202can include an acoustic wave filter with series TCSAW resonators and shunt BAW resonators, for example.

The acoustic wave component202shown inFIG. 20includes one or more acoustic wave filters204and terminals205A and205B. The one or more acoustic wave filters204includes an acoustic wave filter implemented in accordance with any suitable principles and advantages disclosed herein. The terminals205A and204B can serve, for example, as an input contact and an output contact. Although two terminals are illustrated, any suitable number of terminals can be implemented for a particular application. The acoustic wave component202and the other circuitry203are on a common packaging substrate206inFIG. 20. The package substrate206can be a laminate substrate. The terminals205A and205B can be electrically connected to contacts207A and207B, respectively, on the packaging substrate206by way of electrical connectors208A and208B, respectively. The electrical connectors208A and208B can be bumps or wire bonds, for example.

The other circuitry203can include any suitable additional circuitry. For example, the other circuitry can include one or more radio frequency amplifiers (e.g., one or more power amplifiers and/or one or more low noise amplifiers), one or more radio frequency switches, one or more additional filters, one or more RF couplers, one or more delay lines, one or more phase shifters, the like, or any suitable combination thereof. The other circuitry203can be electrically connected to the one or more acoustic wave filters204. The radio frequency module200can include one or more packaging structures to, for example, provide protection and/or facilitate easier handling of the radio frequency module200. Such a packaging structure can include an overmold structure formed over the packaging substrate206. The overmold structure can encapsulate some or all of the components of the radio frequency module200.

FIG. 21is a schematic block diagram of a module210that includes duplexers211A to211N and an antenna switch212. One or more filters of the duplexers211A to211N can include an acoustic wave filter in accordance with any suitable principles and advantages disclosed herein. Any suitable number of duplexers211A to211N can be implemented. The antenna switch212can have a number of throws corresponding to the number of duplexers211A to211N. The antenna switch212can include one or more additional throws coupled to one or more filters external to the module210and/or coupled to other circuitry. The antenna switch212can electrically couple a selected duplexer to an antenna port of the module210.

FIG. 22is a schematic block diagram of a module220that includes a power amplifier222, a radio frequency switch224, and duplexers211A to211N according to an embodiment. The power amplifier222can amplify a radio frequency signal. The radio frequency switch224can be a multi-throw radio frequency switch. The radio frequency switch224can electrically couple an output of the power amplifier222to a selected transmit filter of the duplexers211A to211N. One or more filters of the duplexers211A to211N can be an acoustic wave filter in accordance with any suitable principles and advantages disclosed herein. Any suitable number of duplexers211A to211N can be implemented.

FIG. 23is a schematic block diagram of a module230that includes filters232A to232N, a radio frequency switch234, and a low noise amplifier236according to an embodiment. One or more filters of the filters232A to232N can include any suitable number of acoustic wave filters in accordance with any suitable principles and advantages disclosed herein. Any suitable number of filters232A to232N can be implemented. The illustrated filters232A to232N are receive filters. In some embodiments (not illustrated), one or more of the filters232A to232N can be included in a multiplexer that also includes a transmit filter. The radio frequency switch234can be a multi-throw radio frequency switch. The radio frequency switch234can electrically couple an output of a selected filter of filters232A to232N to the low noise amplifier236. In some embodiments (not illustrated), a plurality of low noise amplifiers can be implemented. The module230can include diversity receive features in certain applications.

FIG. 24is a schematic diagram of a radio frequency module240that includes an acoustic wave filter according to an embodiment. As illustrated, the radio frequency module240includes duplexers211A to211N, a power amplifier222, a select switch224, and an antenna switch212. The radio frequency module240can include a package that encloses the illustrated elements. The illustrated elements can be disposed on a common packaging substrate247. The packaging substrate247can be a laminate substrate, for example. A radio frequency module that includes a power amplifier can be referred to as a power amplifier module. A radio frequency module can include a subset of the elements illustrated inFIG. 24and/or additional elements. The radio frequency module240may include any one of the acoustic wave filters in accordance with any suitable principles and advantages disclosed herein.

The duplexers211A to211N can each include two acoustic wave filters coupled to a common node. For example, the two acoustic wave filters can be a transmit filter and a receive filter. As illustrated, the transmit filter and the receive filter can each be a band pass filter arranged to filter a radio frequency signal. One or more of the transmit filters can include an acoustic wave filter in accordance with any suitable principles and advantages disclosed herein. Similarly, one or more of the receive filters can include an acoustic wave filter in accordance with any suitable principles and advantages disclosed herein. AlthoughFIG. 24illustrates duplexers, any suitable principles and advantages disclosed herein can be implemented in other multiplexers (e.g., quadplexers, hexaplexers, octoplexers, etc.) and/or in switch-plexers and/or with standalone filters.

The power amplifier222can amplify a radio frequency signal. The illustrated switch224is a multi-throw radio frequency switch. The switch224can electrically couple an output of the power amplifier222to a selected transmit filter of the transmit filters of the duplexers211A to211N. In some instances, the switch224can electrically connect the output of the power amplifier222to more than one of the transmit filters. The antenna switch212can selectively couple a signal from one or more of the duplexers211A to211N to an antenna port ANT. The duplexers211A to211N can be associated with different frequency bands and/or different modes of operation (e.g., different power modes, different signaling modes, etc.).

