FBAR filter with integrated abort circuit

Abstract

Acoustic wave device (10; 20; 30; 40; 50; 60), comprising: an acoustic wave filter designed to filter a high-frequency signal; and a loop circuit coupled to the acoustic wave filter, wherein the loop circuit is configured to generate an antiphase signal to a target signal at a specific frequency, the loop circuit comprising a Lamb wave resonator (14; 34; 64; 70; 70', 70''; 70''''; 70''''; 70''''; 70''''; 70''''') which has a piezoelectric layer (15'; 15''; 15'''; 115) and an interdigital transducer electrode (16; 112; 112') arranged on the piezoelectric layer (15'; 15''; 15'''; 115), wherein the piezoelectric layer (15'; 15''; 15'''; 115) comprises free edges, one edge of the piezoelectric layer (15'; 15''; 15'''; 115) is formed with an overhang to the interdigital transducer electrode (16; 112; 112') to either suppress or scatter reflections of acoustic waves generated by the interdigital transducer electrode (16; 112; 112') from the edge of the piezoelectric layer (15; 15''; 15'''; 115).

Description

Background Technical field

[0001] Embodiments of the invention relate to acoustic wave filters. In particular, the invention relates to an acoustic wave device, a high-frequency module, a wireless communication device, and a filter. State of the art

[0002] Acoustic wave filters can filter high-frequency signals. An acoustic wave filter can comprise a variety of resonators arranged to filter a high-frequency signal. The resonators can be arranged in a ladder circuit. Examples of acoustic wave filters include surface acoustic wave (SAW) filters, volume acoustic wave (BAW) filters, and Lamb acoustic wave resonator filters. A thin-film volume acoustic wave (FBAR) filter is an example of a BAW filter. A surface-mounted volume acoustic wave resonator (solidly-mounted resonator (SMR)) filter is another example of a BAW filter.

[0003] Acoustic wave filters can be used in high-frequency electronic systems. For example, filters in the high-frequency front end of a mobile phone may include acoustic wave filters. Two acoustic wave filters can be arranged as a duplexer.

[0004] For example, US 2018 / 0152191 A1 describes a filter with a loop circuit. The described filter comprises a ladder filter having a plurality of series-armed acoustic wave elements connected in series along a signal path between the input and the output, and a plurality of parallel-armed acoustic wave elements connected between the signal path and ground, wherein each series-armed acoustic wave element and each parallel-armed acoustic wave element is a volume acoustic wave element.The filter also includes a loop circuit connected in parallel to the ladder filter between the input and the output, wherein the loop circuit comprises an acoustic wave filter, a first capacitor and a second capacitor, the first capacitor being connected to the input, the second capacitor being connected to the output, and the acoustic wave filter being connected in series between the first and the second capacitor, the acoustic wave filter comprising a first acoustic wave element and a second acoustic wave element, the first and second acoustic wave elements each having a signal electrode and a ground electrode and being arranged such that a direction from the signal electrode to the ground electrode is oriented the same way in each of the first and second acoustic wave elements.

[0005] JP H04 018806 A describes a piezoelectric thin-film device comprising a substrate, a piezoelectric layer configured with a gap between the substrate and the piezoelectric layer, and a transverse finger electrode formed on the gap on at least one surface of the piezoelectric layer. The electrode excites an elastic wave that propagates in a prescribed direction. The end portion of the gap, located on the propagation path of the elastic wave excited by the transverse finger electrode, is inclined to the propagation direction of the elastic wave. Summary

[0006] The invention is defined by the subject matter of the independent claims. Further embodiments are the subject matter of the dependent claims.

[0007] According to one aspect of the invention, an acoustic wave device is provided. The acoustic wave device comprises an acoustic wave filter configured to filter a high-frequency signal and a loop circuit coupled to the acoustic wave filter, the loop circuit being configured to generate an antiphase signal to a target signal at a specific frequency. The loop circuit comprises a Lamb wave resonator with a piezoelectric layer and an interdigital transducer electrode arranged on the piezoelectric layer. The piezoelectric layer has free edges, one edge of which is configured with an overhang towards the interdigital transducer electrode to suppress or scatter reflections of acoustic waves generated by the interdigital transducer electrode from the edge of the piezoelectric layer.

[0008] In some embodiments, the piezoelectric layer is an aluminum nitride layer.

[0009] In some embodiments, the piezoelectric layer is a lithium niobate layer.

[0010] In some embodiments, the piezoelectric layer is a lithium tantalate layer.

[0011] In some embodiments, an acoustic wave mode used in the Lamb wave resonator is the asymmetric (A0) lowest order mode, the symmetric (S0) lowest order mode, the horizontal shear (SH0) lowest order mode, an asymmetric (A1) first order mode, the symmetric (S1) first order mode, or the horizontal shear (SH1) first order mode.

[0012] In some embodiments, the Lamb wave resonator is a surface-bound resonator. The Lamb wave resonator may include Bragg reflectors.

[0013] In some embodiments, the Lamb wave resonator is a freestanding resonator.

[0014] In some embodiments, the acoustic wave filter comprises a volume acoustic wave resonator. The piezoelectric layer of the Lamb wave resonator can be made of the same material as the piezoelectric material of the volume acoustic wave resonator. The volume acoustic wave resonator can be a thin-film volume acoustic wave resonator. The volume acoustic wave resonator can be a surface-bound resonator.

[0015] In some embodiments, the acoustic wave filter includes a second Lamb wave resonator.

[0016] In some embodiments, the Lamb wave resonator and at least one resonator of the acoustic wave filter are arranged on the same semiconductor substrate.

[0017] In some embodiments, the acoustic wave filter is a transmitting filter.

[0018] In some embodiments, the acoustic wave filter is a receiving filter.

[0019] In some embodiments, the acoustic wave device further comprises a second acoustic wave filter, wherein the acoustic wave filter and the second acoustic wave filter are contained in a duplexer.

[0020] According to a further aspect of the invention, an acoustic wave device is provided. The acoustic wave device comprises an acoustic wave filter configured to filter a high-frequency signal, wherein the acoustic wave filter comprises a volume acoustic wave resonator, and a loop circuit coupled to the acoustic wave filter, wherein the loop circuit is configured to generate an antiphase signal to a target signal at a specific frequency, wherein the loop circuit comprises a Lamb wave resonator with a piezoelectric layer, the piezoelectric layer having free edges, one edge of the piezoelectric layer being configured with an overhang towards the interdigital transducer electrode to suppress or scatter reflections of acoustic waves from the edge of the piezoelectric layer.

[0021] In some embodiments, the volume acoustic wave resonator is a thin-film volume acoustic wave resonator. The thin-film volume acoustic wave resonator and the Lamb wave resonator can comprise corresponding piezoelectric layers formed from the same material. The respective piezoelectric layers can comprise or consist of aluminum nitride. The thin-film volume acoustic wave resonator and the Lamb wave resonator can be arranged on the same silicon substrate.

[0022] In some embodiments, the volume acoustic wave resonator is a surface-bound resonator. The surface-bound resonator and the Lamb wave resonator can be arranged on the same silicon substrate.

[0023] In some embodiments, the acoustic wave filter is a transmitting filter.

