Patent ID: 12255606

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

The following description of certain embodiments presents various descriptions of specific embodiments. However, the innovations described herein can be embodied in a multitude of different ways, for example, as defined and covered by the claims. In this description, reference is made to the drawings where like reference numerals can indicate identical or functionally similar elements. It will be understood that elements illustrated in the figures are not necessarily drawn to scale. Moreover, it will be understood that certain embodiments can include more elements than illustrated in a drawing and/or a subset of the elements illustrated in a drawing. Further, some embodiments can incorporate any suitable combination of features from two or more drawings.

An acoustic wave filter can include a loop circuit to cancel an unwanted frequency component. The loop circuit can enhance transmit/receive isolation and attenuation for a particular frequency range. The loop circuit can apply a signal having approximately the same amplitude and an opposite phase to a signal component to be canceled. Surface acoustic wave (SAW) loops circuits have been used to suppress isolation and attenuation in SAW filters. Some loop circuits for film bulk acoustic resonator (FBAR) filters and other bulk acoustic wave (BAW) filters have included LC circuits. Such LC circuits can include capacitor(s) and/or inductor(s) having a relatively large physical footprint and/or can be implemented external to a chip that includes the BAW filter coupled to the loop circuit.

Lamb wave loop circuits are disclosed. Lamb wave loop circuits can be integrated with BAW filters and/or duplexers. For instance, aluminum nitride (AlN) Lamb wave loop circuits can be integrated with aluminum nitride FBAR filters. Such Lamb wave loop circuits can suppress transmit/receive (Tx/Rx) isolation and attenuation at any desired frequency range. A Lamb wave loop circuit can generate an anti-phase radio frequency (RF) signal to cancel a target signal at a desired frequency. The Lamb wave loop circuits discussed herein can 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.

A Lamb wave element can be a Lamb wave resonator or a Lamb wave delay line. A Lamb wave element can combine features of a SAW element and a BAW element. A Lamb wave resonator typically includes an interdigital transducer (IDT) electrode similar to a SAW resonator. Accordingly, the frequency of the Lamb wave resonator can be lithographically defined. A Lamb wave element can achieve a relatively high quality factor (Q) and a relatively high phase velocity like a BAW filter. The relatively high Q of a Lamb wave resonators can be due to, for example, a suspended structure. A Lamb wave element that includes an aluminum nitride piezoelectric layer can be relatively easy to integrate with other circuits, for example, because aluminum nitride process technology can be compatible with complementary metal oxide semiconductor (CMOS) process technology. Aluminum nitride Lamb wave resonators can overcome a relatively low resonance frequency limitation and integration challenge associated with SAW resonators and also overcome multiple frequency capability challenges associated with BAW resonators. Some Lamb wave resonator topologies are based on acoustic reflection from periodic reflective gratings. Some other Lamb wave resonator topologies are based on acoustic reflection from suspended free edges of a piezoelectric layer.

A Lamb wave loop circuit and a BAW resonator of an acoustic wave filter can be implemented on a common substrate. An aluminum nitride Lamb wave loop circuit can be directly integrated with aluminum nitride FBAR filter and/or other BAW filters during processing to form such filters. Such integration can also be achieved for other suitable piezoelectric films. Accordingly, a Lamb wave loop circuit can have offer a cost effective and efficient way to include a loop circuit for a BAW filter. A Lamb wave loop circuit integrated with a BAW filter can be manufactured with characteristics sufficient for a loop circuit in a cost effective manner. A Lamb wave loop circuit for a BAW filter can be implemented in a relatively small physical footprint. For example, a Lamb wave loop circuit can have a smaller physical footprint than an LC circuit based loop circuit. A smaller physical footprint can reduce power consumption and/or reduce manufacturing costs.

Lamb wave elements in a loop circuit discussed herein can operate in any suitable acoustic wave mode. Example acoustic wave modes that can be utilized in Lamb wave elements discussed herein include the lowest-order asymmetric (A0) mode, the lowest-order symmetric (S0) mode, the lowest-order shear horizontal (SH0) mode, the first-order asymmetric (A1) mode, the first-order symmetric (S1) mode, the first-order shear horizontal (SH1) mode, the second-order asymmetric (A2) mode, the second-order symmetric (S2) mode, the second-order shear horizontal (SH2) mode, and the like.

A Lamb wave element and a different type of acoustic wave resonator can be implemented on the same substrate of a die. The Lamb wave element can be included in a loop circuit and the different element can be in an acoustic wave filter coupled to the loop circuit. A Lamb wave element and a different type of acoustic wave element on a common substrate can be implemented in a variety of other applications. In certain instances, an acoustic wave filter can include a Lamb wave resonator and a different type of acoustic wave resonator implemented on the same die. For example, an acoustic wave filter can include a Lamb wave resonator and an FBAR implemented on a common substrate. According to certain applications, a first acoustic wave filter can include a Lamb wave resonator and a second acoustic wave filter can include a different type of acoustic wave resonator, in which the Lamb wave resonator and the different type of acoustic wave resonator are implemented on a common substrate.

A loop circuit can include a free-standing Lamb wave element. For example, such a Lamb wave element and a resonator of an acoustic wave filter coupled to the loop circuit can be implemented in accordance with any suitable principles and advantages of the acoustic wave devices ofFIGS.1A to5D. The acoustic wave devices ofFIGS.1A to5Dcan also be implemented in other applications. Any suitable combination of features of the acoustic wave devices ofFIGS.1A to5Dcan be implemented together with each other.

FIG.1Ais a diagram of cross section of an acoustic wave device10that includes a film bulk acoustic resonator (FBAR)12and a Lamb wave element14according to an embodiment. The FBAR12and the Lamb wave element14are implemented on a common substrate19. The FBAR12can be included in an acoustic wave filter and the Lamb wave element14can be included in a loop circuit. The FBAR12includes electrodes13A and13B on opposing sides of a piezoelectric substrate15. The Lamb wave element14can be a Lamb wave resonator in certain instances. A Lamb wave resonator is a type of acoustic wave resonator. The Lamb wave element14can be a delay line in some instances. A Lamb wave delay line can include two sets of interdigital transducers.

