SURFACE ACOUSTIC WAVE DEVICE COMPRISING MULTI-LAYER INTERDIGITAL TRANSDUCER ELECTRODE

A surface acoustic wave device includes a piezoelectric substrate and a multi-layer interdigital transducer electrode disposed on the piezoelectric substrate. The multi-layer interdigital transducer electrode includes a first electrode layer and a second electrode layer. The second electrode layer is disposed between the piezoelectric substrate and the first electrode layer. The first electrode layer has a higher density than a density of the second electrode layer. The second electrode layer has a higher conductivity than a conductivity of the first electrode layer. Related radio frequency modules and wireless communication devices are also provided.

BACKGROUND

Field

Aspects and embodiments disclosed herein relate to surface acoustic wave devices. More particularly, at least some embodiments are directed to radio frequency modules and wireless communication devices having surface acoustic wave devices.

Description of the Related Technology

A surface acoustic wave filter can include a plurality of resonators arranged to filter a radio frequency signal. Each resonator can include a surface acoustic wave (SAW) device. The SAW device comprises a plurality of electrodes arranged as interleaved fingers on top of a piezoelectric substrate and attached to one or more busbars linking a subset of the electrodes together. The SAW device generates acoustic waves which propagate across the piezoelectric substrate between the electrodes. Surface acoustic wave filters can be implemented in radio frequency electronic systems. For instance, filters in a radio frequency front end of a mobile phone can include surface acoustic wave filters.

SUMMARY

According to one embodiment, there is provided a surface acoustic wave device including a piezoelectric substrate and a multi-layer interdigital transducer electrode disposed on the piezoelectric substrate. The multi-layer interdigital transducer electrode includes a first electrode layer and a second electrode layer. The second electrode layer is disposed between the piezoelectric substrate and the first electrode layer. The first electrode layer has a higher density than a density of the second electrode layer. The second electrode layer has a higher conductivity than a conductivity of the first electrode layer.

In one example the first electrode layer is made mainly of tungsten.

In one example the first electrode layer has a thickness of between 100 nanometers and 500 nanometers. The first electrode layer may have a thickness of between 300 nanometers and 500 nanometers. The first electrode layer may have a thickness of 400 nanometers.

In one example the first electrode layer has a density of at least 10 grams per cubic centimeter. In one example the first electrode layer has a density of at least 19 grams per cubic centimeter.

In one example the first electrode layer is the uppermost layer of the multi-layer interdigital transducer electrode.

In one example the second electrode layer is made mainly of copper.

In one example the second electrode layer has a conductivity of at least 4×107Siemens per meter. In one example the second electrode layer has a conductivity of at least 5×107Siemens per meter. In one example the second electrode layer has a conductivity of at least 5.9×107Siemens per meter.

In one example the second electrode layer has a thickness of between 100 nanometers and 500 nanometers. The second electrode layer may have a thickness of between 100 nanometers and 300 nanometers. The second electrode layer may have a thickness of 200 nanometers.

In one example the first electrode layer has a greater thickness than a thickness of the second electrode layer. The thickness of the first electrode layer may be at least two times higher than the thickness of the second electrode layer.

In one example the first electrode layer has a thickness that is substantially the same as a thickness of the second electrode layer.

In one example the second electrode layer has an upper surface in contact with a lower surface of the first electrode layer.

In one example the second electrode layer has a lower surface in contact with an upper surface of the piezoelectric substrate.

In one example the difference between a coefficient of thermal expansion of the second electrode layer and a coefficient of thermal expansion of the first electrode layer is no more than 18 ppm/degree K. The difference between a coefficient of thermal expansion of the second electrode layer and a coefficient of thermal expansion of the first electrode layer may be no more than 15 ppm/degree K. The difference between a coefficient of thermal expansion of the second electrode layer and a coefficient of thermal expansion of the first electrode layer may be no more than 13 ppm/degree K.

In one example the multi-layer interdigital transducer electrode further includes a third electrode layer disposed between the piezoelectric substrate and the second electrode layer.

In one example the third electrode layer is made mainly of tungsten. In one example the third electrode layer is made mainly of titanium.

