Radio-frequency circuit and communication device

The present application is based on and claims priority of Japanese Patent Application No. 2019-101502 filed on May 30, 2019. The entire disclosure of the above-identified application, including the specification, drawings and claims is incorporated herein by reference in its entirety.

The present disclosure relates to a radio-frequency circuit and a communication device.

In recent communication services, there is a demand for radio-frequency front-end circuits that propagate radio-frequency signals of a plurality of communication bands with a high quality for high-volume and high-speed communication.

Patent Literature (PTL) 1 discloses a radio-frequency front-end circuit capable of multiplexing radio-frequency signals of a plurality of communication bands with low loss. PTL 1 (FIG. 4), for example, discloses LNA 31 that is capable of amplifying radio-frequency signals of communication band Bp and communication band Bd. Switch 22B switches between the connection between the signal path of communication band Bp and LNA 31 and the connection between the signal path of communication band Bd and LNA 31.

PTL 1: Japanese Unexamined Patent Application Publication No. 2018-19392

In recent years, following the change of communication bands to wide bands and high frequencies, the bandwidths and frequency bands of communication bands to be handled are becoming diversified. On the other hand, as the bandwidths and frequency bands for which a single low-noise amplifier (LNA) has to perform amplification become extensive, amplification performances, such as a gain and distortion characteristics, and a power consumption deteriorate.

Based on t the above viewpoint, in the radio-frequency front-end circuit disclosed in Patent Literature 1, even when the bandwidths and frequency bands for which the single LNA has to perform amplification become extensive, ensuring high amplification performances for all of the plurality of communication bands is desired.

In view of this, the present disclosure provides a radio-frequency circuit and a communication device that are capable of amplifying, with high amplification performances, radio-frequency signals of a plurality of communication bands.

A radio-frequency circuit according to an aspect of the present disclosure includes: a first switch including a common terminal, a first selection terminal, and a second selection terminal, the first switch configured to switch between connecting the common terminal and the first selection terminal and connecting the common terminal and the second selection terminal; a first low-noise amplifier including an input terminal connected to the first selection terminal; and a second low-noise amplifier including an input terminal connected to the second selection terminal, wherein a frequency band in which the first low-noise amplifier amplifies a radio-frequency signal by at least a predetermined gain includes a frequency band in which the second low-noise amplifier amplifies a radio-frequency signal by at least a predetermined gain.

The present disclosure can provide radio-frequency circuits and communication devices that amplify, with high amplification performances, radio-frequency signals of a plurality of communication bands.

These and other advantages and features will become apparent from the following description thereof taken in conjunction with the accompanying Drawings, by way of non-limiting examples of embodiments disclosed herein.

FIG. 1 is an example of a circuit configuration diagram of a radio-frequency circuit and a communication device according to an embodiment.

FIG. 2A illustrates an example of a circuit configuration diagram of a first low-noise amplifier, a second low noise amplifier, and a first switch included in the radio-frequency circuit according to the embodiment.

FIG. 2B illustrates gain-frequency characteristics of the first low-noise amplifier and the second low-noise amplifier.

FIG. 3A is an example of a diagram illustrating an example of a circuit configuration of the first low-noise amplifier and the second low-noise amplifier according to the embodiment.

FIG. 3BA is an outline diagram illustrating an example of a circuit configuration.

FIG. 3BB illustrates example gain-frequency characteristics of a second low-noise amplifier according to Variation embodiment 1 of the embodiment.

FIG. 3C is an example of a circuit configuration diagram of a radio-frequency circuit according to Variation embodiment 2 of the embodiment.

FIG. 4A is a diagram illustrating an example of a circuit configuration of a filter included in a multiplexer according to the embodiment.

FIG. 4B is a diagram illustrating an example of a circuit configuration of a first filter according to the embodiment.

FIG. 5 is a circuit configuration diagram of a radio-frequency circuit and an antenna element according to Variation embodiment 3 of the embodiment.

Hereinafter, exemplary embodiments of the present disclosure will be described in detail with reference to the drawings. It should be noted that each of the subsequently described exemplary embodiments and variations shows a generic or a specific example. The numerical values, shapes, materials, elements, the arrangement and connection of the elements, and others indicated in the following exemplary embodiments and variations are mere examples, and therefore are not intended to limit the present disclosure. Among the elements described in the following exemplary embodiments and variations, elements not recited in any one of the independent claims are described as optional elements. In addition, the sizes of the elements and the ratio of the sizes illustrated in the drawings are not necessarily accurate.

