HK1233778A1 - Front end architecture for intermittent emissions and/or coexistence specifications - Google Patents

Description

Front-end architecture for intermittent radiation and/or coexistence specification

Technical Field

The present application relates to electronic systems, and in particular, to Radio Frequency (RF) circuits.

Background

The cellular radio frequency transmission specification (specification) typically specifies certain linearity, radiation (emission), power level, and modulation quality for nominal (nominal) operating conditions. It would be desirable to implement these specifications with relatively high efficiency. The cellular radio frequency transmission specification may also specify a particular linearity, radiation, power level, and/or modulation quality for an intermittent signaling (intermittent signaling) condition for a mobile device. Such intermittent signaling specifications may be associated with changing coexistence environments in and/or around the mobile device. Meeting worst-case intermittent specifications may involve making a compromise in efficiency (tradeoff) for nominal operating conditions. This may result in sub-optimal performance during typical operation.

Disclosure of Invention

The inventions described in the claims each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of the claims, some salient features of the application will now be briefly described.

One aspect of the present application is an apparatus that includes a first transmit path, a second transmit path, and a switching element. The first transmit path is configured to provide a first Radio Frequency (RF) signal according to a nominal specification. The second transmit path is configured to provide a second RF signal according to an intermittent specification, wherein the first RF signal and the second RF signal are within a same transmit frequency band. The switching element is coupled to both the first transmit path and the second path. The switching element is configured to provide the first RF signal as a transmit mode output in a first state and the second RF signal as the transmit mode output in a second state.

The first transmit path may include a first transmit filter and the second transmit path may include a second transmit filter, wherein the first transmit filter and the second transmit filter have approximately the same passband. The second transmit filter may have a higher out-of-band attenuation than the first transmit filter. The second transmit filter may have a higher in-band attenuation than the first transmit filter.

The first transmit path may be associated with a higher Power Added Efficiency (PAE) than the second transmit path. The second transmit path may be associated with a higher linearity than the first transmit path. The first transmit path may have a lower insertion loss than the second transmit path. In an embodiment, the second transmit path may include a band pass filter and a notch filter.

The first transmit path may receive an RF signal from a first power amplifier and the second transmit path may receive a second RF signal from a second power amplifier. The first power amplifier may be configured to operate in an envelope tracking mode and the second power amplifier may be configured to operate in an average power mode. Alternatively, the apparatus may include a selection switch configured to electrically couple an output of a power amplifier to a selected one of a plurality of throws of the selection switch, wherein the plurality of throws of the selection switch includes at least a first throw electrically coupled to the first transmit path and a second throw electrically coupled to the second transmit path.

The transmit mode output of the switching element may be electrically coupled to an antenna port. The switching element can include a multi-throw radio frequency switch having at least a first throw and a second throw, wherein the first throw is electrically coupled to the first transmit path and the second throw is electrically coupled to the second transmit path. The switching element may be, for example, a single pole, multiple throw switch. According to some other embodiments, the switching element may comprise multiple poles and multiple throws. The switching element may selectively couple one of the first transmit path, the second transmit path, or the third transmit path to an antenna port.

The intermittent specification may be, for example, the NS _07 specification. The nominal specification may be, for example, a band 13 transmission specification. In some applications, the transmission frequency bands may be from 777MHz and 787 MHz.

Another aspect of the present application is an apparatus that includes a first transmit filter, a second transmit filter, and a switching element. The first transmit filter has a passband. The second transmit filter has approximately the same passband as the first transmit filter. The second transmit filter has a higher out-of-band attenuation than the first transmit filter. The switching element is electrically coupled to both the first transmit filter and the second transmit filter.

The switching element can have at least a first throw electrically coupled to the first transmit filter and a second throw electrically coupled to the second transmit filter. The switching element can selectively electrically couple the second throw to an antenna port based at least in part on a signal indicating an intermittent signaling mode. The apparatus may also include an antenna, and the switching element may be configured to electrically couple a selected one of a plurality of throws to the antenna, wherein the plurality of throws includes the first throw and the second throw.

The second filter may provide a higher out-of-band attenuation and/or in-band attenuation than the first transmit filter. The out-of-band attenuation of the second filter may be asymmetric with respect to the passband. The higher out-of-band attenuation of the second filter may be below and/or above the passband in frequency. The first transmit filter and the second transmit filter may be included in separate duplexers. Alternatively, the first transmit filter and the second transmit filter may be included in a combined package duplexer.

The apparatus may also include a first power amplifier in communication with the first transmit filter and a second power amplifier in communication with the second transmit filter. Alternatively, the apparatus can also include a power amplifier and a selection switch configured to electrically couple an output of the power amplifier to a selected one of a plurality of throws, wherein the plurality of throws includes at least a first throw electrically coupled to the first transmit filter and a second throw electrically coupled to the second transmit filter.

Another aspect of the application is an electronically-implemented method comprising: providing a Radio Frequency (RF) signal to an antenna, wherein the RF signal is within a specified frequency band; receiving a signal associated with an intermittent radiation specification; and in response to said receiving, changing a state of a switch to cause a different RF signal according to said intermittent radiation specification to be provided to said antenna, wherein said different RF signal is within said specified frequency band.

The method may further include generating the different RF signal such that the different RF signal has a higher linearity than the RF signal.

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

Drawings

Embodiments of the present application will now be described, by way of non-limiting example, with reference to the accompanying drawings.

Fig. 1A is a schematic diagram of a front end architecture (front end architecture) according to an embodiment.

Fig. 1B is a schematic diagram of a front end structure according to an embodiment.

Fig. 1C is a graph of the frequency response of the filters in the two transmit paths of fig. 1A.

Fig. 2A is a schematic diagram of a front end structure according to another embodiment.

Fig. 2B is a schematic diagram of a front end structure according to another embodiment.

Fig. 3A is a schematic diagram of a front end structure according to another embodiment.

Fig. 3B is a schematic diagram of a front end structure according to another embodiment.

Fig. 4A is a schematic diagram of a front end structure according to another embodiment.

Fig. 4B is a schematic diagram of a front end structure according to another embodiment.