In one example the third electrode layer has an upper surface in contact with a lower surface of the second electrode layer.

In one example the third electrode layer has a lower surface in contact with an upper surface of the piezoelectric substrate.

In one example the third electrode layer has a density of at least 10 grams per cubic centimeter. In one example the third electrode layer has a density of at least 19 grams per cubic centimeter.

In one example the third electrode layer has a higher density than the density of the second electrode layer.

In one example the third electrode layer has a lower conductivity than the conductivity of the second electrode layer.

In one example the third electrode layer is made mainly of the same material as a material forming the first electrode layer.

In one example the difference between a coefficient of thermal expansion of the second electrode layer and a coefficient of thermal expansion of the third electrode layer is no more than 18 ppm/degree K. The difference between a coefficient of thermal expansion of the second electrode layer and a coefficient of thermal expansion of the first electrode layer may be no more than 15 ppm/degree K. The difference between a coefficient of thermal expansion of the second electrode layer and a coefficient of thermal expansion of the first electrode layer may be no more than 13 ppm/degree K

In one example the multi-layer interdigital transducer electrode further includes an adhesion layer disposed between the piezoelectric substrate and the second electrode layer. Where the multi-layer interdigital transducer electrode further includes a third electrode layer disposed between the piezoelectric substrate and the second electrode layer, the adhesion layer may be disposed between the piezoelectric substrate and the third electrode layer.

The adhesion layer may have a thickness of less than 30 nanometers. The adhesion layer may have a thickness of less than 20 nanometers. The adhesion layer may have a thickness of less than 15 nanometers. The adhesion layer may have a thickness of less than 10 nanometers.

In one example the adhesion layer is made mainly of titanium.

In one example the multi-layer interdigital transducer electrode further includes a fourth electrode layer disposed between the piezoelectric substrate and the third electrode layer. The fourth layer may be the adhesion layer recited above. The adhesion layer may be referred to as an etch stop layer.

In one example the surface acoustic wave device further includes a layer of dielectric material disposed on an upper surface of the piezoelectric substrate and an upper surface of the multi-layer interdigital transducer electrode.

The multi-layer interdigital transducer electrode may include plural electrode fingers disposed on the piezoelectric substrate. Where the surface acoustic wave device further includes a layer of dielectric material disposed on an upper surface of the piezoelectric substrate and an upper surface of the multi-layer interdigital transducer electrode, the layer of dielectric material may be free of voids between the fingers of the multi-layer interdigital transducer electrode.

Each upper surface and each lower surface of each electrode layer of the multi-layer interdigital transducer electrode described herein may be substantially parallel with the upper surface of the substrate.

According to another embodiment, there is provided a wafer-level package that includes a piezoelectric substrate and a multi-layer interdigital transducer electrode disposed on the piezoelectric substrate. The multi-layer interdigital transducer electrode includes a first electrode layer and a second electrode layer. The second electrode layer is disposed between the piezoelectric substrate and the first electrode layer. The first electrode layer has a higher density than a density of the second electrode layer. The second electrode layer has a higher conductivity than a conductivity of the first electrode layer.

The wafer-level package may include one or more suitable features of any of the surface acoustic wave devices discussed herein.

According to another embodiment, there is provided a radio frequency module including a power amplifier configured to provide a radio frequency signal, and a surface acoustic wave filter configured to filter the radio frequency signal. The surface acoustic wave filter includes a piezoelectric substrate and a multi-layer interdigital transducer electrode disposed on the piezoelectric substrate. The multi-layer interdigital transducer electrode includes a first electrode layer and a second electrode layer. The second electrode layer is disposed between the piezoelectric substrate and the first electrode layer. The first electrode layer has a higher density than a density of the second electrode layer. The second electrode layer has a higher conductivity than a conductivity of the first electrode layer.

The radio frequency module may include one or more suitable features of any of the surface acoustic wave devices discussed herein.

According to another embodiment, there is provided a wireless communication device including a surface acoustic wave filter configured to provide a filtered radio frequency signal. The surface acoustic wave filter includes a piezoelectric substrate and a multi-layer interdigital transducer electrode disposed on the piezoelectric substrate. The multi-layer interdigital transducer electrode includes a first electrode layer and a second electrode layer. The second electrode layer is disposed between the piezoelectric substrate and the first electrode layer. The first electrode layer has a higher density than a density of the second electrode layer. The second electrode layer has a higher conductivity than a conductivity of the first electrode layer.