[0024] In some embodiments, the acoustic wave filter is a receiving filter.

[0025] In some embodiments, the acoustic wave device includes a second acoustic wave filter, wherein the acoustic wave filter and the second acoustic wave filter are contained in a duplexer.

[0026] According to a further aspect of the invention, a high-frequency module is provided. The high-frequency module comprises a duplexer, which includes an acoustic wave device, wherein the acoustic wave device comprises an acoustic wave filter configured to filter a high-frequency signal, and a loop circuit coupled to the acoustic wave filter, wherein the loop circuit is configured to generate an antiphase signal to a target signal at a specific frequency, and wherein the loop circuit comprises a Lamb wave resonator with a piezoelectric layer and an interdigital transducer electrode arranged on the piezoelectric layer, wherein the piezoelectric layer comprises free edges, one edge of which is configured to suppress or scatter reflections of acoustic waves generated by the interdigital transducer electrode from the edge of the piezoelectric layer.and a high-frequency switch arranged to allow a high-frequency signal to pass through, which is assigned to a port of the duplexer.

[0027] In some embodiments, the high-frequency module further includes a power amplifier, with the high-frequency switch being coupled in a signal path between the power amplifier and the duplexer.

[0028] In some embodiments, the high-frequency switch is an antenna switch.

[0029] In some embodiments, the high-frequency switch is a band selector switch.

[0030] According to a further aspect of the invention, a wireless communication device is provided. The wireless communication device comprises a high-frequency front end with an acoustic wave device, wherein the acoustic wave device comprises an acoustic wave filter configured to filter a high-frequency signal, and a loop circuit coupled to the acoustic wave filter, wherein the loop circuit is configured to generate an antiphase signal to a target signal at a specific frequency, and wherein the loop circuit comprises a Lamb wave resonator with a piezoelectric layer and an interdigital transducer electrode arranged on the piezoelectric layer, wherein the piezoelectric layer comprises free edges, one edge of which is configured with an overhang to the interdigital transducer electrode to absorb reflections of acoustic waves generated by the interdigital transducer electrode.to suppress or scatter signals from the edge of the piezoelectric layer, and includes an antenna in communication with the high-frequency front end.

[0031] According to a further aspect of the invention, a filter is provided. The filter comprises: an input terminal; an output terminal; a main volume acoustic wave filter circuit connected between the input terminal and the output terminal, wherein the main volume acoustic wave filter circuit has a first phase characteristic, a first passband, and a first stopband; and a phase-shift circuit connected in parallel to the main volume acoustic wave filter circuit between the input terminal and the output terminal, wherein the phase-shift circuit comprises a first capacitor element, a second capacitor element, and a Lamb-mode-coupled resonator connected in series between the first capacitor element and the second capacitor element, wherein the Lamb-mode-coupled resonator comprises at least two interdigital converter electrodes.which are arranged separately from one another on a piezoelectric layer in a single acoustic wave path along which acoustic waves propagate through the Lamb mode-coupled resonator, wherein the piezoelectric layer has free edges, wherein an edge of the piezoelectric layer is configured with an overhang to the interdigital transducer electrode such that it either suppresses or scatters reflections of acoustic waves generated by the Lamb mode-coupled resonator from the edge of the piezoelectric layer, wherein the phase-shift circuit has a second phase characteristic which is opposite to the first phase characteristic in an attenuation band which corresponds to at least one section of the first stopband.

[0032] According to a further aspect of the invention, a filter is provided. The filter comprises: an input terminal; an output terminal; a main thin-film volume acoustic wave resonator filter circuit connected between the input terminal and the output terminal, wherein the main thin-film volume acoustic wave resonator filter circuit has a first phase characteristic, a first passband, and a first stopband; and a phase-shifting circuit connected in parallel to the main thin-film volume acoustic wave resonator filter circuit between the input terminal and the output terminal, wherein the phase-shifting circuit comprises a first capacitor element, a second capacitor element, and a Lamb-mode-coupled resonator connected in series between the first capacitor element and the second capacitor element, wherein the Lamb-mode-coupled resonator comprises at least two interdigital converter electrodes.which are arranged separately from one another on a piezoelectric layer in a single acoustic wave path along which acoustic waves propagate through the Lamb mode-coupled resonator, wherein the piezoelectric layer has free edges, wherein an edge of the piezoelectric layer is configured with an overhang to the interdigital transducer electrode such that it either suppresses or scatters reflections of acoustic waves generated by the Lamb mode-coupled resonator from the edge of the piezoelectric layer, wherein the phase-shift circuit has a second phase characteristic which is opposite to the first phase characteristic in an attenuation band which corresponds to at least one section of the first stopband. Brief description of the drawings

[0033] Embodiments of this disclosure are now described by way of example without limitation with reference to the attached drawings. Fig. Figure 1 is a cross-sectional diagram of an acoustic wave device comprising a Lamb wave acoustic wave element of a loop circuit and a thin-film volume acoustic wave resonator (FBAR) of an acoustic wave filter according to one embodiment; Fig. Figure 2 is a cross-sectional diagram of an acoustic wave device comprising a Lamb wave acoustic wave element of a loop circuit and a Lamb wave resonator of an acoustic wave filter according to one embodiment; Fig. Figure 3 is a cross-sectional diagram of an acoustic wave device comprising a surface-bound Lamb wave acoustic wave element of a loop circuit and an FBAR of an acoustic wave filter according to one embodiment; Fig. Figure 4 is a cross-sectional diagram of an acoustic wave device comprising a surface-bound lamb wave acoustic wave element of a loop circuit and a lamb wave resonator of an acoustic wave filter according to one embodiment; Fig. Figure 5 is a cross-sectional diagram of an acoustic wave device comprising a lamb wave acoustic wave element of a loop circuit and a surface-bound lamb wave resonator of an acoustic wave filter according to one embodiment; Fig. Figure 6 is a cross-sectional diagram of an acoustic wave device comprising a surface-bound Lamb wave acoustic wave element of a loop circuit and a surface-bound resonator (SMR) of an acoustic wave filter according to an embodiment; Fig. Figure 7A illustrates a cross-section of a Lamb wave acoustic wave element with a grounded electrode and free edges; Fig. Figure 7B illustrates a cross-section of a Lamb wave acoustic wave element with a floating electrode and free edges; Fig. Figure 7C illustrates a cross-section of a Lamb wave acoustic wave element without an electrode on one side of a piezoelectric layer facing an IDT electrode and including free edges; Fig. Figure 7D illustrates a cross-section of another Lamb wave acoustic wave element that includes free edges; Fig. Figure 7E illustrates a cross-section of another Lamb wave acoustic wave element that includes free edges; Fig. Figure 7F illustrates a cross-section of another Lamb wave acoustic wave element that includes free edges; Fig. Figure 8 is a schematic diagram of a duplexer with a loop circuit for a transmit filter; Fig. 9 is a curve that provides isolation for the duplexer of Fig. 8 compares to a corresponding duplexer without a loop circuit; Fig. Figure 10 is a schematic diagram of a duplexer with a loop circuit for a receive filter; Fig. 11A is a curve that provides isolation for the duplexer of Fig. 10 compares to a corresponding duplexer without a loop circuit; Fig. 11B is a curve that provides receive band suppression for the duplexer of Fig. 10 compares to a corresponding duplexer without a loop circuit; Fig. Figure 12 is a schematic diagram of a duplexer with a first loop circuit for a transmit filter and a second loop circuit for a receive filter; Fig. 13 is a diagram that shows isolation for the duplexer of Fig. 12 compares to a corresponding duplexer without loop circuits; Fig. Figure 14 is a top view of an embodiment of a Lamb wave acoustic wave resonator; Fig. Figure 15 is a top view of another embodiment of a Lamb wave acoustic wave element; Fig. Figure 16 is a top view of another embodiment of a Lamb wave acoustic wave element; Fig. Figure 17 is a top view of another embodiment of a Lamb wave acoustic wave element; Fig. 18A is a schematic block diagram of a module comprising an antenna switch and a duplexer with a Lamb wave loop circuit; Fig. 18B is a schematic block diagram of a module comprising a power amplifier, a switch and a duplexer with a Lamb wave loop circuit; Fig. 18C is a schematic block diagram of a module comprising a power amplifier, a switch, a duplexer with a Lamb wave loop circuit, and an antenna switch; and Fig. Figure 19 is a schematic block diagram of a wireless communication device comprising a duplexer with a Lamb wave loop circuit. Detailed description of specific embodiments