The Lamb wave element14includes feature of a SAW resonator and an FBAR. As illustrated, the Lamb wave element14includes a piezoelectric layer15, an interdigital transducer electrode (IDT) electrode16on the piezoelectric layer15, and an electrode17. The piezoelectric layer15can be a thin film. The piezoelectric layer15can be an aluminum nitride layer. In other instances, the piezoelectric layer15can be any suitable piezoelectric layer. For example, the piezoelectric layer15can be a lithium niobate layer or a lithium tantalate layer. The frequency of the Lamb wave resonator can be based on the geometry of the IDT electrode16. In some instances, the illustrated IDTs of the Lamb wave element14represent two sets of IDTs. The electrode17can be grounded in certain instances. In some other instances, the electrode17can be floating. An air cavity18is disposed between the electrode17and a substrate19. Any suitable cavity can be implemented in place of the air cavity18. The substrate19can be a semiconductor substrate. For example, the substrate19can be a silicon substrate. The substrate19can be any other suitable substrate, such as a quartz substrate, a sapphire substrate, or a spinel substrate.

In the acoustic wave device10, the Lamb wave resonator14and the FBAR12share a piezoelectric layer15. A first portion of the piezoelectric layer15can be considered the piezoelectric layer of the FBAR12and a second portion of the piezoelectric layer15can be considered the piezoelectric layer of the Lamb wave element14. As also illustrated inFIG.1A, the Lamb wave resonator14and the FBAR share an air cavity18. In certain applications, sharing an air cavity18can reduce the size of an acoustic wave device relative to implementing separate air cavities. The Lamb wave resonator14and the FBAR12can be disposed on a common semiconductor substrate19. The semiconductor substrate19can be a silicon substrate.

FIG.1Bis a diagram of cross section of an acoustic wave device10′ that includes an FBAR12′ and a Lamb wave element14′ according to an embodiment. The acoustic wave device10′ is like the acoustic wave device10ofFIG.1Aexcept that separate air cavities18A and18B are included in the acoustic wave device10′ for the FBAR12′ and the Lamb wave element14′, respectively. In the acoustic wave device10′, a first air cavity18A is provided for the FBAR12′ and a second air cavity18B is provided for the Lamb wave element14′. In certain instances, having separate air cavities can be beneficial for maintaining the mechanical integrity of the acoustic wave device10′ and/or reducing cross talk between the FBAR12and the Lamb wave element14.

FIG.1Cis a diagram of cross section of an acoustic wave device10″ that includes an FBAR12″ and a Lamb wave element14″ according to an embodiment. The acoustic wave device10″ is like the acoustic wave device10ofFIG.1Aexcept that an air cavity is implemented in the substrate19′ instead of over the substrate19ofFIG.1A. An air cavity18′ can be implemented for the acoustic wave device10″ by etching a portion of the substrate19′.

FIG.1Dis a diagram of cross section of an acoustic wave device10′″ that includes an FBAR12′″ and a Lamb wave element14′″ according to an embodiment. The acoustic wave device10′″ is like the acoustic wave device10′ ofFIG.1Bexcept that air cavities are implemented in the substrate19″ instead of over the substrate19ofFIG.1B. The air cavities18A′ and18B′ can be implemented for the acoustic wave device10′″ by etching portions of the substrate19″.

FIG.2is a diagram of cross section of an acoustic wave device20that includes a Lamb wave element14and a solidly mounted resonator (SMR)22according to an embodiment. In the acoustic wave device20, the SMR22and the Lamb wave element14are implemented on a common substrate19. The SMR22can be included in an acoustic wave filter and the Lamb wave element14can be included in a loop circuit. The SMR22and the Lamb wave element14can include the same piezoelectric material, such as aluminum nitride (AlN). A piezoelectric layer15′ of the acoustic wave device20can include a first portion that serves as a piezoelectric layer for the Lamb wave element14and a second portion that serves as a piezoelectric layer for the SMR22. The piezoelectric layer15′ can have a different shape than the piezoelectric layer15in the acoustic wave device10ofFIG.1A.

The SMR22includes an acoustic mirror located between the substrate19and the electrode13B. The illustrated acoustic mirror includes Bragg reflectors24. As illustrated, the Bragg reflectors24include alternating low impedance and high impedance layers25and26, respectively. As an example, the Bragg reflectors24can include silicon dioxide (SiO2) layers and tungsten (W) layers. As another example, the Bragg reflectors24can include silicon dioxide layers and molybdenum (Mo) layers. Any other suitable Bragg reflectors can alternatively or additionally be included in the SMR22. The Lamb wave element14ofFIG.2includes its own an air cavity18B. The Lamb wave element14and the SMR22can be disposed on a common substrate19. The substrate19can be a semiconductor substrate. For example, the substrate19can be a silicon substrate. The substrate19can be any other suitable substrate disclosed herein.

FIG.3Ais a diagram of cross section of an acoustic wave device30that includes a Lamb wave element14and a surface acoustic wave (SAW) resonator32according to an embodiment. In the acoustic wave device30, the SAW resonator32and the Lamb wave element14are implemented on a common substrate19. The SAW resonator32can be included an acoustic wave filter and the Lamb wave element can be included in a loop circuit. The SAW resonator32can include any suitable piezoelectric layer, such as an aluminum nitride layer, a lithium niobate layer, a lithium tantalate layer, or any suitable combination thereof. The SAW resonator32and the Lamb wave element14can include the same piezoelectric material, such as aluminum nitride, lithium niobate or lithium tantalate. A piezoelectric layer15″ of the acoustic wave device30can include a first portion that serves as a piezoelectric layer for the Lamb wave element14and a second portion that serves as a piezoelectric layer for the SAW resonator32. The SAW resonator32includes an IDT electrode34on the piezoelectric layer15′. The piezoelectric layer15″ can have a different shape than the piezoelectric layer15in the acoustic wave device10ofFIG.1A. The Lamb wave element14and the SAW32can be disposed on a common substrate19. The substrate19can be a semiconductor substrate, such as a silicon substrate.

FIG.3Bis a diagram of cross section of an acoustic wave device30′ that includes a Lamb wave element14and an SAW resonator32′ according to an embodiment. The acoustic wave device30′ is like the acoustic wave device30ofFIG.3Aexcept that the respective piezoelectric layers15″ and35of the Lamb wave element14and the SAW resonator32′ include different piezoelectric material. For example, the SAW resonator32′ can include a lithium niobate piezoelectric layer35and the Lamb wave element14can include a lithium niobate piezoelectric layer15″. As another example, the SAW resonator32′ can include a lithium tantalate piezoelectric layer35and the Lamb wave element14can include a lithium tantalate piezoelectric layer15″.