The wireless communication device may include one or more suitable features of any of the surface acoustic wave devices discussed herein.

DETAILED DESCRIPTION

Aspects and embodiments described herein are directed to a surface acoustic wave (SAW) device having a multi-layer interdigital transducer electrode disposed on a piezoelectric substrate.

FIG.1Ais a schematic plan view of an exemplary conventional SAW resonator device10.FIG.1Bis a schematic cross-sectional view of the SAW resonator device10at line1B-1B shown inFIG.1A. The SAW resonator10includes a piezoelectric substrate2carrying an interdigital transducer (IDT) electrode8. The IDT electrode8is disposed on the piezoelectric substrate2such that the IDT electrode8is in contact with an upper surface5of the piezoelectric substrate2. The piezoelectric substrate2may be a lithium niobate (LiNbO3) based substrate.

The IDT electrode8is a comb-shaped electrode having plural electrode fingers3disposed on the upper surface5of the piezoelectric substrate2. Electrode fingers3are configured to excite a surface wave, such as Rayleigh wave, as a main acoustic wave. The conventional SAW resonator10ofFIGS.1A and1Bmay typically have 10 to 15 or more reflector fingers in each of the reflector gratings110, with each finger separated by a distance equal to half the wavelength of a surface acoustic wave generated by the IDT8.

The SAW resonator device10also includes a dielectric film4disposed above upper surface5of the piezoelectric substrate2to cover plural electrode fingers3. The dielectric film4is therefore in contact with the upper surface5of the piezoelectric substrate2and also in contact with the upper surface6of plural electrode fingers3. The dielectric film4may be made of oxide, such as silicon dioxide (SiO2).

To minimize losses in a SAW device, such as the SAW resonator ofFIG.1AandFIG.1Bit can be desirable for the material of the IDT electrode to be hard and dense. It can therefore be desirable to make the IDT electrode from dense metals like tungsten or molybdenum due to their hardness properties. In particular, the density of such metals can make it possible to shrink the size of the die being used, while minimizing viscous losses in the SAW device.

However, the resistivity of such metals is relatively high thereby making such metals less suitable for electrical conductance. One solution to this problem is to add an aluminum layer on top of a base layer of tungsten or molybdenum when forming the IDT electrode. The lower layer of tungsten or molybdenum can provide desirable hardness and density properties to the IDT electrode, while the upper layer of aluminum can increase the overall electrical conductivity of IDT electrode.

It has been appreciated by the present inventors that, while an upper layer of aluminum can increase conductivity for the IDT electrode, pure aluminum still has a relatively low tensile and compressive strength. Consequently, even with a two layer aluminum and tungsten IDT electrode structure, the IDT electrode could still benefit from improved torsional and bending rigidity, and potentially even improved conductance.

As will become apparent from the following description and the information presented by accompanyingFIGS.2A to2F,3A,3B,4A,4B,5A, and5B, embodiments of the present invention concern novel and improved multilayer IDT electrodes, which are both hard and rigid while also highly conductive, to thereby minimize both resistive loss and viscous loss. In general, the present inventors have found that such improvements can be obtained when providing the multilayer IDT electrode with an upper layer that is denser than a lower, yet more conductive layer, such as is shown by Examples A, B, D and E ofFIG.2A,FIG.2B,FIG.2D, andFIG.2E.

The present inventors have also identified copper as a particularly desirable metal to bring conductivity properties to the IDT electrode. Since copper is about three times as dense as pure aluminum, forming a layer of the IDT electrode from copper, as opposed to aluminum, can improve the overall density and hardness of the IDT electrode. Copper is also more conductive than aluminum and so also improves the electrical conductance of the IDT electrode. In particular, the resistivity of copper is generally about 1.7×10−8ohm meters, whereas the resistivity of aluminum is generally about 2.7×10−8ohm meters.