1. Configuration of Radio-Frequency Circuit 1 and Communication Device 5

FIG. 1 is an example of a circuit configuration diagram of radio-frequency circuit 1 and communication device 5 according to the embodiment. As illustrated in the figure, communication device 5 includes radio-frequency circuit 1 , antenna element 2 , RF signal processing circuit (RFIC) 3 , and baseband signal processing circuit (BBIC) 4 .

Radio-frequency circuit 1 includes common terminal 100 , multiplexer 11 , filters 12 A and 12 B, switch 13 , low-noise amplifiers 21 A, 21 B 1 and 21 B 2 , reception output terminals 110 A, 110 B 1 , and 110 B 2 .

Switch 13 , which is an example of a first switch, includes common terminal 13 a , selection terminal 13 b 1 (a first selection terminal) and selection terminal 13 b 2 (a second selection terminal) and switches between the connection between common terminal 13 a and selection terminal 13 b 1 and the connection between common terminal 13 a and selection terminal 13 b 2 . Switch 13 is for example a single pole, double throw (SPDT) switch.

Low-noise amplifier 21 B 1 , which is an example of a first low-noise amplifier, includes an input terminal (a first input terminal) connected to selection terminal 13 b 1 and an output terminal (a first output terminal) connected to reception output terminal 110 B 1 and amplifies a radio-frequency signal input via common terminal 13 a and selection terminal 13 b 1 and outputs the amplified radio-frequency signal from reception output terminal 110 B 1 to RFIC 3 . Low-noise amplifier 21 B 1 is capable of amplifying radio-frequency signals of communication band B 1 , for example.

Low-noise amplifier 21 B 2 , which is an example of a second low-noise amplifier, includes an input terminal (a second input terminal) connected to selection terminal 13 b 2 and an output terminal (a second output terminal) connected to reception output terminal 110 B 2 and amplifies a radio-frequency signal input via common terminal 13 a and selection terminal 13 b 2 and outputs the amplified radio-frequency signal from reception output terminal 110 B 2 to RFIC 3 . Low-noise amplifier 21 B 2 is capable of amplifying radio-frequency signals of communication band B 2 , for example.

Here, the frequency band in which low-noise amplifier 21 B 1 amplifies a radio-frequency signal by at least a predetermined gain includes the frequency band in which low-noise amplifier 21 B 2 amplifies a radio-frequency signal by at least the predetermined gain. In one embodiment, communication band B 1 includes communication band B 2 .

According to this configuration, the frequency band in which at least the predetermined gain is achieved is narrower for low-noise amplifier 21 B 2 than for low-noise amplifier 21 B 1 , and thus low-noise amplifier 21 B 2 is more capable of enhancing amplification performances such as a maximum gain, a power consumption, and a signal distortion. Therefore, it is possible to obtain high amplification performances, such as a high gain, a low power consumption, and a low signal distortion in comparison to, for example, the case where the single low-noise amplifier 21 B 1 amplifies a radio-frequency signal of communication band B 1 corresponding to the frequency band in which low-noise amplifier 21 B 1 is capable of amplifying by at least a predetermined gain and a radio-frequency signal of communication band B 2 corresponding to the frequency band in which low-noise amplifier 21 B 2 is capable of amplifying by at least a predetermined gain.

Low-noise amplifier 21 A includes an input terminal connected to terminal 160 A and an output terminal connected to reception output terminal 110 A, and amplifies a radio-frequency signal input via terminal 160 A and outputs the amplified radio-frequency signal from the output terminal to reception output terminal 110 A. Low-noise amplifier 21 A is capable of amplifying radio-frequency signals of communication band A, for example. It should be noted that the frequencies of communication band A and communication band B 1 do not overlap each other, and the frequencies of communication band A and communication band B 2 do not overlap each other.

Filter 12 B, which is an example of a first filter, is a radio-frequency filter that includes an output terminal connected to common terminal 13 a of switch 13 and an input terminal connected to connection node n 2 .

