Patent ID: 12206387

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.

Acoustic wave filters can filter radio frequency (RF) signals in a variety of applications, such as in an RF front end of a mobile phone. An acoustic wave filter can be implemented with surface acoustic wave (SAW) devices. Certain SAW devices may be referred as SAW resonators. A SAW resonator can be configured to generate, for example, a Rayleigh mode surface acoustic wave or a shear horizontal mode surface acoustic wave.

Acoustic wave filters can include SAW resonators that include a single layer piezoelectric substrate and an interdigital transducer (IDT) electrode over the single layer piezoelectric substrate. The single layer piezo substrate can consist of a piezoelectric layer. The piezoelectric layer can be a lithium niobate (LN) piezoelectric layer, for example. Such SAW resonators can degrade the reflection coefficient gamma. For example, such SAW resonators can generate higher order response at about 1.3 times and 1.8 times the main resonance. This can lower the reflection coefficient. A multiplexer that includes such SAW resonators may suffer from insertion loss (IL) degradation.

Multi-layer piezoelectric substrate SAW resonators can include a bonded substrate to improve a quality factor (Q) of the resonator. In various instances, such a bonded substrate has caused a reflection at a bonding interface such that a higher-order reflection may occur at a higher frequency and degrade the reflection coefficient. Degradation in the reflection coefficient can result in IL degradation in a multiplexer.

Aspects of this disclosure relate to a SAW resonator with a multi-layer piezoelectric substrate. Multi-layer piezoelectric substrates can provide good thermal dissipation characteristics and improved temperature coefficient of frequency (TCF) relative to certain single layer piezoelectric substrates. For example, certain SAW resonators with a piezoelectric layer on a high impedance layer, such as silicon, can achieve better temperature coefficient of frequency (TCF) and thermal dissipation compared to similar devices without the high impedance layer.

Embodiments of a SAW resonator disclosed herein include a piezoelectric layer that has a cut angle in a range from 115° to 135°. As used herein, a “cut angle” of N° refers to an N° rotated Y-cut in a Y-cut X-propagation piezoelectric layer. For a piezoelectric layer with Euler angles (φ, θ, ψ), the “cut angle” in degrees can be θ plus 90°. Accordingly, the second Euler angle θ can be in a range from 25° to 45° when the cut angle is in the range from 115° to 135°. The piezoelectric layer with such cut angle can provide a resonator having less reflection degradation over a relatively broad frequency range as compared to multi-layer piezoelectric substrate with a piezoelectric layer that has other cut angles (e.g., a cut angle in a range from −10° to 60°). The first Euler angle φ can be in a range from −10° to +10°. The third Euler angle θ can be in a range from −10° to +10°. In certain embodiments, the Euler angles (φ, θ, ψ) can be (0°, 25°<θ<45°, 0°).

Embodiments of a SAW resonator disclosed herein can also include a low acoustic impedance layer that has an acoustic impedance lower than that of the high impedance layer. The low acoustic impedance layer can be disposed between the piezoelectric layer and the high impedance layer. Embodiments of a SAW resonator disclosed herein can include a temperature compensation layer over the IDT electrode in addition to or as an alternative to the low acoustic impedance layer.

FIG.1illustrates a cross section of a surface acoustic wave (SAW) resonator1. The illustrated SAW resonator1includes an LN layer10, IDT electrodes12over the LN layer10, and a silicon dioxide (SiO2) layer14over the IDT electrodes12. The LN layer10has a cut angle of 122°. The IDT electrode12of the SAW resonator1has a pitch L that sets the wavelength λ of the surface acoustic wave device1. The pitch L of the illustrated IDT electrode12of the SAW resonator1is 2 μm. The pitch L is typically equal to the wavelength λ. A thickness of the LN layer10of the SAW resonator1can be in a range from 100 μm to 500 μm, for example. In simulations, the LN layer10can be modeled has having a semi-infinite thickness. A thickness of the SiO2layer14of the SAW resonator1is 0.3 L. The IDT electrode12of the SAW resonator1is a multi-layer IDT electrode. The IDT electrodes12include a molybdenum (Mo) layer and an aluminum (Al) layer over the Mo layer. The Mo layer has a thickness of 0.04 L.

FIG.2illustrates a cross section of a surface acoustic wave (SAW) resonator2according to one embodiment. The SAW resonator2includes a piezoelectric layer20, IDT electrodes22over the piezoelectric layer20, and a temperature compensating layer24over the IDT electrodes22. The SAW resonator2also includes a high impedance layer26under the piezoelectric layer20. The SAW resonator2can generate a Rayleigh mode surface acoustic wave.

The piezoelectric layer20can include any suitable piezoelectric material. For example, the piezoelectric layer20can be a lithium niobate (LN) with a cut angle in a range from 115° to 135°. With the cut angle of a piezoelectric layer20that is LN being within a range from 115° to 135°, the SAW resonator2can generate a Rayleigh mode surface acoustic wave. By contrast, a similar SAW resonator with an LN piezoelectric layer having a cut angle in a range from 20° to 30° can generate a shear horizontal surface acoustic wave and suppress a Rayleigh mode surface acoustic wave. In some embodiments, the piezoelectric layer20can be an LN layer with a cut angle of 122°.

The IDT electrodes22can include any suitable IDT electrode material. For example, the IDT electrodes22can include one or more of an aluminum (Al) layer, a molybdenum (Mo) layer, a tungsten (W) layer, a titanium (Ti) layer, a platinum (Pt) layer, a gold (Au) layer, a silver (Ag) layer, a copper (Cu) layer, a Magnesium (Mg) layer, a ruthenium (Ru) layer, or the like. The IDT electrode22may include alloys, such as AlMgCu, AlCu, etc. In some embodiments, the IDT electrodes22can be multi-layer IDT electrodes. As an example, a multi-layer IDT electrode can include an Al layer over a Mo layer, or an Al layer over a W layer.