Fig. 5A-5C are diagrams of front end architectures where a particular transmit path includes a notch filter in accordance with various embodiments.

Fig. 6 is a flow diagram of an illustrative process of providing a radio frequency signal from a selected transmit path in accordance with an embodiment.

Fig. 7A and 7B are schematic diagrams of a packaged module according to some embodiments.

Fig. 8 is a schematic block diagram of an example mobile device that may include a front-end architecture having any combination of the features of the front-end architecture discussed herein. The example mobile device of fig. 8 may also perform the illustrative process of fig. 6.

Detailed Description

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

Nominal operating conditions for a cellular radio transmitter dictate certain linearity, radiation, power levels, and modulation qualities. It would be desirable to achieve these specifications with relatively high Direct Current (DC) efficiency. The intermittent radiation specification may be signaled by the network. For example, the base station can signal the mobile device to enter an intermittent radiation specification mode. This may be due to changing coexistence environments in and/or around the handset (handset). To meet worst-case intermittent specifications, tradeoffs in DC current efficiency may be made to achieve target linearity and/or out-of-band emissions specifications. Previous solutions for meeting worst-case intermittent specifications have come at the cost of meeting worst-case intermittent specifications, while penalizing (penalizing) nominal operating conditions, such as DC current consumption and/or insertion loss, that exist most of the time. This may result in sub-optimal performance during typical operation.

Aspects of the present application relate to meeting intermittent specifications while maintaining relatively high performance for typical operations. Example embodiments are provided for meeting the specification of typical Band 13(Band 13) operation and the specification of NS _07 radiated intermittent network signaling (network signaling). NS _07 requires a public safety band that is referred to as being usable by firemen, police, etc. In the Long Term Evolution (LTE) standard, the transmit band of band 13 is adjacent to the NS-07 band. There is a strict specification for the interference to NS _07 transmissions. The NS _07 special case may be signaled by the network when operating in the transmit band (777-787MHz) of band 13. When signaling NS-07 special cases, the specifications require the handset to reduce its radiation to meet the spectral radiation at the antenna less than-57 dBm/6.25kHz in the public safety band (769 + 775 MHz). This can protect the public safety band. The NS _07 public safety band is only about 2MHz from the band 13 transmit band. The proximity of the NS _07 public safety band to the band 13 transmit band can present technical problems. For example, significantly increasing filter attenuation to prevent interference between the transmit band of band 13 and the NS _07 public safety band may increase insertion loss and DC operating current for typical operation.

The NS _07 specification specifies a much greater out-of-band attenuation in the transmit path of band 13 than in nominal mode band 13 transmit operation. This increased out-of-band attenuation may be achieved by a duplexer disposed between the power amplifier and the antenna switch module. However, filters with increased out-of-band attenuation may also increase insertion loss in the transmit path of band 13. Because NS _07 mode typically occurs only a small fraction of the time (e.g., about 1% of the time or less), a solution that maintains nominal transmit DC current consumption during typical operation while meeting NS _07 specifications is desired.

In the present application, a dedicated RF path for typical transmissions in band 13 and a dedicated RF path for transmissions in band 13 while meeting the radiation specification of NS _07 common safety band are provided. One path may be implemented with relatively high efficiency for nominal operating conditions such as transmitting typical band 13 signals and the other path may be implemented with high linearity and/or out-of-band filter attenuation for intermittent conditions such as the NS-07 case. One of the two paths may be selected based on whether an intermittent condition is signaled. This may enable difficult intermittent radiation specifications to be met for penalty (penalty) during intermittent mode with higher DC current consumption, and therefore lower efficiency, without incurring similar penalty during typical operation. Thus, intermittent radiation specifications and/or coexistence specifications may be met while maintaining a relatively high level of performance, such as DC current consumption, during typical operation.

The principles and advantages discussed herein may be applied to various applications in a mobile device, such as a cellular telephone. In general, the principles and advantages discussed herein may be applied to situations where significantly more stringent (tough) radiation performance is desired intermittently, rather than every moment.

One application of the principles and advantages discussed herein is in a situation where there is intermittent radiation between radios within a single mobile device (e.g., a single handset). This may be referred to as self-sensitivity degradation (de-sense) co-existence. For example, when a mobile phone is facilitating a Long Term Evolution (LTE) call in band 41 (in the frequency range from 2496MHz to 2690 MHz), a 2.4GHz Wi-Fi connection may be started (in the frequency range from 2403MHz to 2483 MHz). In this example, it may be desirable to reduce radiation emitted from band 41 into frequency channels on 2.4GHz Wi-Fi. Without such radiation reduction, the mobile device would degrade the sensitivity of its own Wi-Fi reception. As another example, band 12 operation may be carrier aggregated with secondary receive channels in band 4. The third harmonic of band 12 is generally not a concern when operating in its own right, but in the case of band 12 transmitting/receiving the primary channel plus the last band 4 receive channel, it may be desirable to attenuate the third harmonic of band 12 up to about 100dB from its amplitude at the power amplifier output (e.g., the collector of the bipolar power amplifier transistor) so that it does not interfere with the band 4 receive path. As yet another example, a mobile device operating in frequency band 13 may have a second harmonic that approximates a Global Positioning System (GPS) frequency band. Suppression of the second harmonic of band 13 may not be of undue concern if the GPS is not operational. However, when GPS is operating (active), filtering out the second harmonic of band 13 can have a significant impact on improving performance.

Another application of the principles and advantages discussed herein is in the context of interference from the environment surrounding a mobile device. For example, when a mobile device is being used in a crowd of people, the mobile devices of other nearby users may cause interference. Alternatively or additionally, the network interference environment may change and the mobile device may suddenly be immersed in an interference situation in a cell. A base station (e.g., evolved node b (enodeb)) may direct mobile devices to perform within stricter specifications to better handle temporary coexistence issues.