[0034] The following description of certain embodiments presents various descriptions of specific embodiments. However, the innovations described herein can be implemented in a variety of ways, for example, through the definition and scope of the claims. Reference is made in this description to the drawings, in which the same reference numerals may denote identical or functionally similar elements. It is understood that the elements shown in the figures are not necessarily to scale. Furthermore, it is assumed that certain embodiments may include more elements than are shown in a drawing and / or a subset of the elements shown in a drawing. In addition, some embodiments may include any suitable combination of features from two or more drawings.

[0035] An acoustic wave filter may include a loop circuit to eliminate an unwanted frequency component. The loop circuit can improve transmit / receive isolation and attenuation for a specific frequency range. The loop circuit can apply a signal of approximately the same amplitude but opposite phase to a signal component to be canceled. Surface acoustic wave (SAW) loop circuits have been used to improve the isolation and attenuation characteristics of SAW filters. Some loop circuits for thin-film volume acoustic wave resonator (FBAR) filters and other volume acoustic wave (BAW) filters incorporate LC circuits. Such LC circuits may include one or more capacitors and / or one or more inductors with a relatively large physical footprint and / or may be implemented externally on a chip that includes the BAW filter coupled to the loop circuit.

[0036] Lamb wave loop circuits are disclosed. Lamb wave loop circuits can be integrated with BAW filters and / or duplexers. For example, aluminum nitride (AIN) lamb wave loop circuits can be integrated with AIN-FBAR filters. Such lamb wave loop circuits can improve transmit / receive (Tx / Rx) isolation and attenuation characteristics in any desired frequency range. A lamb wave loop circuit can generate an anti-phase RF signal to cancel out a target signal at a desired frequency. The lamb wave loop circuits discussed herein can improve the isolation and attenuation of RF acoustic filters such as BAW filters (e.g., FBAR filters or SMR filters), SAW filters, and lamb wave filters.

[0037] A Lamb wave resonator can combine features of a SAW resonator and a BAW resonator. A Lamb wave resonator typically incorporates an interdigital converter (IDT) electrode, similar to a SAW resonator. Accordingly, the frequency of the Lamb wave resonator can be lithographically defined. Like a BAW filter, a Lamb wave resonator can achieve a relatively high quality factor (Q) and a relatively high phase velocity (e.g., through a suspension structure). A Lamb wave resonator incorporating a piezoelectric AIN layer can be relatively easily integrated with other circuits, for example, because AIN process technology can be compatible with complementary metal-oxide-semiconductor (CMOS) process technology.AIN lambda resonators can overcome a relatively minor resonant frequency limiting and integration challenge associated with SAW resonators, and can also overcome multi-frequency capability challenges associated with BAW resonators. Some lambda resonator topologies are based on acoustic reflection from periodic reflection gratings. Others are based on acoustic reflection from suspended free edges of a piezoelectric layer.

[0038] An AIN lambda loop circuit can be directly integrated into AIN-FBAR and / or other BAW filters during fabrication to form such filters. Such integration can also be achieved for other suitable piezoelectric layers. Accordingly, a lambda loop circuit can provide a cost-effective and efficient way to incorporate a loop circuit for a BAW filter. A lambda loop circuit for a BAW filter can be implemented in a relatively small space. For example, a lambda loop circuit can have a smaller physical footprint than a loop circuit based on an LC circuit. A smaller physical footprint can reduce power consumption and / or manufacturing costs.

[0039] A loop circuit can include a freestanding Lamb wave resonator or a surface-bound Lamb wave resonator. Exemplary acoustic wave devices comprising such Lamb wave resonators and resonators of an acoustic wave filter coupled to the loop circuit are described with reference to the Fig. 1 to 6 are described. Any suitable combination of features from these examples can be combined with each other.

[0040] Fig. Figure 1 is a cross-sectional diagram of an acoustic wave device 10 comprising a thin-film volume acoustic wave resonator (FBAR) 12 of an acoustic wave filter and a lamb wave resonator 14 of a loop circuit according to an embodiment.

[0041] The FBAR 12 comprises a piezoelectric layer 15, an upper electrode 7 on an upper surface of the piezoelectric layer 15, and a lower electrode 17 on a lower surface of the piezoelectric layer 15. The piezoelectric layer 15 can be a thin film. The piezoelectric layer 15 can be an aluminum nitride layer. In other cases, the piezoelectric layer 15 can be any suitable piezoelectric layer. The piezoelectric layer 15 is arranged on a substrate 19 and defines a cavity 18 between a lower surface of the piezoelectric layer 15 and the substrate 19. The lower electrode is arranged in the cavity 18. The cavity 18 can be filled with air or another gas, or, in other embodiments, can be evacuated to form a vacuum cavity.

[0042] The Lamb wave resonator 14 incorporates features of a SAW resonator and an FBAR. As shown, the Lamb wave resonator 14 comprises a piezoelectric layer 15', an interdigital transducer electrode (IDT) 16 on the piezoelectric layer 15', and a lower electrode 17' located on a lower surface of the piezoelectric layer 15'. The piezoelectric layer 15' can be a thin film. The piezoelectric layer 15' can be an aluminum nitride layer. In other cases, the piezoelectric layer 15' can be any suitable piezoelectric layer. The frequency of the Lamb wave resonator can be based on the geometry of the IDT 16. The electrode 17' can be grounded in certain cases. In other cases, the electrode 17' can be floating. An air cavity 18' is arranged between the electrode 17' and a semiconductor substrate 19. Any suitable cavity can be used instead of the 18' air cavity, e.g.a vacuum cavity or a cavity filled with another gas.