The present inventors have also identified the combination of a copper layer with a tungsten layer as being particularly desirable combination to utilize in the multilayer IDT electrode. This is at least partly due to the closer thermal match that copper has with tungsten as compared to aluminum. This may help with heat dissipation and other thermal factors for the IDT electrode.

Improvements have also been identified when arranging for the multilayer IDT electrode to be formed of at least three layers, with a second layer being sandwiched between a first layer and a third layer, and where the second (middle) layer is formed of a material that is more conductive, yet less dense than the material(s) forming the first layer and the third layer. For example, as is shown by Examples B, D and E ofFIG.2B,FIG.2DandFIG.2E, it can be desirable for the multilayer IDT electrode to be formed of three layers, with a copper layer being sandwiched between a layer of tungsten and a layer of tungsten or titanium. With such arrangements, the top and bottom layers of the sandwich structure may take the majority of the compressive and tensile loads when the multilayer IDT electrode is perturbed.

FIG.2Ashows a schematic cross-sectional view of a surface acoustic wave (SAW) device100according to a first embodiment of the present invention (hereinafter referred to as “Example A”). The SAW device100includes a piezoelectric substrate2carrying a multilayer interdigital transducer (IDT) electrode108. The multilayer IDT electrode108includes a first electrode layer101made of tungsten and a second electrode layer102made of copper. The second electrode layer102is disposed between the piezoelectric substrate2and the first electrode layer101. In particular, the second electrode layer102has an upper surface in contact with a lower surface of the first electrode layer101. The second electrode layer102also has a lower surface in contact with an upper surface of the piezoelectric substrate2. In the first embodiment of the present invention shown inFIG.2A, the first electrode layer101is the uppermost layer of the multilayer IDT electrode108. The first electrode layer101may have a thickness of 400 nanometers in direction A. The second electrode layer102may have a thickness of 200 nanometers in direction A.

FIG.2Bshows a schematic cross-sectional view of a surface acoustic wave (SAW) device200according to a second embodiment of the present invention (hereinafter referred to as “Example B”). The SAW device200includes a piezoelectric substrate2carrying a multilayer interdigital transducer (IDT) electrode208. The multilayer IDT electrode208includes a first electrode layer201made of tungsten and a second electrode layer202made of copper. The second electrode layer202is disposed between the piezoelectric substrate2and the first electrode layer201. In particular, the second electrode layer202has an upper surface in contact with a lower surface of the first electrode layer201.

The multilayer IDT electrode208of Example B also includes a third electrode layer203disposed between the piezoelectric substrate2and the second electrode layer202. The third electrode layer203is made of tungsten. The third electrode layer203has a lower surface in contact with an upper surface of the piezoelectric substrate2. The third electrode layer203also has an upper surface in contact with a lower surface of the second electrode layer202. The multilayer IDT electrode208of Example B therefore consists of three layers. The first electrode layer201has a thickness of 200 nanometers in direction A. The second electrode layer202may have a thickness of 200 nanometers in direction A. The third electrode layer203may have a thickness of 200 nanometers in direction A.

FIG.2Cshows a schematic cross-sectional view of a first example surface acoustic wave (SAW) device300(hereinafter referred to as “Example C”). The SAW device300includes a piezoelectric substrate2carrying a multilayer interdigital transducer (IDT) electrode308. The multilayer IDT electrode308includes a first electrode layer301made of copper and a second electrode layer302made of tungsten. The second electrode layer302is disposed between the piezoelectric substrate2and the first electrode layer301. In particular, the second electrode layer302has an upper surface in contact with a lower surface of the first electrode layer301. The second electrode layer302also has a lower surface in contact with an upper surface of the piezoelectric substrate2. In Example C, the first electrode layer301is the uppermost layer of the multilayer IDT electrode308. The first electrode layer301may have a thickness of 200 nanometers in direction A. The second electrode layer302may have a thickness of 400 nanometers in direction A.

FIG.2Dshows a schematic cross-sectional view of a surface acoustic wave (SAW) device400according to a third embodiment of the present invention (hereinafter referred to as “Example D”). The SAW device400includes a piezoelectric substrate2carrying a multilayer interdigital transducer (IDT) electrode408. The multilayer IDT electrode408includes a first electrode layer401and a second electrode layer402. The second electrode layer402is disposed between the piezoelectric substrate2and the first electrode layer401. In particular, the second electrode layer402has an upper surface in contact with a lower surface of the first electrode layer401.