Another application of the principles and advantages discussed herein is in the context of network signaling. For example, the LTE standard provides for multiple network signaling scenarios. Table 1 below includes information about network signaling scenarios that impose strict radiation on specific RF paths and band support in User Equipment (UE) in the LTE cellular communication standard. Such cases include the case of Network Signaling (NS), which may be used for protecting geographic areas of local wireless services, for public safety, for coverage areas geographically occupied by digital television coexistence specifications, and so forth. The frequency bands in table 1 correspond to the E-UTRA (evolved universal terrestrial radio access) operating frequency bands of LTE. Some of these NS cases are used to protect the victim band (victim band). Some other NS cases below relate to spectral masking (spectral mask). The principles and advantages discussed herein may be applied to any of the NS scenarios in table 1 below. The principles and advantages discussed herein may be applied to other NS scenarios that specify more stringent radiation criteria than in the nominal scenario.

TABLE 1 network Signaling scenarios

Fig. 1A is a schematic diagram of a front end structure according to an embodiment. The front-end architecture of fig. 1A may transmit and receive RF signals. The RF signal may have a frequency in the range from about 30kHz to 300GHz, such as, for radio frequency signals in an LTE system, a frequency in the range from about 450MHz to about 4 GHz. In fig. 1A, a dedicated transmission path is provided to cope with a specific radiation specification, such as intermittent radiation and/or relatively rare radiation, and a separate path may be provided for typical operation. The transmit path for typical operation may have better DC performance than a dedicated transmit path for a particular radiation specification. A dedicated path may be switched on to cope with a particular radiation specification while another path may be switched on for typical operation. This may avoid significantly sacrificing performance during typical operation in order to meet certain radiation specifications. In the front-end architecture shown in fig. 1A, the specific radiation specification is the NS _07 specification, while the typical operation is band 13 emission.

The front-end architecture shown in fig. 1A includes a transmit select switch 110, a power amplifier 120, a first duplexer 121, a second duplexer 122, a third duplexer 124, an antenna switch module 130, an antenna 140, and a receive select switch 150. In some other embodiments, the front end structure of fig. 1A and/or any other illustrated embodiment may include more or less elements than those shown.

The transmit select switch 110 may couple the output of the power amplifier 120 to the selected duplexer. The transmission selection switch 110 may be an RF switch. The launch select switch 110 may be a multiple throw switch such as a single pole multiple throw switch as shown. The transmit select switch 110 may couple the output of the power amplifier 120 to a selected one of a plurality of throws. The multiple throws may include a first throw electrically coupled to a first duplexer 121 configured for typical operation, and a second throw electrically coupled to a second duplexer 122 configured to meet a particular radiation specification. The transmit select switch 110 can selectively electrically couple the output of the power amplifier 120 to one of the plurality of throws based at least in part on a signal indicative of an intermittent radiation specification. A signal indicative of the intermittent radiation specification may be received by antenna 140. The transmit select switch 110 may include one or more other throws associated with different frequency bands and/or different operating modes. For example, as shown, the transmit select switch 110 includes a third throw electrically coupled to the third duplexer 124. In fig. 1A, a third duplexer 124 is provided for transmission and reception of band 12.

The second duplexer 122 may have one or more characteristics different from those of the first duplexer 121. For example, the second duplexer 122 may provide a higher out-of-band attenuation in the transmit path than the first duplexer 121. The higher out-of-band attenuation provided by the second duplexer 122 may be symmetric or asymmetric outside the passband. In some examples, increased attenuation on one side of the passband may be sufficient to meet the intermittent radiation specification. For example, the public safety band associated with the NS _07 specification is about 2MHz lower than the transmit band used for band 13. Thus, in such an application, higher out-of-band attenuation may be sufficient at frequencies below the passband of the second duplexer 122, but not at frequencies above the passband. In some other applications, such duplexers may provide higher out-of-band attenuation at frequencies above the passband or higher out-of-band attenuation at frequencies above and below the passband. As another example, the second duplexer 122 may provide higher in-band attenuation than the transmit filter of the first duplexer 121. As shown, a first duplexer 121 provides a transmit filter for typical band 13 transmissions and a second duplexer 122 provides a transmit filter for band 13 transmissions that conform to the NS _07 specification. The transmit filter of the first duplexer 121 and the transmit filter of the second duplexer 122 may be band pass filters having the same pass band, wherein the transmit filter of the second duplexer 122 has a higher out-of-band attenuation than the transmit filter of the first duplexer 121. As described above, the transmission filter of the first duplexer 121 may have different characteristics from the transmission filter of the second duplexer 122.

FIG. 1C is a graph of frequency responses of filters in the two transmit paths of FIG. 1A, according to an embodiment. In fig. 1C, a first curve 180 shows the frequency response of the transmit filter in the second duplexer 122 of fig. 1A, and a second curve 185 shows the frequency response of the transmit filter in the first duplexer 121 of fig. 1A. Both of the transmit filters are bandpass filters having approximately the same passband. Curves 180 and 185 show that the transmit filter in the second duplexer 122 has a higher in-band attenuation than the transmit filter in the first duplexer 121. Therefore, the second duplexer 122 should add more Insertion Loss (IL) than the first duplexer 121. In addition, curves 180 and 185 show that the transmit filter in the second duplexer 122 has a higher out-of-band (OOB) attenuation below the passband than the transmit filter in the first duplexer 121.

Referring back to fig. 1A, the antenna switching module 130 may selectively electrically couple one of the first duplexer 121 or the second duplexer 122 to the antenna 140. In some applications, one or more additional elements may be disposed between the antenna switch module 130 and the antenna 140. The illustrated antenna switch module 130 is configured for bidirectional communication between the selected duplexer and the antenna 140. In a transmit mode, the antenna switch module 130 is configured to provide the RF signal from the selected duplexer to the antenna 140. In the embodiment of fig. 1A, the output of the antenna switch module 130 in the transmit mode provides the selected RF signal to the antenna 140. In a receive mode, the antenna switch module 130 is configured to provide the RF signal from the antenna 140 to the selected duplexer. In the embodiment of fig. 1A, the output of the antenna switch module 130 in the receive mode provides the selected RF signal to the selected duplexer.