[0043] In the acoustic wave device 10, the piezoelectric layer 15 of the FBAR 12 can be made of the same or similar material, e.g., AIN, lithium niobate, or lithium tantalate, wherein the dimensions of the piezoelectric layer 15' of the Lamb wave resonator 14 can be similar or identical, which can facilitate the parallel fabrication of the two devices. The cavities 18, 18' of the FBAR 12 and the Lamb wave resonator 14 can have similar or identical dimensions and be filled with the same or similar gas, or one or both cavities 18, 18' can be a vacuum cavity. The Lamb wave resonator 14 and the FBAR 12 can be arranged on the same semiconductor substrate 19. The semiconductor substrate 19 can be a silicon substrate.It is preferred that, due to the structural similarity of the FBAR 12 used in the acoustic wave filter and the Lamb wave resonator 14 used in the loop circuit, the components of the loop circuit can be added to the acoustic wave filter with few, if any, additional processing steps.

[0044] Fig. Figure 2 is a cross-sectional diagram of an acoustic wave device 20 comprising a Lamb wave resonator 14 of a loop circuit and a Lamb wave resonator 24 of an acoustic wave filter according to one embodiment. The Lamb wave resonator 24 may have the same or a similar structure as the Lamb wave resonator 14, although in some embodiments the Lamb wave resonator 14 of the loop circuit and the Lamb wave resonator 24 of the acoustic wave filter have different operating frequencies. The Lamb wave resonators 14 and 24 may share a substrate 19, e.g., a silicon substrate, wherein the respective piezoelectric layers 15', 25 may be formed of the same or similar material, e.g., aniline, lithium niobate, or lithium tantalate, and / or have the same or similar dimensions, which may facilitate the parallel fabrication of the two devices.The respective cavities 18', 28 can have similar or identical dimensions and be filled with the same or similar gas, or one or both of the cavities 18', 28 can be a vacuum cavity. It is preferred that, due to the structural similarity of the Lamb wave resonator 24 used in the acoustic wave filter and the Lamb wave resonator 14 used in the loop circuit, the components of the loop circuit can be added to the acoustic wave filter with few, if any, additional processing steps.

[0045] Fig. Figure 3 is a diagram of a cross-section of an acoustic wave device 30 comprising a surface-bound Lamb wave resonator 34 of a loop circuit and an FBAR 12 of an acoustic wave filter according to one embodiment. The FBAR 12 of Fig. 3 can be similar to or the same as FBAR 12 from Fig. Be 1.

[0046] The Lamb wave resonator 34 combines the properties of a SAW resonator and an SMR. As shown, the Lamb wave resonator 34 comprises a piezoelectric layer 15", an IDT 36 on the piezoelectric layer 15", and a lower electrode 17'. The piezoelectric layer 15" can be an aluminum nitride layer. In other cases, the piezoelectric layer 15" can be any other suitable piezoelectric layer. The operating frequency of the Lamb wave resonator can be based on the geometry of the IDT 36. The electrode 17' can be grounded in certain cases. In other cases, the electrode 17' can be floating. Bragg reflectors 35 are arranged between the electrode 17' and a semiconductor substrate 19. Any suitable Bragg reflectors can be used. For example, the Bragg reflectors can be SiO2 / W.

[0047] In the acoustic wave device 30, the Lamb wave resonator 34 and the FBAR 12 can have piezoelectric layers formed from the same or similar material, for example, AIN, lithium niobate, or lithium tantalate. The piezoelectric layer of the Lamb wave resonator 34 and the piezoelectric layer of the FBAR 12 can be arranged on the same semiconductor substrate 19. The semiconductor substrate 19 can be a silicon substrate.

[0048] Fig. Figure 4 is a diagram of a cross-sectional view of an acoustic wave device 40 comprising a surface-bound Lamb wave resonator 34 of a loop circuit and a Lamb wave resonator 44 of an acoustic wave filter according to one embodiment. The Lamb wave resonator 44 is a free-standing Lamb wave resonator. The surface-bound Lamb wave resonator 34 and the Lamb wave resonator 44 can comprise the same piezoelectric material, for example, AIN, lithium niobate, or lithium tantalate. The surface-bound Lamb wave resonator 34 and the Lamb wave resonator 44 can be arranged on the same semiconductor substrate 19. The surface-bound Lamb wave resonator 34 can be substantially similar to the surface-bound Lamb wave resonator 34 from Figure 4. Fig. 3. The Lamb wave resonator 44 can essentially be compared to the Lamb wave resonator 24. Fig. 2 be similar.

[0049] Fig. Figure 5 is a diagram of a cross-sectional view of an acoustic wave device 50 comprising a Lamb wave resonator 14 of a loop circuit and a surface-bound Lamb wave resonator 52 of an acoustic wave filter according to one embodiment. The surface-bound Lamb wave resonator 52 incorporates features of a SAW resonator and an SMR. The surface-bound Lamb wave resonator 52 includes an IDT on a piezoelectric layer, Bragg reflectors, and an electrode between the piezoelectric layer and the Bragg reflectors. As shown, the surface-bound Lamb wave resonator 52 comprises a piezoelectric layer, such as an AIN layer, and SiO2 / W Bragg reflectors. Any other suitable Bragg reflectors can alternatively or additionally be integrated into the surface-bound Lamb wave resonator 52. The Lamb wave resonator can be substantially similar to the Lamb wave resonator 14. Fig. 1. The surface-bound Lamb wave resonator 52 can essentially be similar to the surface-bound Lamb wave resonator 34. Fig. 3 be similar.

[0050] Fig. Figure 6 is a diagram of a cross-sectional view of an acoustic wave device 60 comprising a surface-bound Lamb wave resonator 64 of a loop circuit and an SMR 62 of an acoustic wave filter according to one embodiment. The surface-bound Lamb wave resonator 64 is structurally similar to the SMR 62, except that the surface-bound Lamb wave resonator 64 comprises an IDT 16 arranged on the piezoelectric layer 15''', whereas the SMR 62 comprises an electrode of a different shape on the piezoelectric layer 15''''. The Bragg reflectors 65 for the surface-bound Lamb wave resonator 64 and the SMR 62 may be separated by semiconductor material of the semiconductor substrate 19.It is preferred that, due to the structural similarity of the SMR 62 used in the acoustic wave filter and the surface-bound Lamb wave resonator 64 used in the loop circuit, the components of the loop circuit can be added to the acoustic wave filter with few, if any, additional processing steps.

[0051] Lamb wave resonators can incorporate an IDT mounted on a piezoelectric layer with free edges. The suspended free edges of the piezoelectric layer can generate acoustic wave reflections to form a resonant cavity in such resonators. Fig. Figures 7A to 7F are diagrams of cross-sectional areas of Lamb wave resonators with free edges. A Lamb wave resonator in a loop circuit can be implemented using all the appropriate principles and advantages of any of the Lamb wave resonators of the Fig. 7A to 7F are realized. Although the Lamb wave resonators of the Fig. Since 7A to 7F are freestanding resonators, all suitable principles and advantages of these Lamb wave resonators can be transferred to other Lamb wave resonators.

[0052] Fig. Figure 7A illustrates a Lamb wave resonator 70 comprising an IDT 112, a piezoelectric layer 115, and an electrode 116. The IDT 112 is located on the piezoelectric layer 115. In the cross-section shown, ground and signal electrode fingers are alternately contained within the IDTs, as indicated by the different cross-hatching. The piezoelectric layer 115 has free edges on opposite sides of the IDT 112. The electrode 116 and the IDT 112 are located on opposite sides of the piezoelectric layer 115. The piezoelectric layer 115 can be, for example, AIN. The electrode 116 can be grounded.