The multilayer IDT electrode408of Example D also includes a third electrode layer403disposed between the piezoelectric substrate2and the second electrode layer402. The third electrode layer403has an upper surface in contact with a lower surface of the second electrode layer402. The third electrode layer403is made of tungsten.

The multilayer IDT electrode408of Example D also includes a fourth electrode layer404disposed between the piezoelectric substrate2and the third electrode layer403. The fourth electrode layer404has a lower surface in contact with an upper surface of the piezoelectric substrate2. The fourth electrode layer404has an upper surface in contact with a lower surface of the third electrode layer403. The fourth electrode layer404is made of titanium. The fourth electrode layer404may act as an adhesion layer to assist with securing the multilayer IDT electrode408to the piezoelectric substrate2.

The multilayer IDT electrode408of Example D therefore consists of four layers. The first electrode layer401may have a thickness of 200 nanometers in direction A. The second electrode layer402may have a thickness of 200 nanometers in direction A. The third electrode layer403may have a thickness of 200 nanometers in direction A. The fourth electrode layer404may have a thickness of 15 nanometers in direction A. The above specified thickness values for the first, second, third and fourth layers401,402,403and404are merely exemplary values, and other suitable thicknesses may be adopted based on the desired properties of the multilayer IDT electrode408.

FIG.2Eshows a schematic cross-sectional view of a surface acoustic wave (SAW) device500according to a fourth embodiment of the present invention (hereinafter referred to as “Example E”). The SAW device500includes a piezoelectric substrate2carrying a multilayer interdigital transducer (IDT) electrode508. The multilayer IDT electrode508includes a first electrode layer501made of tungsten and a second electrode layer502made of copper. The second electrode layer502is disposed between the piezoelectric substrate2and the first electrode layer501. In particular, the second electrode layer502has an upper surface in contact with a lower surface of the first electrode layer501.

The multilayer IDT electrode508of Example E also includes a third electrode layer503disposed between the piezoelectric substrate2and the second electrode layer502. The third electrode layer503is made of titanium. The third electrode layer503has a lower surface in contact with an upper surface of the piezoelectric substrate2. The third electrode layer503also has an upper surface in contact with a lower surface of the second electrode layer502. The multilayer IDT electrode508of Example E therefore consists of three layers. The first electrode layer501may have a thickness of 200 nanometers in direction A. The second electrode layer502may have a thickness of 200 nanometers in direction A. The third electrode layer503may have a thickness of 200 nanometers in direction A.

FIG.2Fshows a schematic cross-sectional view of a second example surface acoustic wave (SAW) device600(hereinafter referred to as “Example F”). The SAW device600includes a piezoelectric substrate2carrying a multilayer interdigital transducer (IDT) electrode608. The multilayer IDT electrode608includes a first electrode layer601made of aluminum and a second electrode layer602made of tungsten. The second electrode layer602is disposed between the piezoelectric substrate2and the first electrode layer601. In particular, the second electrode layer602has an upper surface in contact with a lower surface of the first electrode layer601. The second electrode layer602also has a lower surface in contact with an upper surface of the piezoelectric substrate2. In Example F, the first electrode layer601is the uppermost layer of the multilayer IDT electrode608. The first electrode layer601may have a thickness of 200 nanometers in direction A. The second electrode layer602may have a thickness of 400 nanometers in direction A.

FIGS.3A,4A and5Ashow various comparisons of admittance plotted against frequency for the surface acoustic wave devices of Examples A, B, C, D, E and F.FIGS.3B,4B and5Bshow various comparisons of quality factor plotted against frequency for the surface acoustic wave devices of Examples A, B, C, D, E and F. Advantages concerning Examples A, B, D, and E, in particular, will be readily understood by one of skill in the art when having regard toFIGS.3A,3B,4A,4B,5A and5Band the above description.