Although the acoustic wave devices30and30′ are illustrated with a Lamb wave element that includes a cavity18B over the substrate19, similar acoustic wave devices can be implemented with a cavity in the substrate (e.g., like the cavity18B′ ofFIG.1B).

FIG.4Ais a diagram of cross section of an acoustic wave device40that includes a Lamb wave element14and a Lamb wave resonator42according to an embodiment. In the acoustic wave device40, the Lamb wave resonator42and the Lamb wave element14are implemented on a common substrate19. The Lamb wave resonator42can be included in an acoustic wave filter and the Lamb wave element14can be included in a loop circuit. The Lamb wave resonator42can have the same or similar structure as the Lamb wave element14. In some instances, the Lamb wave element14can include two sets of IDTs and the Lamb wave resonator42can include a single set of IDTs. The Lamb wave element14and The Lamb wave resonator42can share a piezoelectric layer15. As shown inFIG.4A, the Lamb wave element14and The Lamb wave resonator42can share an air cavity18. In certain applications, sharing an air cavity18can reduce the size of an acoustic wave device relative to implementing separate air cavities.

FIG.4Bis a diagram of cross section of an acoustic wave device40′ that includes a Lamb wave element14and a Lamb wave resonator42according to an embodiment. The acoustic wave device40′ is like the acoustic wave device40ofFIG.4Aexcept that separate air cavities18A and18B are included in the acoustic wave device40′ for the Lamb wave resonator42and the Lamb wave element14, respectively. In the acoustic wave device40′, a first air cavity18A is provided for the Lamb wave resonator42and a second air cavity18B is provided for the Lamb wave element14. In certain instances, having separate air cavities can be beneficial for maintaining the mechanical integrity of the acoustic wave device40′ and/or reducing cross talk between the Lamb wave resonator42and the Lamb wave element14.

FIG.5Ais a diagram of cross section of an acoustic wave device50that includes a Lamb wave element14and a solidly mounted Lamb wave resonator52according to an embodiment. In the acoustic wave device50, the solidly mounted Lamb wave resonator52and the Lamb wave element14are implemented on a common substrate19. The solidly mounted Lamb wave resonator52can be included in an acoustic wave filter and the Lamb wave element14can be included in a loop circuit. The solidly mounted Lamb wave resonator52and the Lamb wave element14can include the same piezoelectric material, such as aluminum nitride. A piezoelectric layer15′ of the acoustic wave device50can include a first portion that serves as a piezoelectric layer for the Lamb wave element14and a second portion that serves as a piezoelectric layer for the solidly mounted Lamb wave resonator52.

The solidly mounted Lamb wave resonator52includes features of a SAW resonator and an SMR. The solidly mounted Lamb wave resonator52includes a lower electrode53, a piezoelectric layer, an IDT electrode54on the piezoelectric layer, and an acoustic mirror located between the substrate19and the electrode53. The illustrated acoustic mirror includes Bragg reflectors56. As illustrated, the Bragg reflectors56include alternating low impedance and high impedance layers57and58, respectively. As an example, the Bragg reflectors56can include silicon dioxide layers and tungsten layers. Any other suitable Bragg reflectors can alternatively or additionally be included in the solidly mounted Lamb wave resonator52. The solidly mounted Lamb wave resonator52can include an aluminum nitride piezoelectric layer, for example.

FIG.5Bis a diagram of cross section of an acoustic wave device50′ that includes a Lamb wave element14and solidly mounted Lamb wave resonator52according to an embodiment. The acoustic wave device50′ is like the acoustic wave device50ofFIG.5Aexcept that the respective piezoelectric layers15′ and59of the Lamb wave element14and the solidly mounted Lamb wave resonator52include different piezoelectric material.

FIG.5Cis a diagram of cross section of an acoustic wave device50″ that includes a Lamb wave element14and solidly mounted Lamb wave resonator52according to an embodiment. The acoustic wave device50″ is like the acoustic wave device50ofFIG.5Aexcept that an air cavity18B′ is implemented in the substrate19instead of over the substrate19ofFIG.5A. The air cavity18B′ can be implemented for the acoustic wave device50″ by etching a portion of the substrate19′.

FIG.5Dis a diagram of cross section of an acoustic wave device50′ that includes a Lamb wave element14and solidly mounted Lamb wave resonator52according to an embodiment. The acoustic wave device50′ is like the acoustic wave device50″ ofFIG.5Cexcept that the respective piezoelectric layers15′ and59of the Lamb wave element14and the solidly mounted Lamb wave resonator52include different piezoelectric material.

A loop circuit can include a solidly mounted Lamb wave element. For example, such a Lamb wave element and a resonator of an acoustic wave filter coupled to the loop circuit can be implemented in accordance with any suitable principles and advantages of the acoustic wave devices ofFIGS.6to10. The acoustic wave devices ofFIGS.6to10can also be implemented in other applications. Any suitable combination of features of acoustic wave devices ofFIGS.6to10can be implemented together with each other.

FIG.6is a diagram of cross section of an acoustic wave device60that includes a solidly mounted Lamb wave element64and an FBAR12′ according to an embodiment. The FBAR12′ and the solidly mounted Lamb wave element64are implemented on a common substrate19. The FBAR12′ can be included in an acoustic wave filter and the solidly mounted Lamb wave element64can be included in a loop circuit. The solidly mounted Lamb wave element64can be a solidly mounted Lamb wave resonator in certain instances. The solidly mounted Lamb wave element64can be a delay line in some instances. A Lamb wave delay line can include two sets of interdigital transducers.

The Lamb wave element64includes feature of a SAW resonator and an SMR. As illustrated, the Lamb wave element64includes a piezoelectric layer15′″, an IDT electrode16on the piezoelectric layer15′″, and an electrode17. The piezoelectric layer15′″ can be an aluminum nitride layer. In other instances, the piezoelectric layer15′″ can be any other suitable piezoelectric layer. The frequency of the Lamb wave element64can be based on the geometry of the IDT electrode16. The electrode17can be grounded in certain instances. In some other instances, the electrode17can be floating. The Lamb wave element64includes an acoustic mirror located between the substrate19and the electrode17. The illustrated acoustic mirror includes Bragg reflectors65. As illustrated, the Bragg reflectors65include alternating low impedance and high impedance layers66and67, respectively. As an example, the Bragg reflectors65can include silicon dioxide layers and tungsten layers. As another example, the Bragg reflectors65can include silicon dioxide layers and molybdenum layers. Any other suitable Bragg reflectors can alternatively or additionally be included in the Lamb wave element64.