The temperature compensating layer24can include any suitable temperature compensating material. For example, the temperature compensating layer24can be a silicon dioxide (SiO2) layer. The temperature compensating layer24can be a layer of any other suitable material having a positive temperature coefficient of frequency in instances where the piezoelectric layer20has a negative temperature coefficient of frequency. For instance, the temperature compensating layer24can be a tellurium dioxide (TeO2) layer or a silicon oxyfluoride (SiOF) layer in certain applications. The temperature compensating layer24can include any suitable combination of SiO2, TeO2, and/or SiOF. The temperature compensating layer24can bring the TCF of the surface acoustic wave resonator2closer to zero to thereby provide temperature compensation. The temperature compensating layer24can improve the electromechanical coupling coefficient k2of the SAW resonator2relative to a similar SAW resonator without the temperature compensating layer24. This advantage of the temperature compensating layer24can be more pronounced when the piezoelectric layer20includes an LN layer.

An acoustic impedance of the high impedance layer26can be higher than an acoustic impedance of the piezoelectric layer20. The acoustic impedance of the high impedance layer26can be higher than an acoustic impedance of the temperature compensating layer24. The high impedance layer26can include any suitable material so long as the acoustic impedance of the high impedance layer26is higher than at least one of the acoustic impedance of the piezoelectric layer20or the acoustic impedance of the temperature compensating layer24. The acoustic impedance of the high impedance layer26can be higher than an acoustic impedance of silicon dioxide. In certain embodiments, the high impedance layer26can be a silicon (Si) layer. In some other embodiments, the high impedance layer26can include, for example, aluminum nitride (AlN), silicon nitride (SiN), sapphire, spinel, high impedance glass, etc. As discussed with respect toFIG.3, the high impedance layer26together with a particular cut angle of the piezoelectric layer20can improve the reflection coefficient of a SAW resonator.

The piezoelectric layer20has a thickness T1. The thickness T1of the piezoelectric layer20can be selected based on a wavelength λ or L of a surface acoustic wave generated by the surface acoustic wave resonator2. The IDT electrode22has a pitch that sets the wavelength λ or L of the surface acoustic wave device2. The piezoelectric layer20can be sufficiently thick to provide good coupling factor. A thickness T1of the piezoelectric layer20of at least 0.1 L can be sufficiently thick to mitigate degradation of the coupling factor due to a relatively thin piezoelectric layer20. The thickness T1of the piezoelectric layer20can be in a range from, for example, 0.1 L to 0.5 L. In some instances, the thickness T1of the piezoelectric layer20can be in a range from 0.3 L to 0.5 L. The wavelength L of the surface acoustic wave can be, for example, 2 μm and the thickness T1of the piezoelectric layer20can be, for example, 0.6 μm, in some embodiments. As noted above, the piezoelectric layer20can be an LN layer or any other suitable piezoelectric layer (e.g., a lithium tantalate (LT) layer).

The temperature compensating layer24has a thickness T2. In some embodiments, the thickness T2of the temperature compensating layer24can be in a range from 0.01 L to 0.4 L. For example, when the wavelength L is 2 μm, the thickness T2of the temperature compensating layer24can be 0.8 μm.

The IDT electrodes12has a thickness T3. In some embodiments, the thickness T3can be about 0.04 L. In some embodiments, the thickness T3can be in a range from 0.01 L to 0.08 L. For example, when the wavelength L is 2 μm, the thickness T3of the Mo layer18can be 80 nm.

The high impedance layer26has a thickness T4. In some embodiments, the thickness T4can be determined based at least in part on acoustic energy confirmation. In some embodiments, the thickness T4can be greater than 10 μm or 1 L. A thickness T4of at least 10 μm can provide a desired level of mechanical durability. The thickness T4can be in a range from 10 μm to 1000 μm. The upper bound of the thickness T4can be based on a final device or module height constraint.

FIG.3is a graph showing simulated results of reflection coefficient s11(Γ) of the SAW resonator1and the SAW resonator2illustrated inFIGS.1and2respectively. A thickness of the LN layer10of the SAW resonator1is set to a semi-infinite condition in the simulation. The SAW resonator2used in the simulation has the following specification: The pitch L is 2 μm; the piezoelectric layer20is an LN layer with a cut angle of 122° and the thickness T1of 0.3 L; the IDT electrodes22are Mo electrodes with the thickness T3of 0.04 L; the temperature compensating layer24is a SiO2layer with the thickness T2of 0.1 L; and the high impedance layer26is a Si layer with the thickness T4of a semi-infinite condition. In certain instances, the high impedance layer26can be a Si layer with a thickness in a range from 10 μm to 1000 μm.

The simulated result of the SAW resonator1shows some degradations around 2.4 GHz and 3.4 GHz, while the simulated result of the SAW resonator2shows a clean gamma below 3.5 GHz. As shown inFIG.3, the gamma for the SAW resonator2can be relatively high (e.g., more than 0.9 or more than 0.95) for frequencies that are below 3.5 GHz and above a passband of a filter that includes the SAW resonator2. This improvement in the gamma for the SAW resonator2can be due to the high impedance layer26together with the cut angle of the piezoelectric layer20.

FIG.4illustrates a cross section of a surface acoustic wave resonator3. The illustrated SAW resonator3includes an LN layer30, IDT electrodes32over the LN layer30, and a SiO2layer34over the IDT electrodes32. The LN layer30has a cut angle of 128°. The IDT electrode32of the SAW resonator3has a pitch L that sets the wavelength λ of the surface acoustic wave device3. The pitch L of the illustrated IDT electrode of the SAW resonator3is 2.5 μm. A thickness of the SiO2layer34of the SAW resonator3is 0.3 L. The IDT electrodes32of the SAW resonator3is a multi-layer IDS. The IDT electrodes32include a molybdenum (Mo) layer and an aluminum (Al) layer over the Mo layer. The Mo layer has a thickness of 0.04 L.

FIG.5illustrates a cross section of a surface acoustic wave resonator4. The illustrated SAW resonator4includes a lithium tantalate (LT) layer40, and IDT electrodes42over the LT layer40. The SAW resonator4also includes a Si layer46under the LT layer40and a SiO2layer48between the LT layer40and the Si layer46. The LT layer40has a cut angle of 42°. The IDT electrode32of the SAW resonator4has a pitch L that sets the wavelength λ of the surface acoustic wave device4. The pitch L of the illustrated IDT electrode of the SAW resonator4is 2.6 μm. A thickness of the LT layer40of the SAW resonator4is 0.3 L. The IDT electrodes42of the SAW resonator4are aluminum (Al) electrodes. The IDT electrodes42have a thickness of 0.08 L. A thickness of the SiO2layer48of the SAW resonator4is 0.3 L.