The acoustic wave filters disclosed herein can be implemented in a variety of wireless communication devices.FIG. 25Ais a schematic diagram of a wireless communication250device that includes filters253in a radio frequency front end252according to an embodiment. One or more of the filters253can be acoustic wave filter in accordance with any suitable principles and advantages disclosed herein. The wireless communication device250can be any suitable wireless communication device. For instance, a wireless communication device250can be a mobile phone, such as a smart phone. As illustrated, the wireless communication device250includes an antenna251, an RF front end252, a transceiver254, a processor255, a memory256, and a user interface257. The antenna251can transmit RF signals provided by the RF front end252. Such RF signals can include carrier aggregation signals. The antenna251can receive RF signals and provide the received RF signals to the RF front end252for processing. Such RF signals can include carrier aggregation signals. The wireless communication device250can include two or more antennas in certain instances.

The RF front end252can include one or more power amplifiers, one or more low noise amplifiers, one or more RF switches, one or more receive filters, one or more transmit filters, one or more duplex filters, one or more multiplexers, one or more frequency multiplexing circuits, the like, or any suitable combination thereof. The RF front end252can transmit and receive RF signals associated with any suitable communication standards. One or more of the filters253can include an acoustic wave filter with two types of acoustic resonators that includes any suitable combination of features of the embodiments disclosed above.

The transceiver254can provide RF signals to the RF front end252for amplification and/or other processing. The transceiver254can also process an RF signal provided by a low noise amplifier of the RF front end252. The transceiver254is in communication with the processor255. The processor255can be a baseband processor. The processor255can provide any suitable base band processing functions for the wireless communication device250. The memory256can be accessed by the processor255. The memory256can store any suitable data for the wireless communication device250. The user interface257can be any suitable user interface, such as a display with touch screen capabilities.

FIG. 25Bis a schematic diagram of a wireless communication device260that includes filters253in a radio frequency front end252and second filters263in a diversity receive module262. The wireless communication device260is like the wireless communication device250ofFIG. 25A, except that the wireless communication device260also includes diversity receive features. As illustrated inFIG. 25B, the wireless communication device260includes a diversity antenna261, a diversity module262configured to process signals received by the diversity antenna261and including filters263, and a transceiver254in communication with both the radio frequency front end252and the diversity receive module262. One or more of the second filters263can include an acoustic wave filter in accordance with any suitable principles and advantages disclosed herein.

Any of the embodiments described above can be implemented in association with mobile devices such as cellular handsets. The principles and advantages of the embodiments can be used for any systems or apparatus, such as any uplink wireless communication device, that could benefit from any of the embodiments described herein. The teachings herein are applicable to a variety of systems. Although this disclosure includes example embodiments, the teachings described herein can be applied to a variety of structures. Any of the principles and advantages discussed herein can be implemented in association with RF circuits configured to process signals having a frequency in a range from about 30 kHz to 300 GHz, such as in a frequency range from about 400 MHz to 8.5 GHz.

An acoustic wave filter including any suitable combination of features disclosed herein be arranged to filter a radio frequency signal in a 5G NR operating band within Frequency Range 1 (FR1). A filter arranged to filter a radio frequency signal in a 5G NR operating band can include two types of acoustic resonators in accordance with any principles and advantages disclosed herein. FR1 can be from 410 MHz to 7.125 GHz, for example, as specified in a current 5G NR specification. In 5G applications, an acoustic wave filter with a relatively wide pass band and relatively low insertion loss can be advantageous for implementing dual connectivity. An acoustic wave filter in accordance with any suitable principles and advantages disclosed herein can be arranged to filter a radio frequency signal in a 4G LTE operating band and/or in a filter having a passband that includes a 4G LTE operating band and a 5G NR operating band. Filters disclosed herein can filter radio frequency signals in a frequency range from about 400 MHz to 3 GHz in certain applications.

Aspects of this disclosure can be implemented in various electronic devices. Examples of the electronic devices can include, but are not limited to, consumer electronic products, parts of the consumer electronic products such as packaged radio frequency modules, radio frequency filter die, uplink wireless communication devices, wireless communication infrastructure, electronic test equipment, etc. Examples of the electronic devices can include, but are not limited to, a mobile phone such as a smart phone, a wearable computing device such as a smart watch or an ear piece, a telephone, a television, a computer monitor, a computer, a modem, a hand-held computer, a laptop computer, a tablet computer, a microwave, a refrigerator, a vehicular electronics system such as an automotive electronics system, a robot such as an industrial robot, an Internet of things device, a stereo system, a digital music player, a radio, a camera such as a digital camera, a portable memory chip, a home appliance such as a washer or a dryer, a peripheral device, a wrist watch, a clock, etc. Further, the electronic devices can include unfinished products.

Unless the context indicates otherwise, throughout the description and the claims, the words “comprise,” “comprising,” “include,” “including” and the like are to generally be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” Conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” “for example,” “such as” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and/or states. The word “coupled”, as generally used herein, refers to two or more elements that may be either directly coupled, or coupled by way of one or more intermediate elements. Likewise, the word “connected”, as generally used herein, refers to two or more elements that may be either directly connected, or connected by way of one or more intermediate elements. Additionally, the words “herein,” “above,” “below,” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the above Detailed Description using the singular or plural number may also include the plural or singular number respectively.