In the acoustic wave device60, the Lamb wave element64and the FBAR12′ can share a piezoelectric layer15′″. In some other embodiments, the Lamb wave element64and the FBAR12′ can include piezoelectric layers of different material. The piezoelectric layer15′″ can have a different shape than piezoelectric layers in other embodiments that have different resonator combinations. The Lamb wave element64and the FBAR12′ can be disposed on a common substrate19. The substrate19can be a semiconductor substrate. For example, the substrate19can be a semiconductor substrate. The substrate19can be any other suitable substrate, such as a quartz substrate, a sapphire substrate, or a spinel substrate.

FIG.7is a diagram of cross section of an acoustic wave device70that includes a solidly mounted Lamb wave element64and an SMR22according to an embodiment. In the acoustic wave device70, the SMR22and the Lamb wave element64are implemented on a common substrate19. The SMR22can be included in an acoustic wave filter and the Lamb wave element64can be included in a loop circuit. The solidly mounted Lamb wave element64is structurally similar to the SMR22, except that the solidly mounted Lamb wave element64includes an IDT electrode16and the SMR22includes an electrode13A having a different shape than the IDT electrode16over the piezoelectric layer15′. The Bragg reflectors65for the solidly mounted Lamb wave element64and the Bragg reflectors24for the SMR22can be separated by material of the substrate19. For instance, semiconductor material of a semiconductor substrate19can separate Bragg reflectors24from Bragg reflectors65. The Bragg reflectors65and24can include the same materials in certain applications. The Bragg reflectors65and24can include different materials in certain applications. In some applications, Bragg reflectors can form a common acoustic mirror below the Lamb wave element64and the SMR22. The piezoelectric layers15′″ and68of the solidly mounted Lamb wave element64and the SMR22, respectively, can include the same piezoelectric material in certain applications. The piezoelectric layers15′″ and68of the solidly mounted Lamb wave element64and the SMR22, respectively, can include different piezoelectric material in various applications.

FIG.8is a diagram of cross section of an acoustic wave device80that includes a solidly mounted Lamb wave element64and a SAW resonator32according to an embodiment. The solidly mounted Lamb wave element64and the SAW resonator32can be on a common substrate19. The SAW resonator32can be included in an acoustic wave filter and the Lamb wave element64can be included in a loop circuit. The piezoelectric layers15″″ and35of the solidly mounted Lamb wave element64and the SAW resonator32, respectively, can include the same piezoelectric material in certain applications. The piezoelectric layers15″″ and35of the solidly mounted Lamb wave element64and the SAW resonator32, respectively, can include different piezoelectric material in various applications.

FIG.9is a diagram of cross section of an acoustic wave device90that includes a solidly mounted Lamb wave element64of and a Lamb wave resonator42′ according to an embodiment. The Lamb wave resonator42′ is a free-standing Lamb wave resonator. The solidly mounted Lamb wave element64and the Lamb wave resonator42′ can include the same piezoelectric material, such as aluminum nitride, lithium niobate, or lithium tantalate. In some other applications, the solidly mounted Lamb wave element64and the Lamb wave resonator42′ can include piezoelectric layers of different material. The solidly mounted Lamb wave element64and the Lamb wave resonator42′ can be disposed on a common substrate19. The Lamb wave resonator42′ can be included in an acoustic wave filter and the Lamb wave element64can be included in a loop circuit.

FIG.10is a diagram of cross section of an acoustic wave device100that includes a solidly mounted Lamb wave element64and a solidly mounted Lamb wave resonator52according to an embodiment. These solidly mounted Lamb wave elements can be structurally similar or the same. In the acoustic wave device100, the solidly mounted Lamb wave resonator52and the Lamb wave element64are implemented on a common substrate19. The solidly mounted Lamb wave resonator52can be included in an acoustic wave filter and the Lamb wave element64can be included in a loop circuit. Semiconductor material of the semiconductor substrate19can separate Bragg reflectors of these solidly mounted Lamb wave elements. The Bragg reflectors65and56can include the same materials in certain applications. The Bragg reflectors65and56can include different materials in certain applications. In some applications, Bragg reflectors can form a common acoustic mirror below the Lamb wave element64and the solidly mounted Lamb wave resonator52. The piezoelectric layers15′″ and59of the solidly mounted Lamb wave element64and the solidly mounted Lamb wave resonator52, respectively, can include the same piezoelectric material in certain applications. The piezoelectric layers15′″ and68of the solidly mounted Lamb wave element64and the solidly mounted Lamb wave resonator52, respectively, can include different piezoelectric material in various applications.

Lamb wave elements can include an IDT electrode on a piezoelectric layer and reflective gratings disposed on the piezoelectric layer on opposing sides of the IDT electrode. The reflective gratings can reflect acoustic waves induced by the IDT electrode to form a resonant cavity. The reflective gratings can include a periodic pattern of metal on a piezoelectric layer.FIGS.11A to11Fare diagrams of cross sections of Lamb wave elements with gratings. A Lamb wave element in a loop circuit can be implemented with any suitable principles and advantages of any of the Lamb wave elements ofFIGS.11A to11F. A Lamb wave resonator in a filter can be implemented with any suitable principles and advantages of any of the Lamb wave elements ofFIGS.11A to11F. Although the Lamb wave elements ofFIGS.11A to11Fare free-standing resonators, any suitable principles and advantages of these Lamb wave resonators can be applied to any other suitable Lamb wave elements.

FIG.11Aillustrates a Lamb wave element110that includes an IDT electrode112, gratings113and114, a piezoelectric layer115, and an electrode116. The IDT electrode112is on the piezoelectric layer115. In the illustrated cross section, alternate ground and signal metals are included in the IDT electrodes. Gratings113and115are on the piezoelectric layer115and disposed on opposing sides of the IDT electrodes112. The illustrated gratings113and115are shown as being connected to ground. Alternatively, one or more of the gratings can be signaled and/or floating. The electrode116and the IDT electrode112are on opposite sides of the piezoelectric layer115. The piezoelectric layer115can be aluminum nitride, for example. The electrode116can be grounded.