According to this configuration, unnecessary waves of radio-frequency signals to be input to low-noise amplifiers 21 B 1 and 21 B 2 can be suppressed upstream of low-noise amplifiers 21 B 1 and 21 B 2 , and thus the S/N ratio of the radio-frequency signals output from low-noise amplifiers 21 B 1 and 21 B 2 improves.

Filter 12 A is a radio-frequency filter that includes an output terminal connected to terminal 160 A and an input terminal connected to connection node n 1 .

According to this configuration, unnecessary waves of radio-frequency signals to be input to low-noise amplifier 21 A can be suppressed upstream of low-noise amplifier 21 A, and thus the S/N ratio of the radio-frequency signals output from low-noise amplifier 21 A improves.

Multiplexer 11 includes filters 11 A, 11 B, 11 C, and 11 D. It should be noted that the respective passbands of filters 11 A to 11 D do not overlap one another.

Filter 11 A is a radio-frequency filter that includes an input terminal connected to common terminal 100 and an output terminal connected to connection node n 1 . Filter 11 B is a radio-frequency filter that includes an input terminal connected to common terminal 100 and an output terminal connected to connection node n 2 . Filter 11 C is a radio-frequency filter that includes an input terminal connected to common terminal 100 . Filter 11 D is a radio-frequency filter that includes an input terminal connected to common terminal 100 .

It should be noted that it is sufficient that multiplexer 11 be configured to multiplex radio-frequency signals of at least two different frequency bands. From this viewpoint, it is sufficient that the number of radio-frequency filters included in multiplexer 11 be two or more.

It should be noted that although the circuit elements to which the output terminal of filter 11 C and the output terminal of filter 11 D are connected have been omitted in FIG. 1 , each may be further connected to a radio-frequency filter.

It should be noted that switch 13 and low-noise amplifiers 21 B 1 and 21 B 2 may be realized as radio-frequency module 10 composed of a single chip semiconductor integrated circuit (IC). In addition, the semiconductor IC may include low-noise amplifier 21 A.

The semiconductor IC includes, for example, a complementary metal oxide semiconductor (CMOS). Specifically, the semiconductor IC is configured using a silicon on insulator (SOI) structure. According to this, the semiconductor IC can be manufactured at low cost. It should be noted that the semiconductor IC may include at least one of GaAs, SiGe, or GaN. According to this, radio-frequency signals having high quality amplification performance and noise performance can be output.

At least one of filters 11 A to 11 D may be an acoustic wave filter that includes an acoustic wave resonator. The acoustic wave resonator is, for example, an acoustic wave resonator that uses a surface acoustic wave (SAW) or an acoustic wave resonator that uses a bulk acoustic wave (BAW). Furthermore, at least one of filter 12 A or 12 B may be an LC filter including at least one of an inductor or a capacitor.

When communication band A and communication bands B 1 and B 2 are wide bands and the frequency interval (frequency gap) between neighboring communication bands is narrow, configuring filters 11 A to 11 D disposed upstream using LC filters causes the problem of increased radio-frequency signal propagation loss in multiplexer 11 . In contrast, by configuring multiplexer 11 using acoustic wave filters that cause high attenuation of the attenuation band in the passband vicinity, the radio-frequency signals of the respective communication bands can be multiplexed with high isolation even when the respective communication bands are relatively close. Furthermore, although the amount of attenuation decreases in bands which are far from the passband in acoustic wave filters, since LC filters capable of ensuring stable attenuation over a wide band in bands that are far from the passband are used in filters 12 A and 12 B disposed downstream, it is possible to cause high attenuation in bands that are far from the passband. Therefore, the radio-frequency signals of a plurality of communication bands can be multiplexed with high isolation and low loss.

It should be noted that ratio-frequency circuit 1 according to this embodiment is a reception circuit that propagates radio-frequency signals received by antenna element 2 and outputs the radio-frequency signals to RFIC 3 , but may be a transceiver circuit that further includes a transmission circuit.

Furthermore, radio-frequency circuit 1 need not include common terminal 100 , multiplexer 11 , filters 12 A and 12 B, and low-noise amplifier 21 A.

Hereinafter, elements included in communication device 5 other than radio-frequency circuit 1 will be described.