FIG.6illustrates a cross section of a surface acoustic wave resonator5according to one embodiment. The SAW resonator5is similar to the SAW resonator2illustrated inFIG.2. Unless otherwise noted, the components ofFIG.5may be similar to or the same as like numbered components ofFIG.2. Like the SAW resonator2, the SAW resonator5includes a piezoelectric layer20, IDT electrodes22′ over the piezoelectric layer20, a temperature compensating layer24over the IDT electrodes22, and a high impedance layer26under the piezoelectric layer20. Unlike the SAW resonator2, the SAW resonator5also includes a low impedance layer28. The SAW resonator5can generate Rayleigh mode surface acoustic waves.

Unlike the IDT electrodes22of SAW resonator2, the illustrated IDT electrodes22′ of the SAW resonator5are multi-layer IDT electrodes. The IDT electrodes22′ include a bottom layer23and an upper layer25. Like the IDT electrodes22of the SAW resonator2, the IDT electrides22′ of the SAW resonator5can include an aluminum (Al) layer, a molybdenum (Mo) layer, a tungsten (W) layer, a titanium (Ti) layer, a platinum (Pt) layer, a gold (Au) layer, a silver (Ag) layer, copper (Cu) layer, a Magnesium (Mg) layer, etc. The IDT electrode22′ may include alloys, such as AlMgCu, AlCu, etc. In certain embodiments, the IDT electrodes22′ can be Al/Mo multi-layer electrodes where the bottom layer23is a Mo layer and the upper layer25is an Al layer. In some other embodiments, the IDT electrodes22′ can be Al/W multi-layer electrodes where the bottom layer23is a W layer and the upper layer25is an Al layer. The bottom layer23has a thickness T3′. The thickness T3′ of the bottom layer23can be in a range from 0.01 L to 0.08 L.

An acoustic impedance of the low impedance layer28can be lower than the acoustic impedance of the high impedance layer26. In some embodiments, the low impedance layer can be a silicon dioxide (SiO2) layer. Some low impedance layers, such as an SiO2layer, can provide a greater adhesion strength between the low impedance layer and the high impedance layer26than a adhesion strength between the piezoelectric layer20and the high impedance layer26. As discussed with respect toFIG.7, the low impedance layer28can contribute to improvement in the reflection coefficient of a SAW resonator.

The low impedance layer28has a thickness T5. In some embodiments, the thickness T5of the low impedance layer28can be in a rage from 0.01 L to 0.3 L. In some embodiments, the thickness T5of the low impedance layer28can be 0.1 L. When the wavelength is, for example, 2.3 μm, the thickness T5can be 230 nm.

FIG.7shows simulation results of isolation s12in decibels (dB) on the left and reflection coefficient s11(gamma or Γ) on the right for ladder filters using the SAW resonators3,4and5ofFIGS.4,5and6, respectively. The SAW resonator6used in the simulation has the following specification: The pitch L is 2.3 μm; the piezoelectric layer20is an LN layer with a cut angle of 124° and the thickness T1of 0.3 L; the IDT electrodes22′ are Al/Mo multi-layer electrodes with the thickness T3′ of the Al layer of 0.04 L; the temperature compensating layer24is a SiO2layer with the thickness T2of 0.2 L; the high impedance layer26is a Si layer with the thickness T4set to a semi-infinite condition; and the low impedance layer28is another SiO2layer with the thickness T5of 0.1 L.

FIG.7includes a chart32that shows band names with center frequencies in MHz and bandwidths in MHz. The ladder filters with the SAW resonators3,4, and5for the simulation results shown inFIG.7were Band32filters. The simulation results inFIG.7indicate that the ladder filter with SAW resonators5has the best Γ of the simulated ladder filters.FIG.7indicates that Γ for the Band32filter with SAW resonators5is relatively high for frequencies corresponding to Band3transmit, Band3receive, Band1transmit, Band1receive, Band40, Band66transmit, Band25transmit, Band25receive, Band66receive, Band30transmit, and Band30receive. Accordingly, a Band32filter with SAW resonators5can be included in a multiplexer with one or more other filters arranged to filter any of the frequency bands shown in chart32without significantly degrading insertion loss.

As illustrated inFIG.7, the Γ of the SAW resonator3and the Γ of the SAW resonator4degrades at frequency range of between about 1.7 GHz to about 2.5 GHz. On the other hand, the Γ of the SAW resonator5is relatively clean at the same frequency range. This improvement in the gamma Γ for the SAW resonator5may be due to the high impedance layer26and/or the low impedance layer28together with the cut angle of the piezoelectric layer.

FIGS.8A,9A,10A,11A,12A,13A,14A,15A,16A,17A,18A,19A,20A,21A, and22Aillustrate SAW resonators according to various embodiments.FIGS.8B,9B,10B,11B,12B,13B,14B,15B,16B,17B,18B,19B,20B,21B, and22Billustrate simulation results showing isolation s12on the left and reflection coefficient s11(Γ) on the right for the SAW resonators ofFIGS.8A,9A,10A,11A,12A,13A,14A,15A,16A,17A,18A,19A,20A,21A, and22A, respectively.

FIG.8Aillustrates a cross section of a SAW resonator6. Unless otherwise noted, the components ofFIG.8Amay be similar to or the same as like numbered components ofFIG.2. The SAW resonator6includes a piezoelectric layer20, IDT electrodes22over the piezoelectric layer20, and a high impedance layer26under the piezoelectric layer80. Unlike the SAW resonator2illustrated inFIG.2, the SAW resonator6does not include the temperature compensating layer24. The SAW resonator6can generate Rayleigh mode surface acoustic waves.

The SAW resonator6can have a pitch L of 2 μm, for example. The piezoelectric layer20of the SAW resonator6illustrated inFIG.8Ais a lithium niobate (LN) layer with a cut angle of 120°. The IDT electrodes22of the SAW resonator6are aluminum (Al) electrodes with a thickness T3of 0.04 L. The high impedance layer26of the SAW resonator6is a silicon (Si) layer with a thickness T4set to a semi-infinite condition.

FIG.8Billustrates graphs showing simulation results of isolation s12on the left and reflection coefficient s11(Γ) on the right for the SAW resonator6ofFIG.8A. The simulation results are for five different thicknesses T1of the piezoelectric layer20. The simulations were performed with the thicknesses T1of 0.1 L, 0.2 L, 0.3 L, 0.4 L, and 0.5 L.