FIG.11Billustrates a Lamb wave element110′. The Lamb wave element110′ is like the Lamb wave element110ofFIG.11Aexcept that the Lamb wave element110′ includes a floating electrode116′.

FIG.11Cillustrates a Lamb wave element110″ without an electrode on a side of the piezoelectric layer115that opposes the IDT electrode112. The Lamb wave element110″ is otherwise like the Lamb wave element110ofFIG.11A.

FIG.11Dillustrates a Lamb wave element110′″ that includes an IDT electrode117and gratings118and119on a second side of the piezoelectric layer115that is opposite to a first side on which the IDT electrode112and gratings113and114are disposed. The signal and ground electrodes are offset relative to each other for the IDT electrodes112and117.

FIG.11Eillustrates a Lamb wave element110″ that includes an IDT electrode117′ and gratings118and119on a second side of the piezoelectric layer115that is opposite to a first side on which the IDT electrode112and gratings113and114are disposed. The signal and ground electrodes are aligned with each other for the IDT electrodes112and117′.

FIG.11Fillustrates a Lamb wave element110′″″ that includes an IDT electrode117″ and gratings118and119on a second side of the piezoelectric layer115that is opposite to a first side on which the IDT electrode112′ and gratings113and114are disposed. In the illustrated cross section, the IDT112′ includes only signal electrodes and the IDT electrode117″ includes only ground electrodes.

Lamb wave elements can include an IDT electrode with free edges. Suspended free edges of a piezoelectric layer can provide acoustic wave reflection to form a resonant cavity.FIGS.12A to12Fare diagrams of cross sections of Lamb wave elements with free edges. A Lamb wave element in a loop circuit can be implemented with any suitable principles and advantages of any of the Lamb wave elements ofFIGS.12A to12F. A Lamb wave resonator in a filter can be implemented with any suitable principles and advantages of any of the Lamb wave elements ofFIGS.12A to12F. Although the Lamb wave elements ofFIGS.12A to12Fare free-standing elements, any suitable principles and advantages of these Lamb wave elements can be applied to other Lamb wave elements.

FIG.12Aillustrates a Lamb wave element120that includes IDT electrode112, piezoelectric layer115, and an electrode116. The IDT electrode112is on the piezoelectric layer115. In the illustrated cross section, alternate ground and signal electrodes are included in the IDT electrodes. The piezoelectric layer115has free edges on opposing sides of the IDT electrode112. The electrode116and the IDT electrode112are on opposite sides of the piezoelectric layer115. The piezoelectric layer115can be aluminum nitride, for example. The electrode116can be grounded.

FIG.12Billustrates a Lamb wave element120′. The Lamb wave element120′ is like the Lamb wave element120ofFIG.12Aexcept that the Lamb wave element120′ includes a floating electrode116′.

FIG.12Cillustrates a Lamb wave element120″ without an electrode on a side of the piezoelectric layer115that opposes the IDT electrode112. The Lamb wave element120″ is otherwise like the Lamb wave element120ofFIG.12A.

FIG.12Dillustrates a Lamb wave element120′″ that includes an IDT electrode117on a second side of the piezoelectric layer115that is opposite to a first side on which the IDT electrode112is disposed. The signal and ground electrodes are offset relative to each other for the IDT electrodes112and117.

FIG.12Eillustrates a Lamb wave element120″ that includes an IDT electrode117′ on a second side of the piezoelectric layer115that is opposite to a first side on which the IDT electrode112is disposed. The signal and ground electrodes are aligned with each other for the IDT electrodes112and117′.

FIG.12Fillustrates a Lamb wave element120′″″ that includes an IDT electrode117′ on a second side of the piezoelectric layer115that is opposite to a first side on which the IDT electrode112′ is disposed. In the illustrated cross section, the IDT electrode112′ includes only signal electrodes and the IDT electrode117″ includes only ground electrodes.

The Lamb wave loop circuits discussed herein can be coupled to an acoustic wave filter. For instance, a Lamb wave element can be coupled to an acoustic wave filter of a duplexer or other multiplexer (e.g., a quadplexer, hexaplexer, octoplexer, etc.).FIGS.13,15,17, and19are schematic diagrams that illustrate example duplexers that include a Lamb wave loop circuit coupled to an acoustic wave filter. Any suitable principles and advantages discussed with reference to and/or illustrated inFIGS.1A to12Fcan be applied to any of the example duplexers ofFIGS.13,15,17, and19. Any suitable principles and advantages of the embodiments ofFIGS.13,15,17, and19can be implemented together with each other.

FIG.13is a schematic diagram of a duplexer130with a loop circuit133for a transmit filter132. The duplexer130includes a transmit filter132, a receive filter134, and a loop circuit133. The transmit filter132and the receive filter134are coupled together at a common node, which is an antenna node inFIG.13. An antenna135is coupled to the common node of the duplexer130. A shunt inductor L1can be coupled between the antenna135and ground.

The transmit filter132can filter an RF signal received at the transmit port TX for transmission via the antenna135. A series inductor L2can be coupled between the transmit port TX and acoustic wave resonators of the transmit filter132. The transmit filter132is an acoustic wave filter that includes acoustic wave resonators arranged as a ladder filter. The transmit filter132includes series resonators T01, T03, T05, T07, T09and shunt resonators T02, T04, T06, T08. The transmit filter132can include any suitable number of series resonators and any suitable number of shunt resonators. The acoustic wave resonators of the transmit filter132can include BAW resonators, such as FBARs and/or SMRs. In some instances, the acoustic wave resonators of the transmit filter132can include SAW resonators or Lamb wave resonators. In certain applications, the resonators of the transmit filter132can include two or more types of resonators (e.g., one or more SAW resonators and one or more BAW resonators).