The antenna switching module 130 includes switching elements configured to selectively provide the RF signal from the selected transmit path as an output of the switching elements in a transmit mode. As shown, the switching element is a single pole, multiple throw switch. In other embodiments, the switching element may comprise two or more switches. Two or more switches may be configured to transmit signals. The two or more switches may include separate switches for transmitting signals and receiving signals from the antenna 140. The switching element may provide an output to one or more antennas in a transmit mode. For example, as shown in FIG. 1A, the switching element may provide an output to a single antenna 140. In other examples, the switching element may provide an output to an antenna comprising a plurality of antenna elements. According to some embodiments, the switching element may provide RF signals from different paths, such as the band 13 path and the NS _07 band 13 path shown in fig. 1A, to different respective antennas in the transmit mode.

The antenna switching module 130 can selectively electrically couple a selected one of any suitable number of transmit paths to the antenna in the transmit mode. As shown, the antenna switching module 130 may selectively provide an RF signal from one of the first duplexer 121, the second duplexer 122, or the third duplexer 124 to the antenna 140 in a transmit mode. In a first state, the switching element may provide the first RF signal from the first duplexer 121 as a transmit mode output. In a second state, the switching element may provide the second RF signal from the second duplexer 122 as a transmit mode output. In a third state, the switching element may provide the third RF signal from the third duplexer 124 as a transmit mode output.

The antenna switch module 130 may include a switch having at least a first throw electrically coupled to the first duplexer 121 and a second throw electrically coupled to the second duplexer 122. The antenna switching module 130 can electrically couple a selected throw of a plurality of throws including at least a first throw and a second throw to the antenna 140. Thus, antenna switch module 130 may selectively electrically couple a path for typical band 13 operation or a path for NS _07 compatible band 13 operation to antenna 140. The antenna switching module 130 may also selectively electrically couple other paths to the antenna, such as the band 12 path shown in fig. 1A. The switches in the antenna switch module 130 may be multi-throw switches, such as single pole multi-throw switches as shown. The switches in the antenna switch module 130 may be bidirectional switches as shown.

In another embodiment, a switch, such as a single pole double throw switch, may selectively electrically couple the first duplexer 121 or the second duplexer 122 to the antenna switch module.

The front end module shown in fig. 1A includes a receive select switch 150 having a first throw electrically coupled to the receive filter in the first duplexer 121 and a second throw electrically coupled to the receive filter in the second duplexer 122. The receive select switch 150 may include an additional throw that is electrically coupled to other duplexers, such as the third duplexer 124, associated with other operating frequency bands. Alternatively, the reception selection switch may be coupled to the reception path via another switch that may select between coupling the first duplexer 121 or the second duplexer 122 to the reception selection switch.

The encapsulation module may include any of the power amplifier 120, transmit select switch 110, duplexers 121 and 122, and receive select switch 150 of fig. 1A, or any of the functionally similar elements in any of the other embodiments discussed herein. The encapsulation module may include an encapsulation enclosing (enclosure) power amplifier 120, transmit select switch 110, duplexers 121 and 122, and receive select switch 150. Such an encapsulation module may be configured for use in a mobile device, such as a mobile phone (e.g., a smartphone), and the like. In some embodiments, the package module may include a power amplifier 120, a transmit select switch 110, duplexers 121 and 122, a receive select switch 150, and an antenna switch module 130.

FIG. 1B is a schematic diagram of a front end structure according to an embodiment. Fig. 1B illustrates that the antenna switch module 130' may include a multi-pole, multi-throw switching element. As shown, the ANTENNA switch module 130' includes a first blade corresponding to the first ANTENNA PORT1 (ANTENNA PORT 1) and a second blade corresponding to the second ANTENNA PORT 2 (ANTENNA PORT 2). Thus, the antenna switch module 130' may provide RF signals to multiple antennas. The antenna switch module 130' may also receive RF signals from multiple antennas. In an embodiment, the antenna switch module 130' may selectively provide RF signals to the main antenna and the diversity antenna. According to some embodiments, the antenna switch module 130' may provide the RF signal from the selected transmit path to the selected antenna while providing the RF signal received from another antenna to the selected receive path. Although the illustrated antenna switch module 130' includes two blades, the principles and advantages discussed herein may be applied to switching elements having three or more blades. Similarly, such antenna switching elements discussed herein may have any suitable number of throws.

Fig. 2A is a schematic diagram of a front end structure according to another embodiment. In the embodiment of fig. 2A, the respective first duplexer 121 and second duplexer 122 of fig. 1A may be combined into a combined packaged (co-packaged) duplexer 210. The combined package duplexer 210 may reduce cost and size relative to the separate first duplexer 121 and second duplexer 122 of fig. 1A, respectively. The reduction in relative cost and size may result from combined packaging and/or removal of the receive filter. The combined package duplexer 210 may have three input ports TX IN1, TX IN2, and RXIN and three output ports TX OUT1, TX OUT2, and RXOUT. The combined packaged duplexer 210 shown includes two transmit filters and a single receive filter. As shown in fig. 2A, the combined packaged duplexer 210 may include a first transmit filter configured for typical band 13 transmission, a second transmit filter configured for NS _07 mode, and a receive filter. These transmit filters may be bandpass filters having the same passband. The first transmit filter may be configured for relatively low insertion loss in the pass band and may result in relatively high Power Added Efficiency (PAE). The second transmit filter may be configured to meet the NS _07 radiation specification. The second transmit filter may provide more insertion loss and lower efficiency than the first transmit filter, but better frequency attenuation in the NS _07 public safety band. The second transmit filter may provide a higher out-of-band attenuation and/or a higher in-band attenuation than the first transmit filter. As shown in fig. 2A, the receive filter of the combined package duplexer can process a signal received from the antenna 140 using the same filter for both the typical band 13 receive mode and the NS _07 receive mode. Thus, the receive select switch 250 may have one less throw than the receive select switch 150 of fig. 1A.