FIG.9Aillustrates a cross section of a SAW resonator7according to one embodiment. The SAW resonator7is like the SAW resonator6illustrated inFIG.8Aexcept that the SAW resonator7also includes a low impedance layer28. The low impedance layer28of the SAW resonator7illustrated inFIG.9Ais a silicon dioxide (SiO2) layer with a thickness T5of 0.05 L for the simulation results shown inFIG.9B.

FIG.9Billustrates graphs showing simulation results of isolation s12on the left and reflection coefficient s11(Γ) on the right for the SAW resonator7ofFIG.9A. The simulation results are for five different thicknesses T1of the piezoelectric layer20. The simulations were performed with the thicknesses T1of 0.1 L, 0.2 L, 0.3 L, 0.4 L, and 0.5 L. As compared to the simulation results of the SAW resonator6, the Γ is improved in the simulation results of the SAW resonator7. Accordingly, the low impedance layer28can contribute to improved Γ in a Rayleigh mode SAW resonator.

FIG.10Aillustrates a cross section of a SAW resonator8according to one embodiment. The SAW resonator8is like the SAW resonator7illustrated inFIG.9Aexcept that the low impedance layer28of the SAW resonator8illustrated inFIG.9Ahas a thickness T5of 0.1 L.

FIG.10Billustrates graphs showing simulation results of isolation s12on the left and reflection coefficient s11(Γ) on the right for the SAW resonator8ofFIG.10A. The simulation results are for five different thicknesses T1of the piezoelectric layer20. The simulations were performed with the thicknesses T1of 0.1 L, 0.2 L, 0.3 L, 0.4 L, and 0.5 L. As compared to the simulation results of the SAW resonator6, the Γ is improved in the simulation results of the SAW resonator8.

FIG.11Aillustrates a cross section of a SAW resonator9according to one embodiment. The SAW resonator9is like the SAW resonator7illustrated inFIG.9Aexcept that the low impedance layer28of the SAW resonator9illustrated inFIG.11Ahas a thickness T5of 0.2 L.

FIG.11Billustrates graphs showing simulation results of isolation s12on the left and reflection coefficient s11(Γ) on the right for the SAW resonator9ofFIG.11A. The simulation results are for five different thicknesses T1of the piezoelectric layer20. The simulations were performed with the thicknesses T1of 0.1 L, 0.2 L, 0.3 L, 0.4 L, and 0.5 L.

FIG.12Aillustrates a cross section of a SAW resonator51according to one embodiment. The SAW resonator51is like the SAW resonator7illustrated inFIG.9Aexcept that the low impedance layer28of the SAW resonator51illustrated inFIG.12Ahas a thickness T5of 0.3 L.

FIG.12Billustrates graphs showing simulation results of isolation s12on the left and reflection coefficient s11(Γ) on the right for the SAW resonator51ofFIG.12A. The simulation results are for five different thicknesses T1of the piezoelectric layer20. The simulations were performed with the thicknesses T1of 0.1 L, 0.2 L, 0.3 L, 0.4 L, and 0.5 L. These simulations indicate that when the lower impedance layer28is sufficiently thick, Γ can be degraded.

FIG.13Aillustrates a cross section of a SAW resonator52according to one embodiment. The SAW resonator52is like the SAW resonator2illustrated in FIG.2A. The SAW resonator52can have a pitch L of 2 μm. The piezoelectric layer20of the SAW resonator52illustrated inFIG.13Ais a lithium niobate (LN) layer with a cut angle of 120°. The IDT electrodes22of the SAW resonator52are aluminum (Al) electrodes with a thickness T3of 0.04 L. The temperature compensating layer24is a silicon dioxide (SiO2) layer with a thickness T2of 0.1 L. The high impedance layer26of the SAW resonator6is a silicon (Si) layer.

FIG.13Billustrates graphs showing simulation results of isolation s12on the left and reflection coefficient s11(Γ) on the right for the SAW resonator52ofFIG.13A. The simulation results are for five different thicknesses T1of the piezoelectric layer20. The simulations were performed with the thicknesses T1of 0.1 L, 0.2 L, 0.3 L, 0.4 L, and 0.5 L.

FIG.14Aillustrates a cross section of SAW resonator53according to one embodiment. The SAW resonator53is like the SAW resonator52illustrated inFIG.13Aexcept that the temperature compensating layer24of the SAW resonator53illustrated inFIG.14Ahas a thickness T5of 0.2 L.

FIG.14Billustrates graphs showing simulation results of isolation s12on the left and reflection coefficient s11(Γ) on the right for the SAW resonator53ofFIG.14A. The simulation results are for five different thicknesses T1of the piezoelectric layer20. The simulations were performed with the thicknesses T1of 0.1 L, 0.2 L, 0.3 L, 0.4 L, and 0.5 L.

FIG.15Aillustrates a cross section of a SAW resonator54according to one embodiment. The SAW resonator54is like the SAW resonator52illustrated inFIG.13Aexcept that the temperature compensating layer24of the SAW resonator54illustrated inFIG.15Ahas a thickness T5of 0.3 L.

FIG.15Billustrates graphs showing simulation results of isolation s12on the left and reflection coefficient s11(Γ) on the right for the SAW resonator54ofFIG.15A. The simulation results are for five different thicknesses T1of the piezoelectric layer20. The simulations were performed with the thicknesses T1of 0.1 L, 0.2 L, 0.3 L, 0.4 L, and 0.5 L.

FIG.16Aillustrates a cross section of a SAW resonator55according to one embodiment. The SAW resonator55is like the SAW resonator5illustrated inFIG.6, except that the SAW resonator55has a single layer IDT electrodes22instead of the multi-layer IDT electrodes22′ illustrated inFIG.6.

The SAW resonator55has a pitch L of 2 μm for the simulation corresponding toFIG.16B. The piezoelectric layer20of the SAW resonator55illustrated inFIG.16Ais a lithium niobate (LN) layer with a cut angle of 120°. The IDT electrodes22of the SAW resonator6are aluminum (Al) electrodes with a thickness T3of 0.04 L for the simulation corresponding toFIG.16B. The temperature compensating layer24is a silicon dioxide (SiO2) layer with a thickness T2of 0.1 L. The high impedance layer26of the SAW resonator55is a silicon (Si) layer. The low impedance layer28of the SAW resonator55is a silicon dioxide (SiO2) layer with a thickness T5of 0.1 L.