A loop circuit133is coupled to the transmit filter132. The loop circuit133can be coupled to an input resonator T01and an output resonator T09of the transmit filter. In some other instances, the loop circuit133can be coupled to a different node of the ladder circuit than illustrated. The loop circuit133can apply a signal having approximately the same amplitude and an opposite phase to a signal component to be canceled. The loop circuit133includes Lamb wave elements136and137coupled to the transmit filter132by capacitors CAP02and CAP01, respectively. The Lamb wave elements136and137can together correspond to any suitable Lamb wave element disclosed herein. For example, the Lamb wave elements136and137can together correspond to the Lamb wave element14ofFIG.1A, in which each Lamb wave element136and137corresponds to a different IDT electrode of the Lamb wave element14. In this example, the transmit filter132can include an FBAR implemented on the same substrate of a die as the Lamb wave element14. The capacitors CAP01and CAP02are example attenuation elements that can coupled the transmit filter132to the loop circuit133. In various applications, an attenuation element can include a resistor, an inductor, a capacitor, or any suitable combination thereof. Any suitable principles and advantages of the Lamb wave elements of a loop circuit discussed herein can be implemented in the loop circuit133. The loop circuit133can be implemented in accordance with any suitable principles and advantages described in U.S. Pat. No. 9,246,533 and/or 9,520,857, the disclosures of these patents are hereby incorporated by reference in their entireties herein.

The receive filter134can filter a received RF signal received by the antenna135and provide a filtered RF signal to a receive port RX. The receive filter134is an acoustic wave filter that includes acoustic wave resonators arranged as a ladder filter. The receive filter134includes series resonators R01, R03, R05, R07, R09and shunt resonators R02, R04, R06, R08. The receive filter134can include any suitable number of series resonators and any suitable number of shunt resonators. The acoustic wave resonators of the receive filter134can include BAW resonators, such as FBARs and/or SMRs. In some instances, the acoustic wave resonators of the receive filter134can include SAW resonators or Lamb wave resonators. In certain applications, the resonators of the receive filter134can include two or more types of resonators (e.g., one or more SAW resonators and one or more BAW resonators). A series inductor L3can be coupled between the acoustic wave resonators of the receive filter134and the receive port RX.

FIG.14is a graph comparing isolation for the duplexer130ofFIG.13to a corresponding duplexer without a loop circuit. The acoustic wave properties of the lowest-order symmetric (S0) Lamb wave mode for a Lamb wave resonator with an aluminum nitride piezoelectric layer were used to study the loop circuits for BAW filters. The Lamb wave S0mode for such a resonator in the simulations was assumed to have a velocity of ˜9000 m/s and a K2of ˜2%. A Band 7 BAW duplexer was used in the simulations. The graph inFIG.14indicates that the loop circuit133improves receive isolation. The improvement can be about 5 decibels (dB) in certain instances as indicated byFIG.14.

FIG.15is a schematic diagram of a duplexer150with a loop circuit for a receive filter134. The duplexer150is like the duplexer130ofFIG.13, except that the duplexer150includes a loop circuit153for the receive filter134. A loop circuit153is coupled to the receive filter134. The loop circuit153can be coupled to an input resonator R09and an output resonator R01of the receive filter134. In some other instances, the loop circuit153can be coupled to a different node of the ladder circuit of the receive filter134than illustrated. The loop circuit153includes Lamb wave elements156and157coupled to the receive filter134by capacitors CAP04and CAP03, respectively. Any suitable principles and advantages of the Lamb wave elements of a loop circuit discussed herein can be implemented in the loop circuit153. For example, the Lamb wave elements156and157can together correspond to the Lamb wave element14ofFIG.14A.

FIG.16Ais a graph comparing isolation for the duplexer150ofFIG.15to a corresponding duplexer without a loop circuit. The same simulation assumptions were used to generate the graphs ofFIG.16AandFIG.16Bas for generating the graph ofFIG.14. The graph ofFIG.16Aindicates that the loop circuit153improves transmit isolation.

FIG.16Bis a graph comparing receive band rejection for the duplexer150ofFIG.15to a corresponding duplexer without a loop circuit. This graph illustrates that the loop circuit153can suppress rejection at a lower frequency range for the receive band.

FIG.17is a schematic diagram of a duplexer170with a first loop circuit133for a transmit filter132and a second loop circuit153for a receive filter134.FIG.17illustrates 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 the parameter of the acoustic wave filter within a specification. For example, a loop circuit can be implemented to bring isolation of an acoustic wave filter to be less than −60 dB to meet a specification for isolation if the acoustic wave filter would not otherwise meet the specification for isolation.

FIG.18is a graph comparing isolation for the duplexer170ofFIG.17to a corresponding duplexer without loop circuits. This graph indicates that the loop circuits133and153of the duplexer170improve both transmit and receive isolation.

FIG.19is a schematic diagram of a duplexer190with a loop circuit193. The duplexer190is like the duplexer130ofFIG.13, except that the duplexer190includes a loop circuit193that is coupled across the transmit filter132and the receive filter134. The loop circuit193is coupled to the receive port RX and the transmit port TX. In some other instances, the loop circuit193can be coupled to a different node of the ladder circuit of the receive filter134and/or a different node of the transmit filter132than illustrated. The loop circuit193includes Lamb wave elements196and197. The Lamb wave element196is coupled to the transmit filter by capacitor CAP01. The Lamb wave element197is coupled to the receive filter134by capacitor C02. Any other suitable attenuation element, such as a resistor or an inductor, can be implemented in place of or in addition to the capacitor C01and/or the capacitor C02. Any suitable principles and advantages of the Lamb wave elements of a loop circuit discussed herein can be implemented in the loop circuit193. For example, the Lamb wave elements196and197can together correspond to the Lamb wave element14ofFIG.14A.

Acoustic wave devices disclosed herein can be implemented in acoustic wave filters. Such acoustic wave filters can be band pass filters arranged to filter radio frequency signals including radio frequency signals at up to and including millimeter wave frequencies. In certain applications, an acoustic wave filter assembly can include a first filter that includes a Lamb wave resonator and a second filter that includes a different type of resonator, such as an FBAR. The first filter and the second filter can be included on a single die. A schematic diagram of an example acoustic wave filter assembly will be discussed with reference toFIG.20. Although an acoustic wave filter assembly with two filters will be described for illustrative purposes, any suitable principles and advantages can be applied to acoustic wave filter assemblies with more than two filters.

FIG.20is a schematic diagram of an acoustic wave filter assembly200that includes a first filter202with a Lamb wave resonator and a second filter204with a different type of acoustic wave resonator, in which the Lamb wave resonator and the different type of resonator are implemented on the same substrate according to an embodiment. The acoustic wave filter assembly200can include any of the acoustic wave devices ofFIGS.1A to10.