The antenna switch module 130 shown in fig. 2A has one more throw than the antenna switch module shown in fig. 1A. Three separate traces (trace) or other electrical connections may electrically connect the three throws of the antenna switch module 130 to respective ports of the combined package duplexer 210. The antenna switching module 130 may implement a switch combining function to selectively electrically connect the antenna port to one of the transmit filters and the receive filter. As shown in fig. 2A, the two throws of the antenna switch module 130 may operate simultaneously such that one of the transmit filters of the combined packaged duplexer 210 and the receive filter of the combined packaged duplexer 210 may be coupled to the antenna 140 at the same time. In one state, the antenna switch module 130 of fig. 2A may electrically couple the first transmit filter of the combined package duplexer 210 and the receive filter of the combined package duplexer 210 to the antenna port. In another state, the antenna switching module 130 of fig. 2A may electrically couple the second transmit filter of the combined packaged duplexer 210 and the receive filter of the combined packaged duplexer 210 to the antenna port.

Fig. 2B is a schematic diagram of a front end structure according to an embodiment. Fig. 2B illustrates that the antenna switch module 130' may include a multi-pole, multi-throw switching element and may selectively provide RF signals to the various antenna ports. The features of fig. 2B may be implemented in conjunction with any of the principles and advantages discussed herein.

Fig. 3A is a schematic diagram of a front end structure according to another embodiment. The front-end architecture shown in fig. 3A includes a first power amplifier 310, a second power amplifier 315, a first duplexer 121, a second duplexer 122, a third duplexer 124, a selection switch 320, an antenna switch module 130, an antenna 140, and a receive selection switch 150.

In the embodiment of fig. 3A, two different power amplifiers are implemented. The first power amplifier 310 may be configured for typical operation and the second power amplifier 315 may be configured to meet a particular radiation specification. One of the two power amplifiers may be disabled while the other of the power amplifiers is enabled. These power amplifiers may be configured to amplify RF signals in the same transmit frequency band (e.g., band 13). The first power amplifier 310 may provide an output to the first duplexer 121 without adding insertion loss from the RF switch. The first duplexer 121 may be a relatively low-loss duplexer arranged to meet standard radiation specifications. The transmit path coupled to the second power amplifier 315 may be selected when the signal received from the network indicates that the radio transmitter should meet a particular radiation specification, such as the NS _07 radiation specification. The second power amplifier 315 may be configured to comply with a particular radiation specification. The output of the second power amplifier 315 may be provided to the second duplexer 122 via a selection switch 320. The second duplexer 122 may be switched to meet a particular radiation specification, the second duplexer 122 including an emission filter with higher insertion loss in the pass band and/or higher out-of-band attenuation relative to the emission filter in the first duplexer 121. This may result in less desirable DC current consumption associated with the intermittent signaling specification (e.g., NS _07), but this adverse effect may only occur in the intermittent signaling mode (e.g., NS _07 mode).

The power amplifier may operate in an Envelope Tracking (ET) mode with a modulated supply or an Average Power Tracking (APT) mode with a fixed supply. It may be difficult to configure the power amplifier to perform optimally in both ET mode and APT mode. In one embodiment, two separate power amplifiers may be implemented. A first of these power amplifiers may be configured to achieve maximum power in APT mode for a desired linearity of NS _07 operation. A second of these power amplifiers may be configured to achieve a desired efficiency in ET mode for typical operation. The transmit module may receive a program bit indicating whether to operate in an ET mode or an APT mode. The programming bit may be used to select a first path including a first power amplifier or a second path including a second power amplifier. Since the program bit may be included anyway in some applications, no additional data is needed to select between the first path for typical operation and the second path for the NS _07 operating condition. This may make the implementation of the separate path transparent to the outside of the transmit module.

According to some embodiments, the first power amplifier 310 may be configured to operate in ET mode, while the second power amplifier 315 may be configured to operate in APT mode. In general, the first power amplifier 310 may be configured for relatively high efficiency, while the second power amplifier 315 may be configured for relatively high linearity.

Fig. 3B is a schematic diagram of a front end structure according to an embodiment. Fig. 3B illustrates that the antenna switch module 130' may include a multi-pole, multi-throw switching element and may selectively provide RF signals to the various antenna ports. The features of fig. 3B may be implemented in combination with any of the principles and advantages discussed herein.

Fig. 4A is a schematic diagram of a front end structure according to another embodiment. In the embodiment of fig. 4A, the respective first duplexer 121 and second duplexer 122 of fig. 3 may be combined into a combined package duplexer 210. The combined packaged duplexer 210 may include any combination of the features discussed with reference to fig. 2A and/or 2B. The receive path of the embodiment of fig. 4A may implement any combination of the features of the receive path of fig. 2A and/or 2B, such as the receive select switch 250.

In another embodiment (not shown), the output of the first transmit filter of the combined packaged duplexer 210 of fig. 2A and the output of the second transmit filter of the combined packaged duplexer 210 may be provided to the same transmit input of the antenna switch module 130. According to some such embodiments, power amplifiers 310 and 315 of fig. 4A may be electrically connected to different transmit filters of a combined packaged (co-packed) duplexer 210, and one of power amplifiers 310 and 315 may be deactivated (activated) while the other of these power amplifiers is activated (activated). Thus, one transmit filter of the combined package duplexer 210 receiving the output of the enabled power amplifier may provide an RF output to the transmit input of the antenna switch module 130. This may reduce the number of throws in the switch of the antenna switch module 130 by one throw relative to the embodiment of fig. 2A or the embodiment of fig. 4A.

Fig. 4B is a schematic diagram of a front end structure according to an embodiment. The front-end architecture of fig. 4B is similar to that of fig. 4A, but the antenna switch module 130' includes a multi-pole, multi-throw switching element that can selectively provide RF signals to the various antenna ports. The features of fig. 4B may be implemented in combination with any of the principles and advantages discussed herein.

Fig. 5A-5C are schematic diagrams of front end architectures in which a particular transmit path includes a notch filter, in accordance with various embodiments. In these embodiments, a dedicated transmit path is provided that includes a notch filter to handle intermittent radiation and/or relatively rare radiation, and a separate path is provided for typical operation. Although the front-end architectures shown in fig. 5A through 5C illustrate transmit paths, any of these architectures may also include receive paths. For example, any of the illustrated filters may be implemented in a duplexer and/or a combined package duplexer. Any of the principles and advantages discussed with reference to fig. 5A-5C may be implemented in combination with any of the principles and advantages discussed with reference to any of the other embodiments. Any suitable combination of the features of fig. 5A to 5C may be implemented in combination with each other.