[0053] Fig. Figure 7B illustrates a Lamb wave resonator 70'. The Lamb wave resonator 70' is like the Lamb wave resonator 70 from Fig. 7A designed, except that the Lamb wave resonator 70' includes a potential-free electrode 116'.

[0054] Fig. Figure 7C illustrates a Lamb wave resonator 70'' without an electrode on one side of the piezoelectric layer 115, which is opposite the IDT 112.

[0055] Fig. Figure 7D illustrates a Lamb wave resonator 70''' which includes an IDT 117 on a second side of the piezoelectric layer 115, opposite a first side on which the IDT 112 is arranged. The signal and ground electrode fingers of the IDT electrodes are offset relative to each other in IDTs 112 and 117, as shown by the different cross-hatching.

[0056] Fig. Figure 7E illustrates a Lamb wave resonator 70'''' which includes an IDT 117' on a second side of the piezoelectric layer 115, opposite a first side on which the IDT 112 is arranged. The signal and ground electrode fingers of the IDT electrodes are matched for the IDTs 112 and 117', as shown by the different cross-hatching.

[0057] Fig. Figure 7F illustrates a Lamb wave resonator 70'''', which includes an IDT 117'' on a second side of the piezoelectric layer 115, opposite a first side on which the IDT 112' is arranged. In the cross-section shown, the IDT 112' comprises only signal electrodes and the IDT 117'' only ground electrodes.

[0058] The Lamb wave resonator loop circuits described herein can be coupled with an acoustic wave filter. For example, a Lamb wave resonator can be coupled with an acoustic wave filter of a duplexer or another multiplexer (e.g., a quadplexer, hexaplexer, octoplexer, etc.). Fig. 8, Fig. 10 and Fig. Figure 12 are schematic diagrams illustrating exemplary duplexers comprising a Lamb wave loop circuit coupled with an acoustic wave filter. All suitable principles and advantages relating to those explained below are shown. Fig. 1 to 7F and Fig. Sections 14 to 17 are discussed and / or illustrated, and each of the exemplary duplexers can be applied to the Fig. 8, Fig. 10 and Fig. 12 are applied.

[0059] Fig. Figure 8 is a schematic diagram of a duplexer 80 with a loop circuit 83 for a transmit filter 82. The duplexer 80 comprises a transmit filter 82, a receive filter 84, and a loop circuit 83. The transmit filter 82 and the receive filter 84 are coupled at a node located in Fig. 8 is an antenna node. An antenna 85 is coupled to the antenna node of the duplexer 80. A shunt inductor L1 can be coupled between the antenna 85 and ground.

[0060] The transmit filter 82 can filter an RF signal received at the transmit port TX for transmission via the antenna 85. A series inductor L2 can be coupled between the transmit port TX and the acoustic wave resonators of the transmit filter 82. The transmit filter 82 is an acoustic wave filter comprising acoustic wave resonators arranged as a conductor filter. The transmit filter 82 includes the series resonators T01, T03, T05, T07, T09 and the shunt resonators T02, T04, T06, T08. The transmit filter 82 can include any number of series resonators and any number of shunt resonators. The acoustic wave resonators of the transmit filter 82 can include BAW resonators such as FBARs and / or SMRs. In some cases, the acoustic wave resonators of the transmit filter 82 may include SAW resonators or Lamb wave resonators. In certain applications, the resonators of the transmit filter 82 may include two or more types of resonators (e.g.,one or more SAW resonators and one or more BAW resonators).

[0061] A loop circuit 83 is coupled to the transmit filter 82. The loop circuit 83 can be coupled to an input resonator T01 and an output resonator T09 of the transmit filter. In some other cases, the loop circuit 83 can be coupled to a different node of the ladder circuit than shown in the figure. The loop circuit 83 can apply a signal with approximately the same amplitude and opposite phase to a signal component to be canceled. The loop circuit 83 includes Lamb wave resonators 86 and 87, which are each coupled to the transmit filter 82 via capacitors CAP02 and CAP01, respectively. All suitable principles and advantages of the Lamb wave resonators of a loop circuit described herein can be implemented in the loop circuit 83.

[0062] The receive filter 84 can filter an RF signal received by the antenna 85 and deliver a filtered RF signal to a receive port RX. The receive filter 84 is an acoustic wave filter comprising acoustic wave resonators arranged as a ladder filter. The receive filter 84 includes series resonators R01, R03, R05, R07, R09 and shunt resonators R02, R04, R06, R08. The receive filter 84 can include any number of series resonators and any number of shunt resonators. The acoustic wave resonators of the receive filter 84 can include BAW resonators such as FBARs and / or SMRs. In some cases, the acoustic wave resonators of the receive filter 84 can include SAW resonators or Lamb wave resonators. In certain applications, the resonators of the receive filter 84 may include two or more types of resonators (e.g., one or more SAW resonators and one or more BAW resonators).A series inductor L3 can be coupled between the acoustic wave resonators of the receiving filter 84 and the receiving port RX.

[0063] Fig. 9 is a diagram showing the insulation properties of the duplexer 80 from Fig. 8 compares the isolation properties of a corresponding duplexer without a loop circuit. The acoustic wave properties of the symmetrical (S0) lowest-order Lamb wave mode for an AIN Lamb wave resonator were used to investigate the loop circuits for BAW filters. The AIN Lamb wave S0 mode was measured at a velocity of ~9000 m / s and a K 2 Assumed to be ~2%. A Band-7 BAW duplexer was used to generate the predicted example. The curve in Fig. Figure 9 shows that the loop circuit 83 improves receive isolation. The improvement can be about 5 decibels (dB) in certain cases, as shown in Fig. 9 is shown.

[0064] Fig. Figure 10 is a schematic diagram of a duplexer 100 with a loop circuit for a receive filter 84. The duplexer 100 is like the duplexer 80 made of Fig. 8, except that the duplexer 100 includes a loop circuit 103 for the receive filter 84. The loop circuit 103 is coupled to the receive filter 84. The loop circuit 103 can be coupled to an input resonator R09 and an output resonator R01 of the receive filter 84. In some other cases, the loop circuit 103 can be coupled to a different node of the ladder circuit of the receive filter 84 than shown. The loop circuit 103 includes the Lamb wave resonators 106 and 107, which are each coupled to the receive filter 84 via the capacitors CAP04 and CAP03, respectively. All suitable principles and advantages of the Lamb wave resonators of a loop circuit described herein can be implemented in the loop circuit 103.

[0065] Fig. 11A is a diagram showing the insulation properties for the Duplexer 100 from Fig. 10 compares the isolation properties of a corresponding duplexer without a loop circuit. For the generation of the diagrams of Fig. 11A and Fig. In 11B, the same assumptions were used as for generating the curve of the Fig. 9. The curve of Fig. Figure 11A shows that the loop circuit 103 improves the transmit isolation.