It should be appreciated that the surface acoustic wave resonators illustrated inFIGS.2A to2F, as well as the other circuit elements illustrated in other figures presented herein, are illustrated in a highly simplified form. The relative dimensions of the different features are not shown to scale. Further, typical surface acoustic wave resonators would commonly include a far greater number of electrode fingers in the IDTs than illustrated. Similarly, the number of reflector fingers shown inFIGS.1A,1BandFIGS.2A to2F(described below) are not intended to be representative of the number of reflector fingers included within the reflector gratings, which is instead described in the text of the description.

The surface acoustic wave devices and/or multi-layer interdigital transducer electrodes described herein can be included in a wafer-level package. A wafer-level package refers to a integrated circuit that is packaged while still part of a wafer, as opposed to separating the wafer into individual dies and packaging each die separately. The resulting wafer-level package is a chip-scale package because the package is the same size as, or only marginally larger than, the size of the die. The integrated circuit can include a SAW device.

The surface acoustic wave devices described herein can be included in a filter. A filter that includes one or more surface acoustic wave devices can be referred to as a surface acoustic wave filter. Surface acoustic wave devices can be arranged as series resonators and shunt resonators to form a ladder filter. In some instances, a filter can include surface acoustic wave resonators and one or more other resonators (e.g., one or more other bulk acoustic wave resonators).

The filters discussed herein can be implemented in a variety of modules. Some example modules will now be discussed in which any suitable principles and advantages of the filters discussed herein can be implemented.FIGS.6,7, and8are schematic block diagrams of illustrative modules according to certain embodiments. A module arranged to process a radio frequency signal can be referred to as a radio frequency (RF) module.

Surface acoustic wave devices can be included in a filter. A filter that includes one or more surface acoustic wave devices can be referred to as a surface acoustic wave filter. Surface acoustic wave devices can be arranged as series resonators and shunt resonators to form a ladder filter. In some instances, a filter can include surface acoustic wave resonators and one or more other resonators (e.g., one or more other bulk acoustic wave resonators).

The filters discussed herein can be implemented in a variety of modules. Some example modules will now be discussed in which any suitable principles and advantages of the filters discussed herein can be implemented.FIGS.6,7, and8are schematic block diagrams of illustrative modules according to certain embodiments. A module arranged to process a radio frequency signal can be referred to as a radio frequency (RF) module.

FIG.6is a schematic block diagram of a module1200that includes a power amplifier1202, a switch1204, and filters1206in accordance with one or more embodiments. The module1200can include a package that encloses the illustrated elements. The power amplifier1202, the switch1204, and the filters1206can be disposed on a common packaging substrate. The packaging substrate can be a laminate substrate, for example. The power amplifier1202can amplify a radio frequency signal. The power amplifier1202can include a gallium arsenide bipolar transistor in certain applications. The switch1204can be a multi-throw radio frequency switch. The switch1204can electrically couple an output of the power amplifier1202to a selected filter of the filters1206. The filters1206can include any suitable number of surface acoustic wave filters and/or other acoustic wave filters. One or more of the surface acoustic wave filters of the filters1206can be implemented in accordance with any suitable principles and advantages of the surface acoustic wave devices discussed herein.

FIG.7is a schematic block diagram of a module1201that includes power amplifiers1202A and1202B, switches1204A and1204B, and filters1206′ in accordance with one or more embodiments. The module1201is like the module1200ofFIG.6, except that the module1201includes an additional power amplifier1202B and an additional switch1204B and the filters1206′ are arranged to filter signals for the signal paths associated with a plurality of power amplifiers1202A and1202B. The different signal paths can be associated with different frequency bands and/or different modes of operation (e.g. different power modes, different signaling modes, etc.).

FIG.8is a schematic block diagram of a module1203that includes power amplifiers1202A and1202B, switches1204A and1204B, and filters1206A and1206B in accordance with one or more embodiments, and an antenna switch1208. The module1203is like the module1201ofFIG.7, except the module1203includes an antenna switch1208arranged to selectively couple a signal from the filters1206A or the filters1206B to an antenna node. The filters1206A and1206B can correspond to the filters1206′ ofFIG.7.

FIG.9is a schematic diagram of one embodiment of a wireless communication device or mobile device1300. The mobile device1300includes a baseband system1301, a transceiver1302, a front end system1303, antennas1304, a power management system1305, a memory1306, a user interface1307, and a battery1308.