FIG.16Billustrates graphs showing simulation results of isolation s12on the left and reflection coefficient s11(Γ) on the right for the SAW resonator55ofFIG.16A. The simulation results are for five different thicknesses T1of the piezoelectric layer20. The simulations were performed with the thicknesses T1of 0.1 L, 0.2 L, 0.3 L, 0.4 L, and 0.5 L.

When Al IDT electrodes are used as IDT electrodes22, an open grating may be outside of a short grating. Such stopband performance may be undesirable. On the other hand, when IDT electrodes of a material that has a higher density than Al (e.g., molybdenum (Mo), tungsten (W), etc.) are used, the stopband performance may be improved. When the temperature compensating layer24is a silicon dioxide (SiO2) layer and has a thickness T2that is larger than 0.15 L, and Mo IDT electrodes are used, majority of the open grating can be within the short grating, which may indicate that the stopband performance is improved relative to the resonator with Al electrodes. Similarly, when the temperature compensating layer24is a silicon dioxide (SiO2) layer and has a thickness T2that is larger than 0.1 L, and W IDT electrodes are used, majority of the open grating can be within the short grating, which may indicate that the stopband performance is improved relative to the resonator with Al electrodes.

FIG.17Aillustrates a cross section of a SAW resonator56. The SAW resonator56is like the SAW resonator6illustrated inFIG.8Aexcept that the IDT electrodes22of the SAW resonator56illustrated inFIG.17Aare molybdenum (Mo) IDT electrodes with a thickness T3of 0.4 L.

FIG.17Billustrates graphs showing simulation results of isolation s12on the left and reflection coefficient s11(Γ) on the right for the SAW resonator56ofFIG.17A. The simulation results are for five different thicknesses T1of the piezoelectric layer20. The simulations were performed with the thicknesses T1of 0.1 L, 0.2 L, 0.3 L, 0.4 L, and 0.5 L.

FIG.18Aillustrates a cross section of a SAW resonator57according to one embodiment. The SAW resonator57is like the SAW resonator56illustrated inFIG.17Aexcept that the SAW resonator57also includes a low impedance layer28. The low impedance layer28of the SAW resonator57illustrated inFIG.18Ais a silicon dioxide (SiO2) layer with a thickness T5of 0.1 L for the simulation corresponding toFIG.18B.

FIG.18Billustrates graphs showing simulation results of isolation s12on the left and reflection coefficient s11(Γ) on the right for the SAW resonator57ofFIG.18A. The simulation results are for five different thicknesses T1of the piezoelectric layer20. The simulations were performed with the thicknesses T1of 0.1 L, 0.2 L, 0.3 L, 0.4 L, and 0.5 L. As compared to the simulation results of the SAW resonator56, the Γ is improved in the simulation results of the SAW resonator57. Accordingly, the low impedance layer28can contribute to improved Γ in the SAW resonator57.

FIG.19Aillustrates a cross section of a SAW resonator58according to one embodiment. The SAW resonator58is like the SAW resonator57illustrated inFIG.18Aexcept that the SAW resonator58illustrated inFIG.19Aalso includes a temperature compensating layer24. The temperature compensating layer24of the SAW resonator58is a silicon dioxide (SiO2) layer with a thickness T2of 0.1 L for the simulation corresponding toFIG.19B.

FIG.19Billustrates graphs showing simulation results of isolation s12on the left and reflection coefficient s11(Γ) on the right for the SAW resonator58ofFIG.19A. The simulation results are for five different thicknesses T1of the piezoelectric layer20. The simulations were performed with the thicknesses T1of 0.1 L, 0.2 L, 0.3 L, 0.4 L, and 0.5 L. As compared to the simulation results of the SAW resonator56, the Γ is improved in the simulation results of the SAW resonator58.

FIG.20Aillustrates a cross section of a SAW resonator59according to one embodiment. The SAW resonator59is like the SAW resonator58illustrated in FIG.19A except that the temperature compensating layer24of the SAW resonator59illustrated inFIG.20Ahas a thickness T5of 0.2 L.

FIG.20Billustrates graphs showing simulation results of isolation s12on the left and reflection coefficient s11(Γ) on the right for the SAW resonator59ofFIG.14A. The simulation results are for five different thicknesses T1of the piezoelectric layer20. The simulations were performed with the thicknesses T1of 0.1 L, 0.2 L, 0.3 L, 0.4 L, and 0.5 L. As compared to the simulation results of the SAW resonator56, the Γ is improved in the simulation results of the SAW resonator59.

FIG.21Aillustrates a cross section of a SAW resonator60according to one embodiment. The SAW resonator60is like the SAW resonator57illustrated inFIG.18Aexcept that the piezoelectric layer20of the SAW resonator60illustrated inFIG.20Ahas a thickness T1of 0.3 L.

FIG.21Billustrates graphs showing simulation results of isolation s12on the left and reflection coefficient s11(Γ) on the right for the SAW resonator60ofFIG.21A. The simulation results are for five different cut angles of the piezoelectric layer20. The simulations were performed with the cut angles of 120°, 122°, 124°, 126°, and 128°. The graph of reflection coefficient ofFIG.21Bindicates that spikes are affected by the cut angle of the piezoelectric layer20.FIG.21Bindicates that the cut angle of the piezoelectric layer20can affect gamma.

FIG.22Aillustrates a cross section of a SAW resonator61according to one embodiment. The SAW resonator61is like the SAW resonator5illustrated inFIG.6, except that the SAW resonator55has a single layer IDT electrodes22instead of the multi-layer IDT electrodes22′ illustrated inFIG.6and various features of the layers (e.g., cut angle, material and/or thickness) are indicated inFIG.16A.