The front-end architecture shown in fig. 5A includes a transmit select switch 110, a power amplifier 120, a notch filter 510, a select switch 520, band pass filters 530 and 540, an antenna switch module 130, and an antenna 140. The transmit select switch 110 and the select switch 520 may selectively turn on the notch filter 510 in the path between the power amplifier 120 and the band pass filter 530.

For selected intermittent radiation and/or relatively rare radiation, notch filter 510 may filter out harmonics of the RF signal provided by power amplifier 120. For example, notch filter 510 may be switched between the output of power amplifier 120 and bandpass filter 530 to filter out the third harmonic of the band 12RF signal provided by power amplifier 120 when the antenna provides a band 4 receive signal to the receive path (not shown). In another example, the notch filter may filter out the second harmonic of the band 13 signal when the GPS frequency band is operating. Notch filter 510 may be configured to filter a particular frequency range for a particular application, for example, by selecting a capacitance value, an inductance value, a resistance value, or any combination thereof, of circuit elements in notch filter 510. Notch filter 510 may be referred to as a band-stop filter.

In some embodiments, band pass filter 540 may have a different pass band than band pass filter 530. Alternatively, the band pass filters 540 may have approximately the same pass band as the band pass filter 530, and the band pass filters may have different filter characteristics. For example, in such an implementation, band pass filter 530 may have a higher in-band attenuation and/or a higher out-of-band attenuation than band pass filter 540.

The front-end architecture shown in fig. 5B includes a transmit select switch 110, a power amplifier 120, a notch filter 510, band pass filters 530, 530', and 540, an antenna switch module 130, and an antenna 140. The transmit select switch 110 may selectively electrically connect the output of the power amplifier 120 to a transmit path including the band pass filter 530' and the notch filter 510 for intermittent radiation and/or relatively rare radiation. The antenna switching module 130 can electrically couple the transmit path including the band pass filter 530' and the notch filter 510 to the antenna 140 for intermittent radiation and/or relatively rare radiation. As shown in fig. 5B, the notch filter 510 may be disposed in the signal path between the bandpass filter 530' and the antenna switching module 130. Alternatively, the band pass filter 530' may be disposed in a signal path between the notch filter 510 and the antenna switching module 130. Bandpass filters 530 and 530' may have the same passband and similar filter characteristics (e.g., in-band attenuation and/or out-of-band attenuation). In some embodiments, band pass filters 530 and 530' may have different filter characteristics.

The front-end architecture shown in fig. 5C includes a first power amplifier 310, a second power amplifier 315, a selection switch 320, a notch filter 510, band pass filters 530 and 530', an antenna switch module 130, and an antenna 140. In this front-end architecture, two different power amplifiers are implemented. One of the two power amplifiers may be disabled while the other of the power amplifiers is enabled. These power amplifiers may be configured to amplify RF signals in the same transmit frequency band. The first power amplifier 310 may provide an output to the band selection filter 530 without adding insertion loss from the RF switch. The selection switch 320 may selectively electrically connect the second power amplifier 315 to a signal path including the notch filter 510 and the band pass filter 530' or a signal path including the band pass filter 540. The signal path with the notch filter 510 and the band pass filter 530' may filter out harmonic frequencies of the RF signal provided by the second power amplifier 315 during the intermittent signaling mode. In an embodiment, the first power amplifier 310 may be configured to operate in an ET mode for typical operation, and the second power amplifier 315 may be configured to operate in an APT mode for an intermittent signaling mode. The separate path for typical operation and the separate path for intermittent signaling mode may be transparent to the outside of the transmit module.

FIG. 6 is a flow diagram of an example process 600 according to an embodiment. Process 600 may include more or fewer operations than those shown. For example, process 600 may be implemented by any of the front end structures discussed herein, such as any of the front end structures of fig. 1A-5C. In block 610, an RF signal may be provided to an antenna. The RF signal may be within a specified frequency band. As an example, the designated frequency band may be the transmit band of band 13, which is from 777MHz to 787 MHz. In block 620, a signal associated with an intermittent radiation specification may be received. The intermittent signaling specification may be, for example, the NS specification from table 1 above. In one embodiment, the intermittent signaling specification may be the NS _07 specification. In response to receiving the signal in block 620, the state of the switch may be changed in block 630 such that a different RF signal is provided to the antenna according to the intermittent signaling specification. In block 630, one or more switches discussed herein (such as one or more of the transmit select switch 110, the antenna switch module 130 or 130', and the receive select switches 150 and/or 250) may change state. Accordingly, the plurality of switches may change state in block 630. The different RF signal may be within the same designated frequency band as the RF signal provided in block 610. The processing may include generating the different RF signals such that the different RF signals have a higher linearity than the RF signals. Alternatively or additionally, the processing may include generating the different RF signals such that the different RF signals have a higher attenuation outside of a specified frequency band than the RF signals.

Fig. 7A and 7B are schematic diagrams of package modules 700 and 700', respectively, according to some embodiments. These modules may include one or more dies and/or other components integrated within a package. These modules may include a package substrate, such as a laminate substrate, configured to house a plurality of components. The module may include contacts, such as pins, for electrical connection to other electronic components.

As shown in fig. 7A, the package module 700 may include one or more power amplifier die 710, one or more filter die 720, and one or more switch die 730. Power amplifier die 710 may include any of the power amplifiers discussed herein. In an embodiment, a single power amplifier die 710 may include the power amplifiers shown in any of the front end architectures discussed herein. One or more filter dies 720 can include any of the filters and/or duplexers discussed herein. For example, the filter wafer 720 may include surface acoustic wave filters and/or bulk acoustic wave filters. According to some embodiments, separate filter dies may implement separate duplexers. In an embodiment, one filter die may implement the combined package duplexer 210, while another filter die may implement another duplexer. The switch die 730 may implement any of the switches discussed herein.