Although the mobile device1300illustrates one example of an RF system that can include one or more features of the present disclosure, the teachings herein are applicable to electronic systems implemented in a wide variety of ways.

The transceiver1302generates RF signals for transmission and processes incoming RF signals received from the antennas1304. It will be understood that various functionalities associated with the transmission and receiving of RF signals can be achieved by one or more components that are collectively represented inFIG.9as the transceiver1302. In one example, separate components (for instance, separate circuits or dies) can be provided for handling certain types of RF signals.

As shown in inFIG.9, the transceiver1302is connected to the front end system1303and to the power management circuit1305using a serial interface1309. All or part of the illustrated RF components can be controlled by the serial interface1309to configure the mobile device1300during initialization and/or while fully operational. In another embodiment, the baseband processor1301is additionally or alternative connected to the serial interface1309and operates to configure one or more RF components, such as components of the front end system1303and/or power management system1305.

The front end system1303aids in conditioning signals transmitted to and/or received from the antennas1304. In the illustrated embodiment, the front end system1303includes one or more bias control circuits1310for controlling power amplifier biasing, one or more power amplifiers (PAs)1311, one or more low noise amplifiers (LNAs)1312, one or more filters1313, one or more switches1314, and one or more duplexers1315. However, other implementations are possible.

For example, the front end system1303can provide a number of functionalities, including, but not limited to, amplifying signals for transmission, amplifying received signals, filtering signals, switching between different bands, switching between different power modes, switching between transmission and receiving modes, duplexing of signals, multiplexing of signals (for instance, diplexing or triplexing), or some combination thereof.

The antennas1304can include antennas used for a wide variety of types of communications. For example, the antennas1304can include antennas for transmitting and/or receiving signals associated with a wide variety of frequencies and communications standards.

The mobile device1300can operate with beamforming in certain implementations. For example, the front end system1303can include phase shifters having variable phase controlled by the transceiver1302. Additionally, the phase shifters are controlled to provide beam formation and directivity for transmission and/or reception of signals using the antennas1304. For example, in the context of signal transmission, the phases of the transmit signals provided to the antennas1304are controlled such that radiated signals from the antennas1304combine using constructive and destructive interference to generate an aggregate transmit signal exhibiting beam-like qualities with more signal strength propagating in a given direction. In the context of signal reception, the phases are controlled such that more signal energy is received when the signal is arriving to the antennas1304from a particular direction. In certain implementations, the antennas1304include one or more arrays of antenna elements to enhance beamforming.

The baseband system1301is coupled to the user interface1307to facilitate processing of various user input and output (I/O), such as voice and data. The baseband system1301provides the transceiver1302with digital representations of transmit signals, which the transceiver1302processes to generate RF signals for transmission. The baseband system1301also processes digital representations of received signals provided by the transceiver1302. As shown inFIG.9, the baseband system1301is coupled to the memory1306to facilitate operation of the mobile device1300.

The memory1306can be used for a wide variety of purposes, such as storing data and/or instructions to facilitate the operation of the mobile device1300and/or to provide storage of user information.

The power management system1305provides a number of power management functions of the mobile device1300. In certain implementations, the power management system1305includes a power amplifier (PA) supply control circuit that controls the supply voltages of the power amplifiers1311. For example, the power management system1305can be configured to change the supply voltage(s) provided to one or more of the power amplifiers1311to improve efficiency, such as power added efficiency (PAE).

The power management system1305can operate in a selectable supply control mode, such an average power tracking (APT) mode or an envelope tracking (ET) mode. In the illustrated embodiment, the selected supply control mode of the power management system1305is controlled by the transceiver1302. In certain implementations, the transceiver1302controls the selected supply control mode using the serial interface1309.

As shown inFIG.9, the power management system1305receives a battery voltage from the battery1308. The battery1308can be any suitable battery for use in the mobile device1300, including, for example, a lithium-ion battery. Although the power management system1305is illustrated as separate from the front end system1303, in certain implementations all or part (for instance, a PA supply control circuit) of the power management system1305is integrated into the front end system1303.