The SAW resonator61is illustrated with a pitch L of 2 μm. The piezoelectric layer20of the SAW resonator61illustrated inFIG.22Ais a lithium niobate (LN) layer. The piezoelectric layer20of the SAW resonator61has a thickness T1of 0.3 L. The IDT electrodes22of the SAW resonator61have a thickness T3of 0.04 L. The IDT electrodes22of the SAW resonator61can be tungsten or molybdenum. The temperature compensating layer24of the SAW resonator61is a silicon dioxide (SiO2) layer with a thickness T2of 0.2 L. The high impedance layer26of the SAW resonator61is a silicon (Si) layer. The low impedance layer28of the SAW resonator61is a silicon dioxide (SiO2) layer with a thickness T5of 0.1 L.

FIG.22Billustrates a cross section of a SAW resonator62. The illustrated SAW resonator62is like the SAW resonator1illustrated inFIG.1with a single layer IDT electrode. The SAW resonator62includes an LN layer10′, IDT electrodes12′ over the LN layer10′, and an SiO2layer14′ over the IDT electrodes12′. The LN layer10′ has a cut angle of 126°. The pitch L of the SAW resonator62is 2 μm. A thickness of the SiO2layer14′ of the SAW resonator62is 0.2 L. The IDT electrodes12′ of the SAW resonator62are molybdenum (Mo) IDT electrodes. The IDT electrodes12′ a thickness of 0.04 L.

FIG.22Cillustrates graphs showing simulation results of isolation s12on the left and reflection coefficient s11(Γ) on the right for the SAW resonators61and62ofFIGS.22A and22B, respectively. The curves for the SAW resonator61have lithium niobate piezoelectric layers with cut angles of 122° and 124°. The simulations were performed with tungsten (W) IDT electrodes and molybdenum (Mo) IDT electrodes for the SAW resonator61. As compared to the simulation result of the SAW resonator62, the Γ is improved in the simulation results of the SAW resonator61.

FIG.23Aillustrates graphs showing simulation results of isolation s12on the left and reflection coefficient s11(Γ) on the right for the SAW resonators61and62ofFIGS.22A and22Brespectively. The simulations were performed with molybdenum (Mo) IDT electrodes and LN layers with a cut angle of 120° for the SAW resonator61and the SAW resonator62. The differences in the graphs ofFIGS.22C and23Acan be due to differences in cut angle.

FIG.23Billustrates transmission leakage of the SAW resonator61illustrated inFIG.22Aat a frequency of 4 GHz.FIG.23Cillustrates transmission leakage of the SAW resonator62ofFIG.22Bat a frequency of 4 GHz. The acoustic leakage is reduced for the SAW resonator61as compared to the acoustic leakage of the SAW resonator62.

FIG.24illustrates graphs showing simulated dispersion curves of a SAW resonator having various thicknesses of silicon dioxide (SiO2) layer over a molybdenum (Mo) IDT electrode. The simulations were performed with the SiO2layer having thicknesses of 0 (no SiO2layer over the IDT electrode), 0.01 L, 0.02 L, 0.03 L, 0.05 L, 0.1 L, 0.15 L, 0.2 L, 0.25 L, 0.3 L, 0.35 L, and 0.4 L. Each of the graphs show a short grating dispersion curve and an open grating dispersion curve. The x-axis shows frequency and the y-axis shows wave number. These graphs indicate that, when the thickness of the SiO2layer is more than about 0.15 L, the dispersion is better than when the thickness of the SiO2layer is less than about 0.15 L.

From these simulation results of the SAW resonators according to various embodiments, desirable resonator structures can be determined for particular operations. For example, the determination of a thickness T1of the piezoelectric layer20, a thickness T2of the temperature compensating layer24, a thickness T4of the high impedance layer26, and/or a thickness T5of the low impedance layer28can be based at least in part on the simulated reflection coefficient (Γ). For example, a material for the piezoelectric layer20, a cut angle of the piezoelectric layer20, and/or a material for the IDT electrodes22,22′ can be determined based at least in part on the simulated reflection coefficient (Γ). The simulated reflection coefficient (Γ) of the SAW resonators in various embodiments can be analyzed to determine a suitable structure of a SAW resonator for certain applications.

The simulation results indicate that the high impedance layer26and/or the low acoustic impedance layer28affect the wide range gamma. Therefore, a selection of suitable thicknesses and/or materials for the high impedance layer26and/or the low acoustic impedance layer28can improve the wide range gamma. For example, the simulation results indicate that using a silicon dioxide (SiO2) layer with a thickness in a range from 0.01 L to 0.3 L, such as a thickness of about 0.1 L, as the low acoustic impedance layer28can improve the wide range gamma.

The simulation results indicate that the temperature compensating layer24and/or the cut angle of the piezoelectric layer20affect the narrow range gamma. Therefore, a selection of suitable thicknesses or materials for the temperature compensating layer24and/or the piezoelectric layer20can improve the narrow range gamma. For example, the simulation results indicate that using a silicon dioxide (SiO2) layer with a thickness greater than about 0.15 L as the temperature compensating layer24can improve the narrow range gamma. By using such SiO2layer as temperature compensating layer, a resonator can obtain reflection characteristics similar to a TC-SAW resonator.

The simulation results indicate that a lithium niobate (LN) layer with cut angle in a range from 118° to 138°, such as a cut angle of about 128°, can be a suitable piezoelectric layer to use in embodiments disclosed herein. The simulation results indicate that an LN layer with a thickness in a range from 0.1 L to 0.5 L, such as a thickness of about 0.3 L, can be a suitable piezoelectric layer to use in various embodiments disclosed herein. The simulation results indicate that the Mo IDT electrodes or the W IDT electrodes improve an electromechanical coupling coefficient k2relative to the Al IDT electrodes.

In some instances, a SAW resonator according to one embodiment can have, referring to reference numerals used inFIG.6, a silicon (Si) layer (as the high impedance layer26), a silicon dioxide (SiO2) layer with a thickness of 0.1 L (as the low impedance layer28) over the Si layer, a lithium noibate (LN) layer with a cut angle of 124° and a thickness of 0.3 L (as the piezoelectric layer20) over the SiO2layer, an aluminum/molybdenum (Al/Mo) IDT electrodes with a Mo thickness of 0.04 L (as the IDT electrodes22′) over the LN layer, and another silicon dioxide (SiO2) layer with a thickness of 0.2 L (as the temperature compensating layer24) over the IDT electrodes. In some other instances, a SAW resonator according to one embodiment can have a silicon (Si) layer, a silicon dioxide (SiO2) layer with a thickness of 0.1 L over the Si layer, a120YX lithium noibate (LN) layer with a thickness of 0.3 L over the SiO2layer, and an aluminum/molybdenum (Al/Mo) IDT electrodes with a Mo thickness of 0.04 L over the LN layer. Such structure can be generally similar to the SAW resonator57illustrated inFIG.18A. Such structure, unlike the IDT electrode22of the SAW resonator57, has the Al layer over the Mo layer.