Antenna element 2 is connected to common terminal 100 of radio-frequency circuit 1 and receives radio-frequency signals. Furthermore, when radio-frequency circuit 1 includes a transmission circuit, antenna element 2 may emit a radio-frequency signal output from RFIC 3 and propagated in radio-frequency circuit 1 .

RFIC 3 is an RF signal processing circuit that processes a radio-frequency signal output from radio-frequency circuit 1 via reception output terminal 110 A, 110 B 1 , and 110 B 2 . Furthermore, when radio-frequency circuit 1 includes a transmission circuit, RFIC 3 performs, by upconversion, etc., signal processing on a transmission signal input from BBIC 4 , and outputs the radio-frequency signal generated by the signal processing to radio-frequency circuit 1 . Furthermore, RFIC 3 includes a controller that outputs a control signal for switching the connection state of switch 13 , based on the communication band to be used. It should be noted that the controller may be provided outside of RFIC 3 , and may be provided, for example, in radio-frequency circuit 1 or BBIC 4 .

BBIC 4 is a circuit that performs signal processing using an intermediate frequency band having a lower frequency than a radio-frequency signal propagating in radio-frequency circuit 1 . The signal processed by BBIC 4 is, for example, used as image signals for image display or as sound signals for telephone conversation via a speaker.

2. Amplification Characteristics of Low-Noise Amplifiers 21 B 1 and 21 B 2 According to the Embodiment

FIG. 2A illustrates an example of a circuit configuration diagram of low-noise amplifiers 21 B 1 and 21 B 2 and switch 13 included in radio-frequency circuit 1 according to the embodiment, and an outline diagram illustrating gain-frequency characteristics of low-noise amplifiers 21 B 1 and 21 B 2 . FIG. 2A illustrates a circuit configuration of switch 13 and low-noise amplifiers 21 B 1 and 21 B 2 included in radio-frequency circuit 1 . Furthermore, FIG. 2A illustrates the gain-frequency characteristics of low-noise amplifier 21 B 1 (solid line) and the gain-frequency characteristics of low-noise amplifier 21 B 2 (broken line).

As illustrated in FIG. 2B , the frequency band in which low-noise amplifier 21 B 1 can amplify by at least a predetermined gain includes the frequency band in which low-noise amplifier 21 B 2 amplifies radio-frequency signals by the predetermined gain. More specifically, low-noise amplifier 21 B 1 has, as a possible amplification band, a band (first frequency band) in which low-noise amplifier 21 B 1 is capable of amplifying radio-frequency signals by at least a gain (15 dB) that is smaller than the maximum gain of low-noise amplifier 21 B 1 by a predetermined value (for example, 3 dB). Furthermore, low-noise amplifier 21 B 2 has, as a possible amplification band, a band (second frequency band) in which low-noise amplifier 21 B 2 is capable of amplifying a radio-frequency signal by at least a gain (18 dB) that is smaller than the maximum gain of low-noise amplifier 21 B 2 by a predetermined value (for example, 3 dB). Here, the first frequency band of low-noise amplifier 21 B 1 corresponds to communication band B 1 and the second frequency band of low-noise amplifier 21 B 2 corresponds to communication band B 2 , and the first frequency band includes the second frequency band. In this case, since the frequency band for which low-noise amplifier 21 B 2 needs to perform amplification is narrower than that of low-noise amplifier 21 B 1 , low-noise amplifier 21 B 2 is more capable of enhancing amplification performance such as maximum gain, power consumption, and signal distortion.

It should be noted that, in this embodiment, “the first frequency band includes the second frequency band” is defined as a state corresponding to any one of equations (1) to (3) below. It should be noted that the low-end frequency of the first frequency band is denoted as fL1, the high-end frequency of the first frequency band is denoted as fH1, the low-end frequency of the second frequency band is denoted as fL2, the high-end frequency of the second frequency band is denoted as fH2.

(1) f L1 <f L2 and f H2 <f H1

(2) f L1 =f L2 and f H2 <f H1

(3) f L1 <f L2 and f H2 =f H1

A conventional radio-frequency circuit has a configuration in which a radio-frequency signal of communication band B 1 and a radio-frequency signal of communication band B 2 are amplified by a single low-noise amplifier 21 B 1 . As such, compared to when the radio-frequency signal of communication band B 2 is amplified by low-noise amplifier 21 B 2 , when the radio-frequency signal of communication band B 2 is amplified by low-noise amplifier 21 B 1 , amplification performance deteriorates because maximum gain becomes lower, power consumption increases, and signal distortion increases.