The first filter202includes Lamb wave resonators L01, L02, L03, L04, L05, L06, L07, L08, and L09arranged as a ladder filter between an RF port RF1and an antenna port ANT. The RF port RF1can be a transmit port or a receive port. The first filter202is a band pass filter having a first pass band and arranged to filter a first RF signal.

The second filter204includes acoustic wave resonators B01, B02, B03, B04, B05, B06, B07, B08, and B09arranged as a ladder filter between an RF port RF2and an antenna port ANT. The RF port RF2can be a transmit port or a receive port. The second filter204is a band pass filter having a second pass band and arranged to filter a second RF signal. The acoustic wave resonators B01to B09of the second filter204are a different type of acoustic wave resonators than the Lamb wave resonators L01to L09of the first filter202. For example, the acoustic wave resonators B01to B09of the second filter204can be BAW resonators, such as FBARs.

Some or all of the Lamb wave resonators L01to L09of the first filter202can be implemented on the same substrate of die as some or all of the acoustic wave resonators B01to B09of the second filter204. In certain instances, one or more resonators of the Lamb wave resonators L01to L09include a piezoelectric layer that includes the same material (e.g., aluminum nitride) as the piezoelectric layer of one or more of the acoustic wave resonators B01to B09. In some applications, a multiplexer (e.g., a duplexer) can include the first filter202and the second filter204coupled together at a common node (e.g., the antenna node ANT).

Acoustic wave devices disclosed herein can be implemented in an acoustic wave filter that includes a Lamb wave resonator and a different type of acoustic wave resonator. Such an acoustic wave filter can include any suitable acoustic wave device disclosed herein. The acoustic wave filter can be band pass filters arranged to filter radio frequency signals. The Lamb wave resonator and the different type of acoustic wave resonator can be implemented on the same substrate of a die. The substrate can be a silicon substrate, for example. In some instances, the different type of acoustic wave resonator can be an FBAR. The different type of acoustic wave resonator and the Lamb wave resonator can include respective piezoelectric layer of the same piezoelectric material (for example, aluminum nitride) in certain applications. Example acoustic wave filters with a Lamb wave resonator and another type of acoustic wave resonator will be discussed with reference toFIGS.21A to21F. These example acoustic wave filters can achieve desirable performance and/or loading characteristics for certain applications. Any suitable principles and advantages of these acoustic wave filters can be implemented together with each other. Moreover, any of the example acoustic wave filters ofFIGS.21A to21Fcan include an acoustic wave device in accordance with any suitable principles and advantages ofFIGS.1A to10.

FIG.21Ais a schematic diagram of an acoustic wave filter210that includes series Lamb wave resonators and other shunt acoustic wave resonators according to an embodiment. The series Lamb wave resonators LS01, LS02, LS03, LS04, and LS05and other shunt acoustic wave resonators BP01, BP02, BP03, BP04, and BP05are arranged as a ladder filter coupled between an RF port RF and an antenna port ANT. The RF port RF can be a transmit port of a transmit filter. The RF port can be a receive port of a receive filter. Any suitable number of series resonators and any suitable number of shunt resonators can be included in the acoustic wave filter210. The other shunt acoustic wave resonators BP01, BP02, BP03, BP04, and BP05can be FBARs. In some other instances, the other shunt acoustic wave BP01, BP02, BP03, BP04, and BP05can be SAW resonators or SMRs.

FIG.21Bis a schematic diagram of an acoustic wave filter212that includes shunt Lamb wave resonators and other series acoustic wave resonators according to an embodiment. The shunt Lamb wave resonators LP01, LP02, LP03, LP04, and LP05and other series acoustic wave resonators BS01, BS02, BS03, BS04, and BS05are arranged as a ladder filter coupled between an RF port RF and an antenna port ANT. The RF port RF can be a transmit port of a transmit filter. The RF port can be a receive port of a receive filter. Any suitable number of series resonators and any suitable number of shunt resonators can be included in the acoustic wave filter212. The other series acoustic wave resonators BS01, BS02, BS03, BS04, and BS05can be FBARs. In some other instances, the other shunt acoustic wave BS01, BS02, BS03, BS04, and BS05can be SAW resonators or SMRs.

FIG.21Cis a schematic diagram of an acoustic wave filter214that includes a series Lamb wave resonator LS and other acoustic wave resonators B01to B08coupled to an antenna port ANT via the series Lamb wave resonator LS according to an embodiment. The other acoustic wave resonators B01to B08can be SAW resonators or BAW resonators.

FIG.21Dis a schematic diagram of an acoustic wave filter216that includes a series Lamb wave resonator LS and other acoustic wave resonators B02to B09coupled to a radio frequency port RF via the series Lamb wave resonator LS according to an embodiment. The other acoustic wave resonators B02to B09can be SAW resonators or BAW resonators.

FIG.21Eis a schematic diagram of an acoustic wave filter218that includes a series Lamb wave resonator LS and other acoustic wave resonators B01to B04and B06to B09according to an embodiment. In the acoustic wave filter218, a first other series resonator B01is coupled between the series Lamb wave resonator LS and the RF port RF. A second other series resonator B09is coupled between the series Lamb wave resonator LS and the antenna port ANT in the acoustic wave filter218. The other acoustic wave resonators B01to B04and B06to B09can be SAW resonators or BAW resonators.

FIG.21Fis a schematic diagram of an acoustic wave filter219that includes a shunt Lamb wave resonator LP and other acoustic wave resonators B01to B05and B07to B09according to an embodiment.

In the acoustic wave filter219, a first other series resonator B01is coupled between the shunt Lamb wave resonator LP and the RF port RF. A second other series resonator B09is coupled between the shunt Lamb wave resonator LP and the antenna port ANT in the acoustic wave filter219. The other acoustic wave resonators B01to B05and B07to B09can be SAW resonators or BAW resonators.

The acoustic wave devices and/or loop circuits discussed herein can be implemented in a variety of packaged modules. Some example packaged modules will now be discussed in which any suitable principles and advantages of the Lamb wave loop circuits discussed herein can be implemented.FIGS.22A,22B,22C, and22Dare schematic block diagrams of illustrative packaged modules according to certain embodiments.