Any of the SAW resonators with the temperature compensating layer disclosed herein may also include a dispersion adjustment layer over the temperature compensating layer. The dispersion adjustment layer can have a trench, in some embodiments. In certain applications, the dispersion adjustment layer with the trench can suppress the transverse mode.

FIG.25Aillustrates a cross section of a surface acoustic wave resonator71according to one embodiment. The SAW resonator71is similar to the SAW resonator5illustrated inFIG.6.FIG.25Bis a top plan view of the resonator71illustrated inFIG.25A. Unless otherwise noted, the components ofFIGS.25A and25Bmay be similar to or the same as like numbered components ofFIG.6. The SAW resonator71includes a piezoelectric layer20, IDT electrodes22′ over the piezoelectric layer20, a temperature compensating layer24over the IDT electrodes22′, and a high impedance layer26under the piezoelectric layer20. The SAW resonator71also includes a low impedance layer28between the piezoelectric layer20and the high impedance layer26, and a dispersion adjustment layer80over the temperature compensating layer24.

The illustrated dispersion adjustment layer80is partially disposed over an upper surface of the temperature compensation layer24with trenches. However, the dispersion adjustment layer80can be disposed entirely over the upper surface of the temperature compensation layer24in some other instances. The dispersion adjustment layer80can cause a magnitude of the velocity in the underlying region of the SAW resonator71to be increased. The trench can reduce velocity in the underlying region of the SAW resonator71relative to regions covered by the dispersion adjustment layer80to thereby suppress transverse modes. The dispersion adjustment layer80can include a SiN layer. In certain applications, the dispersion adjustment layer80can include any suitable material to increase the magnitude of the velocity of the underlying region of a SAW resonator. According to some applications, the dispersion adjustment layer80can include SiN and another material. The dispersion adjustment layer80has a thickness T6. In some embodiments, the thickness T6of the dispersion adjustment layer80can be in a range from 0.001 L to 0.05 L.

FIG.25Cis a graph showing simulation results of admittance of the SAW resonator71ofFIG.25Aand a similar resonator without the trenches in the dispersion adjustment layer80. In the simulation: a lithium niobate (LN) piezoelectric layer with a thickness T1of 0.3 L was used as the piezoelectric layer20; an Al/Mo IDT electrodes with a thickness T3′ of the Mo layer of 0.04 L and a thickness T3″ of the Al layer of 0.04 L was used as the IDT electrodes22′; a silicon dioxide (Sift) layer with a thickness T2of 0.2 L was used as the temperature compensating layer24; a silicon (Si) layer was used as the high impedance layer26; a silicon dioxide (Sift) layer with a thickness T5of 0.1 L was used as the low impedance layer28; and a silicon nitride (SiN) layer with a thickness T6of 0.005 L was used as the dispersion adjustment layer80.

The trenches in the dispersion adjustment layer80are formed over edges of IDT fingers. A gap between a bus bar to an edge of a finger of the IDT electrode22′ can be about 0.9 L. The gap can be in a range from 0.9 L to 2 L in some embodiments. A trench width between the edge of the finger of the IDT electrode to an edge of a middle portion of the dispersion adjustment layer80can be about 1 L. The trench width can be in a range from 0.5 L to 1.5 L, in certain embodiments.

The graph shown inFIG.25Bindicates that the transverse mode is suppressed for the SAW resonator that includes the trench in the dispersion adjustment layer80, as compared to the similar resonator that does not include the trench in the dispersion adjustment layer80.

FIG.26is a schematic diagram of an example transmit filter85that includes surface acoustic wave resonators according to an embodiment. The transmit filter85can be a band pass filter. The illustrated transmit filter85is arranged to filter a radio frequency signal received at a transmit port TX and provide a filtered output signal to an antenna port ANT. Some or all of the SAW resonators TS1to TS7and/or TP1to TP5can be a SAW resonators in accordance with any suitable principles and advantages disclosed herein. For instance, one or more of the SAW resonators of the transmit filter85can be a surface acoustic wave resonator2ofFIG.2or a surface acoustic wave resonator5ofFIG.6. Alternatively or additionally, one or more of the SAW resonators of the transmit filter85can be any surface acoustic wave resonator disclosed herein. Any suitable number of series SAW resonators and shunt SAW resonators can be included in a transmit filter85.

FIG.27is a schematic diagram of a receive filter90that includes surface acoustic wave resonators according to an embodiment. The receive filter90can be a band pass filter. The illustrated receive filter90is arranged to filter a radio frequency signal received at an antenna port ANT and provide a filtered output signal to a receive port RX. Some or all of the SAW resonators RS1to RS8and/or RP1to RP6can be SAW resonators in accordance with any suitable principles and advantages disclosed herein. For instance, one or more of the SAW resonators of the receive filter90can be a surface acoustic wave resonator2ofFIG.2or a surface acoustic wave resonator5ofFIG.6. Alternatively or additionally, one or more of the SAW resonators of the receive filter90can be any surface acoustic wave resonator disclosed herein. Any suitable number of series SAW resonators and shunt SAW resonators can be included in a receive filter90.

FIG.28is a schematic diagram of a radio frequency module175that includes a surface acoustic wave component176according to an embodiment. The illustrated radio frequency module175includes the SAW component176and other circuitry177. The SAW component176can include one or more SAW resonators with any suitable combination of features of the SAW resonators disclosed herein. The SAW component176can include a SAW die that includes SAW resonators.