[0066] Fig. Figure 11B is a diagram showing the receive band suppression for the Duplexer 100 from Fig. Figure 10 compares the band suppression of a corresponding duplexer without a loop circuit. This curve illustrates that the loop circuit 103 can suppress the interference at a lower frequency range for the receive band.

[0067] Fig. Figure 12 is a schematic diagram of a duplexer 120 with a first loop circuit 83 for a transmit filter 82 and a second loop circuit 103 for a receive filter 84. Fig. Figure 12 illustrates that separate loop circuits can be implemented for a transmit filter and a receive filter. A loop circuit can be implemented for an acoustic wave filter to bring a parameter of the acoustic wave filter within a specification. For example, a loop circuit can be implemented to reduce the isolation of an acoustic wave filter to less than -60 dB in order to meet an isolation specification, if the acoustic wave filter would otherwise not meet the isolation specification.

[0068] Fig. Figure 13 is a diagram showing the insulation properties of the duplexer 120. Fig. Figure 12 compares the isolation characteristics of a corresponding duplexer without loop circuits. This diagram shows that the loop circuits 83 and 103 of the duplexer 120 improve both transmit and receive isolation.

[0069] A top view of an embodiment of a Lamb wave resonator 14, which can be used in one of the embodiments disclosed herein, is shown in Fig. 14 shown. In the Lamb wave resonator 14 of Fig. The edges 15E of the piezoelectric layer 15' are parallel to each other and to the electrode fingers of the IDT 16. The distance between the edges 15E of the piezoelectric layer 15' and the outermost electrode fingers on both sides of the IDT 16 (the "overhang") is precisely controlled to be, for example, λ / 4, where λ is the wavelength of the acoustic wave excited by the IDT 16. If the overhang is not set exactly to the desired value, e.g., λ / 4, the phase of the acoustic waves reflected from the edges 15E may deviate significantly from the ideal, thus reducing the quality factor Q of the resonator 14. If the overhang is not set exactly to the desired value, the excitation frequency f of the resonator may be shifted relative to that which would be expected based on the distance p of the fingers of the IDT 16 (f = u). p / 2p, u p(the Lamb wave phase velocity in the resonator). If the edges 15E of the piezoelectric layer 15' are not exactly parallel to each other and to the electrode fingers of the IDT 16, acoustic waves reflected from the edges 15E cannot constructively interfere with the acoustic waves generated by the IDT 16 before reflection at the edges 15E, or with acoustic waves that have been reflected multiple times from the edges 15E of the piezoelectric layer 15'. Small deviations in the alignment of the edges 15E of the piezoelectric layer 15' with the fingers of the IDT 16 can thus reduce the Q of the Lamb wave resonator 14 and generate undesirable, interfering vibration modes.

[0070] In various embodiments, the attenuation signal generated in a loop circuit of a duplexer need not be very strong to adequately suppress unwanted signal components within the duplexer. For example, in some embodiments, the attenuation signal generated in a loop circuit of a duplexer can be 40 dB or more lower in power than a main passband signal through the duplexer's filters. Accordingly, a Lamb wave resonator in a loop circuit of a duplexer need not exhibit low loss or a high Q. Instead of precisely controlling the phase and direction of acoustic wave reflections from the edges 15E of the piezoelectric layer 15' (by controlling the width and orientation of the overhang), it can be much simpler to suppress or scatter the reflections.The suppression or scattering of acoustic wave reflections from the edges 15E of the piezoelectric layer 15' can be achieved by angling, roughening, or otherwise modifying the edges 15E so that waves are attenuated, scattered, or reflected, returning incoherently to the IDT 16. Lamb wave resonators that suppress or scatter acoustic wave reflections from the edges 15E of the piezoelectric layer 15' may exhibit less variation in Q and / or frequency response than Lamb wave resonators where attempts are made to strictly control the width and orientation of the overhang due to manufacturing variations that can lead to deviations from the ideal width and orientation of the overhang.

[0071] An embodiment of a Lamb-mode resonator 14, designed to suppress or scatter reflections of acoustic waves from the edges 15E of the piezoelectric layer 15', is shown in top view in Fig. Figure 15 shows that the edges 15E of the piezoelectric layer 15' are tilted or angled relative to the direction of extension of the electrode fingers of the IDT 16. The degree of inclination of both edges 15E is shown as equal, but the degree of inclination of one edge 15E may differ from the degree of inclination of the other edge 15E in some embodiments. The width of the overhang (distance D in Fig. 15) is not important and can be the same or different for the different sides of the piezoelectric layer 15' if desired.

[0072] Another embodiment of a Lamb-mode resonator 14, designed to suppress or scatter reflections of acoustic waves from the edges 15E of the piezoelectric layer 15', is shown in top view in Fig. Figure 16 illustrates this. In this embodiment, the edges 15E of the piezoelectric layer 15' are not entirely straight, but comprise several straight sections inclined at different angles with respect to the extension direction of the electrode fingers of the IDT 16. The adjacent straight sections of the edges 15E meet at acute angles. The edges 15E with different degrees of inclination or angle can generate an incoherent reflection of acoustic waves from the edges 15E of the piezoelectric layer 15'. As in the embodiment of Fig. 15 the width of the overhang (distance D) is not important and can be the same or different for the different sides of the piezoelectric layer 15' if desired.

[0073] Another embodiment of a Lamb-mode resonator 14, designed to suppress or scatter reflections of acoustic waves from the edges 15E of the piezoelectric layer 15', is shown in top view in Fig. 17. This embodiment is similar to that of Fig. 16, wherein, however, the edges 15E comprise several curved sections instead of straight sections that meet at acute angles. The various edges 15E can have different sections with different lengths or degrees of curvature. The curved edges 15E can generate an incoherent reflection of acoustic waves from the edges 15E of the piezoelectric layer 15'. As in the embodiment of Fig. 15 the width of the overhang (distance D) is not important and can be the same or different for the different sides of the piezoelectric layer 15' if desired.

[0074] In various embodiments, each of the elements in the Fig. The Lamb-mode resonators 14 shown in Figures 15 to 17 are modified such that one edge 15E is straight and optionally aligned with the electrode fingers of the IDT 16, while the other edge 15E is configured as shown to suppress or scatter reflections of acoustic waves from the edges 15E of the piezoelectric layer 15'. In further embodiments, a Lamb-mode resonator can have an edge, as shown in one of the Fig. 14 to 17 shown, and an opposite edge, as in another of the Fig. Figures 14 to 17 are shown.

[0075] It should be assumed that, although the in the Fig. Lamb wave devices shown in Figures 15 to 17 may be referred to as Lamb wave resonators, in some embodiments the suppression or scattering of reflections of acoustic waves from the edges 15E of the piezoelectric layer 15' in these devices may be significant enough to substantially or completely prevent the devices from forming resonances at their operating frequency, which is why these devices may alternatively be referred to as Lamb wave acoustic wave elements or Lamb wave acoustic wave devices.

[0076] The acoustic wave devices and / or loop circuits described herein can be implemented in a variety of encapsulated modules. Some exemplary packaged modules are now discussed, in which all suitable principles and advantages of the Lamb wave loop circuits presented herein can be implemented. Fig. 18A, Fig. 18B and Fig. 18C are schematic block diagrams of illustrated encapsulated modules according to certain embodiments.