In contrast, with radio-frequency circuit 1 according to this embodiment, the radio-frequency signal of communication band B 1 and the radio-frequency signal of communication band B 2 whose frequencies are in an inclusion relation are amplified by being divided between low-noise amplifier 21 B 1 and low-noise amplifier 21 B 2 according to the frequency band of the communication band. For this reason, when amplifying a radio-frequency signal of communication band B 2 , amplification performance such as high maximum gain, low power consumption, and low signal distortion can be ensured compared to the conventional radio-frequency circuit.

For example, in the fifth-generation mobile communication system (5G), the communication band is being widened compared to that in the fourth-generation mobile communication system (4G). In the initial stages of introduction of 5G, there is a demand for radio-frequency circuits capable of handling both 4G and 5G. In this case, a radio-frequency circuit that simultaneously transfers 4G-long term evolution (LTE) radio-frequency signals and 5G-new radio (NR) radio-frequency signals becomes necessary. For this reason, in radio-frequency circuit 1 according to this embodiment, a 5G-NR communication band is applied as communication band B 1 and a 4G-LTE communication band is applied as communication band B 1 .

For example, n 77 (3300 MHz to 4200 MHz) of 5G-NR may be applied as communication band B 1 , and at least one of B 42 (3400 MHz to 3600 MHz), B 43 (3600 MHz to 3800 MHz), B 48 (3550 MHz to 3700 MHz), or B 49 (3550 MHz to 3700 MHz) of 4G-LTE may be applied as communication band B 2 .

In the case of the above-mentioned conventional radio-frequency circuit, when the radio-frequency signal of the 4G-LTE communication band having a relatively narrow band is amplified by low-noise amplifier 21 B 1 that has amplification characteristics for a wide band, the maximum gain becomes lower, power consumption increases, and signal distortion increases.

In contrast, with radio-frequency circuit 1 according to this embodiment, the radio-frequency signal of the 5G-NR communication band and the radio-frequency signal of the 4G-LTE communication band whose frequencies are in an inclusion relation are amplified by being divided between low-noise amplifier 21 B 1 and low-noise amplifier 21 B 2 according to the frequency band of the communication band. For this reason, when amplifying a radio-frequency signal of a 4G-LTE communication band which is a relatively narrow band, amplification performance such as high maximum gain, low power consumption, and low signal distortion can be ensured compared to the conventional radio-frequency circuit.

Furthermore, in radio-frequency circuit 1 according to this embodiment, a 5G-NR or 4G-LTE communication band may be applied as communication band B 1 and a wireless local area network (WLAN with a frequency range from 5.15 GHz to 7.125 GHz band, hereinafter referred to as a WLAN of at least 5 GHz) may be applied as communication band B 2 . For example, communication band B 1 is B 46 with a frequency range from 5.15 GHz to 5.925 GHz, of NR-U, and communication band B 2 is a WLAN of at least 5 GHz. It should be noted that NR-U is a 5G-NR band of at least 5 GHz in 3GPP, and corresponds to the U-NII communication band within the unlicensed band of the Federal Communication Commission (FCC).

Furthermore, in radio-frequency circuit 1 according to this embodiment, a WLAN of at least 5 GHz may be applied as communication band B 1 and a 5G-NR or 4G-LTE communication band may be applied as communication band B 2 . For example, communication band B 1 is a WLAN (5.15 GHz to 7.125 GHz band) and communication band B 2 is B 46 of NR-U.

Furthermore, in radio-frequency circuit 1 according to this embodiment, a 5G-NR communication band may be applied as communication band B 1 and a 5G-NR communication band may be applied as communication band B 2 . For example, communication band B 1 is n 77 of 5G-NR, and communication band B 2 is n 78 (3300 MHz to 3800 MHz) of 5G-NR. Furthermore, for example, communication band B 1 is n 257 (26.5 GHz to 29.5 GHz) of 5G-NR, and communication band B 2 is n 261 (27.5 GHz to 28.35 GHz) of 5G-NR.