The SAW component176shown inFIG.28includes a filter178and terminals179A and179B. The filter178includes SAW resonators. One or more of the SAW resonators can be implemented in accordance with any suitable principles and advantages of the surface acoustic wave resonator2ofFIG.2, a surface acoustic wave resonator5ofFIG.6, and/or any surface acoustic wave resonator disclosed herein. The filter178can be a TC-SAW filter arranged as a band pass filter to filter radio frequency signals with frequencies below about 3.5 GHz in certain applications. The terminals179A and178B can serve, for example, as an input contact and an output contact. The SAW component176and the other circuitry177are on a common packaging substrate180inFIG.28. The package substrate180can be a laminate substrate. The terminals179A and179B can be electrically connected to contacts181A and181B, respectively, on the packaging substrate180by way of electrical connectors182A and182B, respectively. The electrical connectors182A and182B can be bumps or wire bonds, for example. The other circuitry177can include any suitable additional circuitry. For example, the other circuitry can include one or more one or more power amplifiers, one or more radio frequency switches, one or more additional filters, one or more low noise amplifiers, the like, or any suitable combination thereof. The radio frequency module175can include one or more packaging structures to, for example, provide protection and/or facilitate easier handling of the radio frequency module175. Such a packaging structure can include an overmold structure formed over the packaging substrate175. The overmold structure can encapsulate some or all of the components of the radio frequency module175.

FIG.29is a schematic diagram of a radio frequency module184that includes a surface acoustic wave component according to an embodiment. As illustrated, the radio frequency module184includes duplexers185A to185N that include respective transmit filters186A1to186N1and respective receive filters186A2to186N2, a power amplifier187, a select switch188, and an antenna switch189. In some instances, the module184can include one or more low noise amplifiers configured to receive a signal from one or more receive filters of the receive filters186A2to186N2. The radio frequency module184can include a package that encloses the illustrated elements. The illustrated elements can be disposed on a common packaging substrate180. The packaging substrate can be a laminate substrate, for example.

The duplexers185A to185N can each include two acoustic wave filters coupled to a common node. The two acoustic wave filters can be a transmit filter and a receive filter. As illustrated, the transmit filter and the receive filter can each be band pass filters arranged to filter a radio frequency signal. One or more of the transmit filters186A1to186N1can include one or more SAW resonators in accordance with any suitable principles and advantages disclosed herein. Similarly, one or more of the receive filters186A2to186N2can include one or more SAW resonators in accordance with any suitable principles and advantages disclosed herein. AlthoughFIG.29illustrates duplexers, any suitable principles and advantages disclosed herein can be implemented in other multiplexers (e.g., quadplexers, hexaplexers, octoplexers, etc.) and/or in switch-plexers.

The power amplifier187can amplify a radio frequency signal. The illustrated switch188is a multi-throw radio frequency switch. The switch188can electrically couple an output of the power amplifier187to a selected transmit filter of the transmit filters186A1to186N1. In some instances, the switch188can electrically connect the output of the power amplifier187to more than one of the transmit filters186A1to186N1. The antenna switch189can selectively couple a signal from one or more of the duplexers185A to185N to an antenna port ANT. The duplexers185A to185N can be associated with different frequency bands and/or different modes of operation (e.g., different power modes, different signaling modes, etc.).

FIG.30is a schematic block diagram of a module190that includes duplexers191A to191N and an antenna switch192. One or more filters of the duplexers191A to191N can include any suitable number of surface acoustic wave resonators in accordance with any suitable principles and advantages discussed herein. Any suitable number of duplexers191A to191N can be implemented. The antenna switch192can have a number of throws corresponding to the number of duplexers191A to191N. The antenna switch192can electrically couple a selected duplexer to an antenna port of the module190.

FIG.31is a schematic block diagram of a module210that includes a power amplifier212, a radio frequency switch214, and duplexers191A to191N in accordance with one or more embodiments. The power amplifier212can amplify a radio frequency signal. The radio frequency switch214can be a multi-throw radio frequency switch. The radio frequency switch214can electrically couple an output of the power amplifier212to a selected transmit filter of the duplexers191A to191N. One or more filters of the duplexers191A to191N can include any suitable number of surface acoustic wave resonators in accordance with any suitable principles and advantages discussed herein. Any suitable number of duplexers191A to191N can be implemented.

FIG.32Ais a schematic diagram of a wireless communication device220that includes filters223in a radio frequency front end222according to an embodiment. The filters223can include one or more SAW resonators in accordance with any suitable principles and advantages discussed herein. The wireless communication device220can be any suitable wireless communication device. For instance, a wireless communication device220can be a mobile phone, such as a smart phone. As illustrated, the wireless communication device220includes an antenna221, an RF front end222, a transceiver224, a processor225, a memory226, and a user interface227. The antenna221can transmit/receive RF signals provided by the RF front end222. Such RF signals can include carrier aggregation signals. Although not illustrated, the wireless communication device220can include a microphone and a speaker in certain applications.

The RF front end222can include one or more power amplifiers, one or more low noise amplifiers, one or more RF switches, one or more receive filters, one or more transmit filters, one or more duplex filters, one or more multiplexers, one or more frequency multiplexing circuits, the like, or any suitable combination thereof. The RF front end222can transmit and receive RF signals associated with any suitable communication standards. The filters223can include SAW resonators of a SAW component that includes any suitable combination of features discussed with reference to any embodiments discussed above.

The transceiver224can provide RF signals to the RF front end222for amplification and/or other processing. The transceiver224can also process an RF signal provided by a low noise amplifier of the RF front end222. The transceiver224is in communication with the processor225. The processor225can be a baseband processor. The processor225can provide any suitable base band processing functions for the wireless communication device220. The memory226can be accessed by the processor225. The memory226can store any suitable data for the wireless communication device220. The user interface227can be any suitable user interface, such as a display with touch screen capabilities.

FIG.32Bis a schematic diagram of a wireless communication device230that includes filters223in a radio frequency front end222and a second filter233in a diversity receive module232. The wireless communication device230is like the wireless communication device200ofFIG.32A, except that the wireless communication device230also includes diversity receive features. As illustrated inFIG.32B, the wireless communication device230includes a diversity antenna231, a diversity module232configured to process signals received by the diversity antenna231and including filters233, and a transceiver234in communication with both the radio frequency front end222and the diversity receive module232. The filters233can include one or more SAW resonators that include any suitable combination of features discussed with reference to any embodiments discussed above.

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 frequency range from about 30 kHz to 300 GHz, such as in a frequency 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 die and/or acoustic wave filter assemblies and/or 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 personal digital assistant (PDA), a microwave, a refrigerator, an automobile, a stereo system, a DVD player, a CD player, a digital music player such as an MP3 player, a radio, a camcorder, a camera, 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.

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.