As shown in fig. 7B, the package module 700' may include one or more filter dies 720 and one or more switch dies 730. In such embodiments, the package module 700' may include one or more contacts to provide electrical connections to one or more power amplifiers.

Fig. 8 is a schematic block diagram of one example of a wireless or mobile device 811 that may include one or more power amplifiers and one or more antenna switch modules. The wireless device 811 may include transmit and/or receive paths that implement one or more features of the present application. For example, power amplifier 817 of fig. 8 may correspond to any of the power amplifiers discussed with reference to fig. 1A-7. Similarly, the antenna switch module 130 and the antenna 140 of fig. 8 may correspond to any of the elements in the antenna switch module and/or antenna, respectively, discussed herein. Additional elements, such as any of the duplexers discussed herein, may be disposed between the output of any of the power amplifiers 817 of fig. 8 and the antenna switch module 130.

The example wireless device 811 depicted in fig. 8 may represent a multi-frequency and/or multi-mode device, such as a multi-frequency/multi-mode mobile phone. As an example, wireless device 811 may communicate in accordance with Long Term Evolution (LTE). In this example, the wireless device may be configured to operate on one or more frequency bands defined by the LTE standard. The wireless device 811 may alternatively or additionally be configured to communicate in accordance with one or more other communication standards including, but not limited to, one or more of the Wi-Fi standard, the 3G standard, the 4G standard, or the LTE advanced standard. The transmit and/or receive paths of the present application may be implemented within, for example, a mobile device implementing any combination of the aforementioned example communication standards.

As shown, the wireless device 811 may include an antenna switch module 130, a transceiver 813, an antenna 140, a power amplifier 817, a control component 818, a computer-readable storage medium 819, a processor 820, and a battery 821.

Transceiver 813 may generate RF signals for transmission via antenna 140. In addition, transceiver 813 can receive incoming RF signals from antenna 140. In some implementations, the wireless device 811 can include multiple antennas, such as a main antenna and a diversity antenna. It will be appreciated that various functions associated with the transmission and reception of RF signals may be implemented by one or more components collectively represented in fig. 8 as transceiver 813. For example, a single component may be configured to provide both transmit and receive functionality. In another example, the transmit function and the receive function may also be provided by separate components.

In fig. 8, one or more output signals from transceiver 813 are depicted as being provided to antenna 140 via one or more transmit paths 815. In the illustrated example, the different transmit paths 815 may represent output paths associated with different frequency bands and/or different power outputs. For example, the two different paths shown may represent two of the different transmit paths of any of the front-end architectures discussed with reference to fig. 3A through 4B or 5C. As another example, a separate transmit path may be provided from the output of the power amplifier 817 in accordance with any of the front end architectures discussed with reference to fig. 1A-2B, 5A or 5B. The transmit path 815 may be associated with different transmit modes (e.g., a nominal mode and an intermittent signaling mode). Other transmit paths 815 may be associated with different power modes (e.g., a high power mode and a low power mode) and/or paths associated with different transmit frequency bands. The transmit path 815 may include one or more power amplifiers 817 to help boost RF signals having relatively low power to higher power suitable for transmission. Power amplifier 817 may include, for example, power amplifier 120 or power amplifiers 310 and 315 discussed above. Although fig. 8 illustrates a configuration using two transmit paths 815, the wireless device 811 may be adapted to include more or fewer transmit paths 815.

In fig. 8, one or more detected signals from antenna 140 are depicted as being provided to transceiver 813 via one or more receive paths 816. In the illustrated example, the different receive paths 816 may represent paths associated with different signaling patterns and/or different receive frequency bands. Although fig. 8 illustrates a configuration using four receive paths 816, the wireless device 811 may be adapted to include more or fewer receive paths 816.

To facilitate switching between receive and/or transmit paths, an antenna switch module 130 may be included, and the antenna switch module 130 may be used to selectively electrically connect the antenna 140 to a selected transmit path or receive path. Thus, the antenna switch module 130 may provide a number of switching functions associated with the operation of the wireless device 811. The antenna switch module 130 may include a multi-throw switch configured to provide functionality associated with, for example, switching between different frequency bands, switching between different modes, switching between transmit and receive modes, or any combination thereof.

Fig. 8 illustrates that in some embodiments, a control component 818 can be provided to control various control functions associated with the operation of the antenna switch module 130 and/or other operational components. For example, the control component 818 can facilitate providing a control signal to the antenna switch module 130 to select a particular transmit path or receive path. For example, the control component may generate the selection signal for the antenna switching module 130 based at least in part on a signal associated with an intermittent signaling specification received by the wireless device 811.

In some embodiments, the processor 820 may be configured to facilitate various processing on the wireless device 811. The processor 820 may be, for example, a general-purpose processor or a special-purpose processor. In some implementations, the wireless device 811 may include a computer-readable memory 819 that may store computer program instructions that may be provided to the processor 820 and executed by the processor 820.

The battery 821 may be any suitable battery for use in the wireless device 811, including, for example, a lithium ion battery.

Although certain embodiments are discussed herein with reference to NS _07 mode and typical band 13 mode for purposes of illustration, it is to be understood that the principles and advantages discussed herein may be applied to any suitable implementation having intermittent specifications and typical specifications with different design constraints. For example, any of the principles and advantages discussed herein may be applied to any other NS _ xy scenario, coexistence requirements of radiation when simultaneous Wi-Fi operation occurs in a handset, and the like.

Some of the embodiments described above have provided examples relating to power amplifiers and/or mobile devices. However, the principles and advantages of the embodiments may also be applied to any other system or apparatus, such as any uplink cellular device, that may benefit from any of the circuits described herein. The teachings herein are applicable to a variety of power amplifier systems including systems having multiple power amplifiers, including, for example, multi-frequency and/or multi-mode power amplifier systems. The teachings described herein may be applied to various power amplifier structures, such as multi-stage power amplifiers and power amplifiers employing various transistor structures. The power amplifier transistors discussed herein may be, for example, gallium arsenide (GaAs) transistors, silicon germanium (SiGe) transistors, or silicon transistors. The power amplifiers discussed herein may be implemented by field effect transistors and/or bipolar transistors such as heterojunction bipolar transistors.