FIG.22Ais a schematic block diagram of a module220that includes a duplexer222with a Lamb wave loop circuit and an antenna switch223. The module220can include a package that encloses the illustrated elements. The duplexer222with a Lamb wave loop circuit and the antenna switch223can be disposed on a common packaging substrate. The packaging substrate can be a laminate substrate, for example. The duplexer222can include a Lamb wave loop circuit in accordance with any suitable principles and advantages discussed herein. The antenna switch223can be a multi-throw radio frequency switch. The antenna switch223can selectively electrically couple a common node of the duplexer222to an antenna port of the module220.

FIG.22Bis a schematic block diagram of a module220′ that includes a first filter222A with a Lamb wave loop circuit, a second filter222B with a Lamb wave loop circuit, and an antenna switch223′. The module220′ illustrates that two different filters with Lamb wave loop circuits can be included in a module. The first filter222A with a Lamb wave loop circuit can be implemented on a different die than the second filter222B with a Lamb wave loop circuit. The antenna switch223′ can selectively electrically couple a port of the first filter222A and/or the second filter222B to an antenna port of the module220′.

FIG.22Cis a schematic block diagram of a module224that includes a power amplifier225, a switch226, and a duplexer222with a Lamb wave loop circuit. The power amplifier225can amplify a radio frequency signal. The switch226can selectively electrically couple an output of the power amplifier225to a transmit port of the duplexer222. The duplexer222can include a Lamb wave loop circuit in accordance with any suitable principles and advantages discussed herein.

FIG.22Dis a schematic block diagram of a module227that includes power amplifier225, a switch226, a duplexer222with a Lamb wave loop circuit, and an antenna switch223. The module227is similar to the module224ofFIG.22C, except the module227additionally includes the antenna switch223.

The acoustic wave filters with a Lamb wave resonator and/or another type of acoustic wave resonator disclosed herein can be implemented in a variety of packaged modules. Some example packaged modules will now be discussed in which any suitable principles and advantages of the acoustic wave filters with a Lamb wave resonator and a different type of acoustic wave resonator discussed herein can be implemented.FIGS.23A,23B, and23Care schematic block diagrams of illustrative packaged modules according to certain embodiments.

FIG.23Ais a schematic block diagram of a module230that includes one or more filters232with a Lamb wave resonator and another type of acoustic wave resonator. The one or more filters232can include any suitable combination of features disclosed in association withFIGS.20to21F. The module230can include a package that encloses the illustrated elements. The one or more filters232with a Lamb wave resonator and another type of acoustic wave resonator and the antenna switch233can be disposed on a common packaging substrate. The packaging substrate can be a laminate substrate, for example. The antenna switch233can be a multi-throw radio frequency switch. The antenna switch233can selectively electrically couple any suitable number of the one or more of the filters232to an antenna port of the module230.

FIG.23Bis a schematic block diagram of a module234that includes a power amplifier235, a switch236, and one or more filters232with a Lamb wave resonator and another type of acoustic wave resonator. The power amplifier235can amplify a radio frequency signal. The switch236can selectively electrically couple an output of the power amplifier235to a transmit port of the duplexer232. The one or more filters232with a Lamb wave resonator and another type of acoustic wave resonator can be implemented in accordance with any suitable principles and advantages discussed herein.

FIG.23Cis a schematic block diagram of a module237that includes power amplifier235, a switch236, one or more filters232with a Lamb wave resonator and another type of acoustic wave resonator, and an antenna switch233. The module237is similar to the module234ofFIG.23B, except the module237additionally includes the antenna switch233.

FIG.24is a schematic block diagram of a wireless communication device240that includes filters243with one or more Lamb wave elements in accordance with one or more embodiments. For example, the filters243can include a duplexer with a Lamb wave loop circuit in accordance with any suitable principles and advantages disclosed herein. The filters243can include a first filter with a Lamb wave resonator and a second filter with a different type of acoustic wave resonator, in which the Lamb wave resonator and the different type of acoustic wave resonator are implemented on a common substrate of a die. In certain instances, the filters243can include a filter that includes a Lamb wave resonator and a different type of acoustic wave resonator.

The wireless communication device240can be any suitable wireless communication device. For instance, a wireless communication device240can be a mobile phone, such as a smart phone. As illustrated, the wireless communication device240includes an antenna241, an RF front end242that includes the filters243, an RF transceiver244, a processor245, a memory246, and a user interface. The antenna241can transmit RF signals provided by the RF front end242. The antenna241can receive RF signals and provide the received RF signals to the RF front end242for processing.

The RF front end242can include 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 diplexers or other frequency multiplexing circuit, or any suitable combination thereof. The filters243of the RF front end242can be implemented in accordance with any suitable principles and advantages disclosed herein. The RF front end242can transmit and receive RF signals associated with any suitable communication standards. Any of the acoustic wave devices and/or Lamb wave loop circuits discussed herein can be implemented in the RF front end242.

The RF transceiver244can provide RF signals to the RF front end242for amplification and/or other processing. The RF transceiver244can also process an RF signal provided by a low noise amplifier of the RF front end242. The RF transceiver244is in communication with the processor245. The processor245can be a baseband processor. The processor245can provide any suitable base band processing functions for the wireless communication device240. The memory246can be accessed by the processor245. The memory246can store any suitable data for the wireless communication device240. The user interface247can be any suitable user interface, such as a display with touch screen capabilities.

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 some 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 in a range from about 30 kHz to 300 GHz, such as in a range from about 450 MHz to 8.5 GHz.

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, 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 stereo system, a digital music player, a radio, a camera such as a digital camera, a portable memory chip, a washer, a dryer, a washer/dryer, a copier, a facsimile machine, a scanner, a multi-functional peripheral device, a wrist watch, a clock, etc. Further, the electronic devices can include unfinished products.

Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” “include,” “including” and the like are to 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.” The word “coupled”, 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. 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. The word “or” in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list.

Moreover, 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. Thus, such conditional language is not generally 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 for deciding, with or without author input or prompting, whether these features, elements and/or states are included or are to be performed in any particular embodiment.

While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosure. Indeed, the novel apparatus, methods, and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in 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 presented in a given arrangement, alternative embodiments may perform similar functionalities with different components and/or circuit topologies, and some blocks may be deleted, moved, added, subdivided, combined, and/or modified. Each of these blocks may be implemented in a variety of different ways. Any suitable combination of the elements and acts of the various embodiments described above can be combined to provide 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.