It should be noted that a signal modulation scheme for 4G-LTE is, for example, single carrier-frequency division multiple access (SC-FDMA) and a signal modulation scheme for 5G-NR is, for example, cyclic prefix-orthogonal frequency division multiplexing (CP-OFDM). Furthermore, a signal modulation scheme for WLAN is, for example, OFDM. In other words, the signal modulation scheme for 4G-LTE and the signal modulation scheme for 5G-NR, and the signal modulation scheme for WLAN are different from each other.

It should be noted that, in radio-frequency circuit 1 according to this embodiment, n 79 (4400 MHz to 5000 MHz) of 5G-NR may be applied as communication band A, n 77 of 5G-NR may be applied as communication band B 1 , and any one of n 78 of 5G-NR, B 42 , B 43 , B 48 , and B 49 of 4G-LTE may be applied as communication band B 2 .

According to the above-described configuration, radio-frequency circuit 1 is capable of transferring a 5G-NR radio-frequency signal and a 4G-LTE radio-frequency signal.

For example, by alternately switching between connecting common terminal 13 a and selection terminal 13 b 1 and connecting common terminal 13 a and selection terminal 13 b 2 by switch 13 , the radio-frequency signal to be output from one of low-noise amplifier 21 B 1 and low-noise amplifier 21 B 2 can be propagated with low loss, without leaking into the other of low-noise amplifier 21 B 1 and low-noise amplifier 21 B 2 . Furthermore, a radio-frequency signal of communication band A and a radio-frequency signal of communication band B 1 can be simultaneously received, and a radio-frequency signal of communication band A and a radio-frequency signal of communication band B 2 can be simultaneously received.

For example, by applying B 1 (reception band: 2110 MHz to 2170 MHz) of 4G-LTE as communication band A, simultaneous reception for B 1 of 4G-LTE and n 77 of 5G-NR and simultaneous reception of B 1 of 4G-LTE and B 42 of 4G-LTE can be alternately executed.

Furthermore, for example, by simultaneously executing connection between common terminal 13 a and selection terminal 13 b 1 and connection between common terminal 13 a and selection terminal 13 b 2 by switch 13 , the radio-frequency signal amplified by low-noise amplifier 21 B 1 and the radio-frequency signal amplified by low-noise amplifier 21 B 2 can be output simultaneously. For example, n 77 of 5G-NR and B 42 of 4G-LTE, whose frequency bands are in an inclusion relation, can be simultaneously received (EN-DC).

Furthermore, for the passband of filters 11 C and 11 D included in multiplexer 11 , it is possible to apply any one of wireless LAN (2.4 GHz), wireless LAN (5 GHz) which includes B 46 and B 47 of LTE, low band group (617 MHz to 960 MHz), GPS (registered trademark)-L 1 (1559 MHz to 1606 MHz), GPS-L 5 (1166 MHz to 1229 MHz), middle band group (1427 MHz to 2200 MHz), high band group (2300 MHz to 2690 MHz), and ultrahigh band group (3300 MHz to 4990 MHz).

3. Circuit Configuration of Low-Noise Amplifiers 21 B 1 and 21 B 2 According to the Embodiment

FIG. 3A illustrates an example of a circuit configuration of low-noise amplifiers 21 B 1 and 21 B 2 according to the embodiment.

Each of low-noise amplifiers 21 B 1 and 21 B 2 includes, for example, field-effect transistors (FET) which have a gate terminal, a drain terminal, and a source terminal, and has a configuration in which a plurality of transistors are connected in multiple stages.

Low-noise amplifier 21 B 1 includes source-ground FETs 30 a , 30 b , and 30 c which are connected in cascade. The gate terminal of FET 30 a is connected to an input terminal, the drain terminal of FET 30 a is connected to the gate terminal of FET 30 b , the drain terminal of FET 30 b is connected to the gate terminal of FET 30 c , and the drain terminal of FET 30 c is connected to an output terminal. Low-noise amplifier 21 B 1 includes three transistors connected in multiple stages.