Aspects of the present application may be implemented in various electronic devices. Examples of electronic devices may include, but are not limited to, consumer electronics, components of consumer electronics, electronic test equipment, and the like. Examples of electronic devices may include, but are not limited to, mobile phones such as smart phones, telephones, televisions, computer displays, computers, modems, handheld computers, notebook computers, tablet computers, Personal Digital Assistants (PDAs), microwave ovens, refrigerators, in-vehicle electronic systems such as automotive electronic systems, stereos, DVD players, CD players, digital music players such as MP3 players, radios, video cameras, digital cameras, portable memory chips, washing machines, dryers, washer/dryers, copiers, facsimile machines, scanners, multifunction peripherals, watches, clocks, and the like. Further, the electronic device may include unfinished products.

Throughout the specification and claims, unless the context clearly requires otherwise, the words "comprise", "comprising", "contain", "having", "including", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, that is, in the sense of "including but not limited to". The term "coupled," as used generally herein, means that two or more elements may be connected directly or by way of one or more intermediate elements. Likewise, the word "connected," as generally used herein, means that two or more elements may be connected directly or 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 which use the singular or plural number may also include the plural or singular number respectively. The word "or," when appropriate, referring to a list of two or more items, is intended to cover 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.

Furthermore, unless explicitly stated otherwise, or otherwise understood in the context of usage, conditional words such as "may", "like (e.g)", "for example", "such as" and the like, are generally intended to convey that certain embodiments include certain features, elements and/or states, while other embodiments do not. Thus, such conditional language is not generally intended to imply: the features, elements, and/or states may be required in any suitable order for one or more embodiments; or one or more embodiments may include logic to determine whether such features, elements, and/or states are included or are to be performed in any particular embodiment, with or without programmer input or prompting.

While certain embodiments of the present invention have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the application. Indeed, the novel apparatus, methods, and systems described herein may be embodied in various 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 application. For example, while blocks are presented in a given setting, alternative embodiments may perform similar functions 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 application.

Claims (23)

1. An apparatus, comprising:

a first transmit path configured to provide a first Radio Frequency (RF) signal according to a nominal specification, the first RF signal being within a transmit frequency band;

a second transmit path configured to provide a second RF signal according to an intermittent specification, the second RF signal being within a same transmit frequency band as the first RF signal; and

a switch element coupled to both the first transmit path and the second transmit path, the switch element configured to provide the first RF signal as a transmit mode output in a first state and the second RF signal as the transmit mode output in a second state.

2. The apparatus of claim 1, wherein the first transmit path comprises a first transmit filter and the second transmit path comprises a second transmit filter, the first transmit filter and the second transmit filter having approximately the same passband.

3. The apparatus of claim 2, wherein the second transmit filter has a higher out-of-band attenuation than the first transmit filter.

4. The apparatus of claim 3, wherein the second transmit filter has a higher in-band attenuation than the first transmit filter.

5. The apparatus of claim 1, wherein the second transmit path comprises a band pass filter and a notch filter.

6. The apparatus of claim 1, wherein the first transmit path is associated with higher power added efficiency than the second transmit path, and the second transmit path is associated with higher linearity than the first transmit path.

7. The apparatus of claim 1, further comprising: a first power amplifier associated with the first transmit path and configured to operate in an envelope tracking mode; and a second power amplifier associated with the second transmit path and configured to operate in an average power tracking mode.

8. The apparatus of claim 1, wherein the switching element comprises a multi-throw radio frequency switch comprising at least a first throw and a second throw, the first throw electrically coupled to the first transmit path and the second throw electrically coupled to the second transmit path.

9. The apparatus of claim 1, wherein the switching element is configured to selectively electrically couple one of the first, second, or third transmit paths to a transmit mode output of the switching element.

10. The apparatus of claim 1, wherein the first transmit path has a lower insertion loss than the second transmit path.

11. The apparatus of claim 1, wherein a transmit mode output of the switching element is electrically coupled to an antenna port.

12. The apparatus of claim 1, wherein the intermittent specification is the NS _07 specification and the same transmission band is from 777MHz to 787 MHz.

13. An apparatus, comprising:

a first transmit filter having a passband;

a second transmit filter having approximately the same passband as the first transmit filter, the second transmit filter configured to provide a higher out-of-band attenuation than the first transmit filter; and

a switching element electrically coupled to the first transmit filter and the second transmit filter.

14. The apparatus of claim 13, wherein the radio frequency switching element has: a first throw configured to receive a first RF signal from the first transmit filter; and a second throw configured to receive a second RF signal from the second transmit filter.

15. The apparatus of claim 14, wherein the switching element is configured to selectively electrically couple the second throw to an antenna port based at least in part on a signal indicative of an intermittent signaling mode.

16. The apparatus of claim 13, further comprising an antenna, the switching element electrically coupled between the antenna and the first transmit filter, and the switching element electrically coupled between the antenna and the second transmit filter.

17. The apparatus of claim 13, wherein the first transmit filter and the second transmit filter are included in a combined packaged duplexer, the combined packaged duplexer including a single receive filter.

18. The apparatus of claim 17, wherein a switching element is configured to electrically couple an antenna port to the single receive filter and the first transmit filter in a first state and to electrically couple the antenna port to the single receive filter and the second transmit filter in a second state.

19. The apparatus of claim 13, further comprising a first power amplifier in communication with the first transmit filter and a second power amplifier in communication with the second transmit filter.

20. The apparatus of claim 13, wherein the second filter is configured to provide higher in-band attenuation than the first filter.

21. The apparatus of claim 13, wherein the out-of-band attenuation of the second filter is asymmetric with respect to the passband.

22. An electronically-implemented method, comprising:

providing a Radio Frequency (RF) signal to an antenna, the RF signal being within a specified frequency band;

receiving a signal associated with an intermittent radiation specification; and

in response to the receiving, changing a state of a switch to cause a different RF signal according to the intermittent radiation specification to be provided to the antenna, the different RF signal being within the specified frequency band.

23. The method of claim 22, further comprising: generating the different RF signal such that the different RF signal has a higher linearity than the RF signal.