[0077] Fig. Figure 18A is a schematic block diagram of a module 180 comprising a duplexer 182 with a Lamb wave loop circuit and an antenna switch 183. The module 180 may include a housing that encloses the illustrated elements. The duplexer 182 with the Lamb wave loop circuit and the antenna switch 183 may be arranged on the same packing substrate. The packing substrate may, for example, be a laminate substrate. The duplexer 182 may include a Lamb wave loop circuit according to the suitable principles and advantages described herein. The antenna switch 183 may be a multi-path radio frequency switch. The antenna switch 183 may selectively couple a node of the duplexer 182 electrically to an antenna terminal of the module 180.

[0078] Fig. Figure 18B is a schematic block diagram of a module 184 comprising a power amplifier 185 (“PA”), a switch 186, and a duplexer 182 with a Lamb wave loop circuit. The power amplifier 185 can amplify a high-frequency signal. The switch 186 can selectively couple an output of the power amplifier 185 electrically to a transmit port of the duplexer 182. The duplexer 182 can include a Lamb wave loop circuit according to the suitable principles and advantages described herein.

[0079] Fig. 18C is a schematic block diagram of a module 187, which includes the power amplifier 185 (“PA”), a switch 186, a duplexer 182 with a Lamb wave loop circuit, and an antenna switch 183. The module 187 is similar to the module 184 from Fig. 18B, however, module 187 additionally includes the antenna switch 183.

[0080] Fig.Figure 19 is a schematic block diagram of a wireless communication device 200 comprising a duplexer 203 with a Lamb wave loop circuit according to one or more embodiments. The wireless communication device 200 can be any suitable wireless communication device. For example, a wireless communication device 200 can be a mobile phone, such as a smartphone. As shown, the wireless communication device 200 comprises an antenna 201, an RF front end 202, an RF transceiver 204, a processor 205, and a memory 206. The antenna 201 can transmit RF signals provided by the RF front end 202. The antenna 201 can provide received RF signals to the RF front end 202 for processing.

[0081] The RF front end 202 can comprise one or more power amplifiers, one or more low-noise amplifiers, RF switches, receive filters, transmit filters, duplex filters, filters of a multiplexer, filters of a diplexer or other frequency-division multiplexing circuit, or a suitable combination thereof. The RF front end 202 can transmit and receive RF signals compatible with all suitable communication standards. Any of the acoustic wave devices and / or Lamb wave loop circuits described herein can be implemented in the RF front end 202.

[0082] The RF transceiver 204 can provide RF signals to the RF front end 202 for amplification and / or further processing. The RF transceiver 204 can also process an RF signal provided by a low-noise amplifier of the RF front end 202. The RF transceiver 204 communicates with the processor 205. The processor 205 can be a baseband processor. The processor 205 can provide all suitable baseband processing functions for the wireless communication device 200. The processor 205 can access the memory 206. The memory 206 can store all suitable data for the wireless communication device 200.

[0083] Each of the embodiments described above can be implemented in conjunction with mobile devices such as mobile phones. The principles and advantages of the embodiments can be applied to any system or device, such as any wireless uplink communication device, that could benefit from any of the embodiments described herein. The teachings contained herein apply to a wide variety of systems. Although this disclosure includes some exemplary embodiments, the teachings described herein can be applied to a wide variety of structures. Each of the principles and advantages described herein can be implemented in conjunction with RF circuits configured to process signals in a range of approximately 30 kHz to 300 GHz, for example, in a range of approximately 450 MHz to 6 GHz.

[0084] Aspects of this disclosure may be implemented in various electronic devices. Examples of electronic devices may include, but are not limited to: consumer electronics products, components of consumer electronics products such as packaged radio frequency modules, wireless uplink communication equipment, wireless communication infrastructure, electronic test equipment, etc. Examples of electronic devices may include, but are not limited to: a mobile phone such as...A smartphone, a portable computing device such as a smartwatch or earpiece, a telephone, a television, a computer monitor, a computer, a modem, a portable computer, a laptop, a tablet computer, a microwave, a refrigerator, a vehicle electronics system such as an automotive electronics system, a stereo system, a digital music player, a radio, a camera such as a digital camera, a portable memory chip, a washing machine, a dryer, a washer-dryer, a copier, a fax machine, a scanner, a multifunctional peripheral device, a wristwatch, a watch, etc. Furthermore, electronic devices can also include unfinished products.

[0085] Unless the context clearly requires otherwise, the words "comprise," "comprehensive," "contain," "including," and the like are to be interpreted in an inclusive sense, as opposed to an exclusive or exhaustive one; that is, in the sense of "including but not limited to." The word "coupled," as used generally herein, refers to two or more elements, which may be connected either directly or through one or more intermediate elements. Likewise, the word "connected," as used generally herein, refers to two or more elements, which may be connected either directly or through one or more intermediate elements. Furthermore, the words "herein," "above," "below," and words of similar meaning, when used in this application, refer to this application as a whole and not to particular sections thereof.Where the context allows, words in the detailed description above that include singular or plural numbers can also include either the singular or plural number. The word "or" in relation to a list of two or more items covers all of the following interpretations: one of the items in the list, all of the items in the list, and any combination of the items in the list.

[0086] Furthermore, unless expressly stated otherwise or otherwise understood within the context of use, the conditional language employed herein, including but not limited to "may," "could," "might," "e.g.," "as," and the like, is generally intended to convey that certain embodiments include certain features, elements, and / or states, while other embodiments do not include certain features, elements, and / or states. Therefore, such conditional language is generally not intended to imply that features, elements, and / or states are in any way required for one or more embodiments, or that one or more embodiments necessarily include logic to decide whether such features, elements, and / or states are included or executed in a particular embodiment, with or without input or prompting from the author.

[0087] Although certain embodiments have been described, these embodiments are presented only as examples and are not intended to limit the scope of the disclosure. In fact, the novel devices, methods, and systems described herein may be embodied in a multitude of other forms; furthermore, various omissions, substitutions, and modifications to the form of the methods and systems described herein may be made without departing from the spirit of the disclosure. For example, while blocks are shown in one particular arrangement, alternative embodiments may perform similar functionalities with different components and / or circuit topologies, with some blocks being deleted, moved, added, subdivided, combined, and / or modified. Each of these blocks may be implemented in different ways.Any suitable combination of the elements and functions of the various embodiments described above can be combined to form further embodiments. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosure.

Claims

[1] Acoustic wave device (10; 20; 30; 40; 50; 60), comprising: an acoustic wave filter designed to filter a high-frequency signal; and a loop circuit coupled to the acoustic wave filter, wherein the loop circuit is configured to generate an antiphase signal to a target signal at a specific frequency, the loop circuit comprising a Lamb wave resonator (14; 34; 64; 70; 70', 70''; 70''''; 70''''; 70''''; 70''''; 70''''') which has a piezoelectric layer (15'; 15''; 15'''; 115) and an interdigital transducer electrode (16; 112; 112') arranged on the piezoelectric layer (15'; 15''; 15'''; 115), wherein the piezoelectric layer (15'; 15''; 15'''; 115) comprises free edges, one edge of the piezoelectric layer (15'; 15''; 15'''; 115) is formed with an overhang to the interdigital transducer electrode (16; 112; 112') to either suppress or scatter reflections of acoustic waves generated by the interdigital transducer electrode (16; 112; 112') from the edge of the piezoelectric layer (15; 15''; 15'''; 115). [2] Acoustic wave device (10; 20; 30; 40; 50; 60) according to claim 1, wherein the piezoelectric layer (15'; 15''; 15'''; 115) is an aluminium nitride layer, a lithium niobate layer or a lithium tantalate layer. [3] Acoustic wave device (10; 20; 30; 40; 50; 60) according to claim 1 or 2, wherein an acoustic wave mode used in the Lamb wave resonator (14; 34; 64; 70; 70', 70''; 70''''; 70''''; 70''''; 70''''; 70''''') is one of the following modes: the asymmetric (A0) lowest order mode, the symmetric (S0) lowest order mode, the horizontal shear (SH0) lowest order mode, an asymmetric (A1) first order mode, the symmetric (S1) first order mode or the horizontal shear (SH1) first order mode. [4] Acoustic wave device (30; 40; 60) according to one of claims 1 to 3, wherein the Lamb wave resonator (34; 64) is a surface-bound resonator. [5] Acoustic wave device (10; 20; 50) according to one of claims 1 to 3, wherein the Lamb wave resonator (14; 70; 70', 70'''; 70'''; 70''''; 70''''') is a freestanding resonator. [6] Acoustic wave device (10; 30; 60) according to one of claims 1 to 5, wherein the acoustic wave filter comprises a volume acoustic wave resonator (12; 62). [7] Acoustic wave device (10; 30; 60) according to claim 6, wherein the piezoelectric layer (15'; 15'''; 15''''; 115) of the Lamb wave resonator (14; 34; 64; 70; 70', 70''; 70'''; 70''''; 70''''; 70''''') is formed from the same material as a piezoelectric layer (15; 15'''') of the volume acoustic wave resonator (12; 62). [8] Acoustic wave device (10; 30; 60) according to claim 7, wherein the material comprises aluminium nitride. [9] Acoustic wave device (10; 30) according to one of claims 6 to 8, wherein the volume acoustic wave resonator is a thin-film volume acoustic wave resonator (12). [10] Acoustic wave device (60) according to one of claims 6 to 8, wherein the volume acoustic wave resonator is a surface-bound resonator (62). [11] Acoustic wave device (20; 40; 50) according to one of claims 1 to 5, wherein the acoustic wave filter comprises a second Lamb wave resonator (24; 44; 52). [12] Acoustic wave device (10; 20; 30; 40; 50; 60) according to any one of claims 1 to 11, wherein the Lamb wave resonator and at least one resonator of the acoustic wave filter are arranged on the same semiconductor substrate. [13] Acoustic wave device (10; 20; 30; 40; 50; 60) according to any one of claims 1 to 12, wherein the acoustic wave filter is a transmit filter (82). [14] Acoustic wave device (10; 20; 30; 40; 50; 60) according to any one of claims 1 to 12, wherein the acoustic wave filter is a receiving filter (84). [15] Acoustic wave device (10; 20; 30; 40; 50; 60) according to any one of claims 1 to 14, further comprising a second acoustic wave filter, wherein the acoustic wave filter and the second acoustic wave filter are contained in a duplexer (80; 100; 120). [16] Acoustic wave device (10; 20; 30; 40; 50; 60) according to any one of claims 1 to 15, wherein the edges of the piezoelectric layer (15'; 15''; 15'''; 115) have several curved sections. [17] High-frequency module (182; 184; 187), comprising: a duplexer (182) comprising an acoustic wave device, wherein the acoustic wave device comprises an acoustic wave filter configured to filter a high-frequency signal, and a loop circuit coupled to the acoustic wave filter, wherein the loop circuit is configured to generate an antiphase signal to a target signal at a specified frequency, and wherein the loop circuit comprises a Lamb wave resonator with a piezoelectric layer and an interdigital transducer electrode arranged on the piezoelectric layer, wherein the piezoelectric layer comprises free edges, one edge of the piezoelectric layer being configured with an overhang to the interdigital transducer electrode to suppress or scatter reflections of acoustic waves generated by the interdigital transducer electrode from the edge of the piezoelectric layer; and a high-frequency switch (183; 186) arranged to allow a high-frequency signal to pass through which is assigned to a port of the duplexer. [18] High-frequency module (184; 187) according to claim 17, further comprising a power amplifier (185), wherein the high-frequency switch (186) is coupled in a signal path between the power amplifier (185) and the duplexer (182). [19] High-frequency module (182; 184; 187) according to claim 17 or 18, wherein the high-frequency switch is either an antenna switch (183) or a band selector switch (186). [20] High-frequency module (182; 184; 187) according to one of claims 17 to 19, wherein the edges of the piezoelectric layer have several curved sections. [21] Wireless communication device (200), comprising: a high-frequency front end (202) comprising an acoustic wave device, wherein the acoustic wave device comprises an acoustic wave filter configured to filter a high-frequency signal, and a loop circuit coupled to the acoustic wave filter, wherein the loop circuit is configured to generate an antiphase signal to a target signal at a specified frequency, and wherein the loop circuit comprises a Lamb wave resonator with a piezoelectric layer and an interdigital transducer electrode arranged on the piezoelectric layer, wherein the piezoelectric layer comprises free edges, one edge of the piezoelectric layer being configured with an overhang to the interdigital transducer electrode to suppress or scatter reflections of acoustic waves generated by the interdigital transducer electrode from the edge of the piezoelectric layer; and an antenna (201) in communication with the high-frequency front end (202). [22] Wireless communication device (200) according to claim 21, wherein the edges of the piezoelectric layer have several curved sections. [23] Filter (82; 84), comprising: an input connector (TX; R09); an output port (T09; RX); a main volume acoustic wave filter circuit connected between the input terminal and the output terminal, wherein the main volume acoustic wave filter circuit has a first phase characteristic, a first passband and a first stopband; and a phase shift circuit (83; 103) connected in parallel to the main volume acoustic wave filter circuit between the input terminal and the output terminal, wherein the phase shift circuit (83; 103) comprises a first capacitor element (CAP01; CAP04), a second capacitor element (CAP02; CAP03) and a Lamb mode-coupled resonator (86, 87; 106, 107) connected in series between the first capacitor element and the second capacitor element, wherein the Lamb mode-coupled resonator (86, 87;106, 107) comprising at least two interdigital transducer electrodes arranged separately from one another on a piezoelectric layer in a single acoustic wave path along which acoustic waves propagate through the Lamb mode-coupled resonator, wherein the piezoelectric layer has free edges, wherein an edge of the piezoelectric layer is configured with an overhang towards the interdigital transducer electrodes such that it either suppresses or scatters reflections of acoustic waves generated by the Lamb mode-coupled resonator from the edge of the piezoelectric layer, wherein the phase-shift circuit has a second phase characteristic which is opposite to the first phase characteristic in an attenuation band corresponding to at least one section of the first stopband.; [24] Filter (82; 84) according to claim 23, wherein the edges of the piezoelectric layer have several curved sections.

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