Low-noise amplifier 21 B 2 includes source-ground FETs 30 a and 30 b which are connected in cascade. The gate terminal of FET 30 a is connected to an input terminal, the drain terminal of FET 30 a is connected to the gate terminal of FET 30 b , and the drain terminal of FET 30 b is connected to an output terminal. Low-noise amplifier 21 B 2 includes two transistors connected in multiple stages.

Specifically, the number of stages of transistors included in low-noise amplifier 21 B 1 is different from the number of stages of transistors included in low-noise amplifier 21 B 2 . In this embodiment, the number of stages of transistors included in low-noise amplifier 21 B 1 is larger than the number of stages of transistors included in low-noise amplifier 21 B 2 .

Because the number of stages of transistors of low-noise amplifier 21 B 1 and the number of stages of transistors of low-noise amplifier 21 B 2 are different, the frequency bandwidth in which low-noise amplifiers 21 B 1 and 21 B 2 can amplify by at least a predetermined gain can be adjusted. In particular, because the number of stages of transistors included in low-noise amplifier 21 B 1 is larger than the number of stages of transistors included in low-noise amplifier 21 B 2 , the frequency bandwidth in which low-noise amplifier 21 B 1 can amplify by a predetermined gain can be adjusted more widely than the frequency bandwidth in which low-noise amplifier 21 B 2 can amplify by a predetermined gain.

It should be noted that low-noise amplifiers 21 B 1 and 21 B 2 may be configured using bipolar amplification transistors. Furthermore, low-noise amplifiers 21 B 1 and 21 B 2 may each include a capacitor and an inductor which are connected to a plurality of transistors.

Furthermore, low-noise amplifier 21 B 1 according to this embodiment may be configured using transistors including GaAs or SiGe, for example. According to this, low-noise amplifier 21 B 1 can ensure high gain and low distortion characteristics while ensuring a wide frequency band in which amplification by at least a predetermined gain is possible.

On the other hand, low-noise amplifier 21 B 2 according to this embodiment may be configured using a transistor having a CMOS-SOI (silicon on insulator) structure, for example. According to this, low-noise amplifier 21 B 2 can ensure high gain, low power consumption, low distortion characteristics, and low cost while ensuring a narrow frequency band in which amplification by at least a predetermined gain is possible.

FIG. 3BA is an outline diagram illustrating an example of a circuit configuration of low-noise amplifier 21 B 2 according to Variation embodiment 1 of the embodiment and FIG. 3BB illustrates example gain-frequency characteristics thereof. As illustrated in the figure, low-noise amplifier 21 B 2 according to this variation embodiment includes FETs 30 a and 30 b , switch 31 , and capacitor 32 . Compared to low-noise amplifier 21 B 2 in FIG. 1 according to the embodiment, low-noise amplifier 21 B 2 in FIG. 3BA according to this variation embodiment is different in configuration only in the addition of switch 31 and capacitor 32 , and thus low-noise amplifier 21 B 2 in FIG. 3BA according to this variation embodiment will be described below omitting the descriptions of elements that are the same as in low-noise amplifier 21 B 2 in FIG. 1 according to the embodiment and focusing on the elements that are different.

Switch 31 is an example of a second switch, and the circuit in which switch 31 and capacitor 32 are connected in series is connected between the gate terminal of FET 30 b and a ground. The circuit in which switch 31 and capacitor 32 are connected in series is a variable capacitance circuit in which the capacitance added to low-noise amplifier 21 B 2 is variable according to the connection and disconnection of switch 31 .

As illustrated in the graph on FIG. 3BB , the frequency band in which amplification by at least a predetermined gain is performed shifts to the low frequency side when switch 31 is placed in the off-state, and the frequency band in which amplification by at least a predetermined gain is performed shifts to the high frequency side when switch 31 is placed in the on-state, for example.

According to this, the frequency band in which amplification by at least a predetermined gain is to be performed can be changed according to the communication band to be used.

It should be noted that the frequency band in which low-noise amplifier 21 B 2 amplifies a radio-frequency signal by at least the predetermined gain is variable within the frequency band in which low-noise amplifier 21 B 1 amplifies a radio-frequency signal by at least the predetermined gain.

According to this, the relation in which the frequency band in which low-noise amplifier 21 B 1 can amplify by at least the predetermined gain includes the frequency band in which low-noise amplifier 21 B 2 can amplify by at least the predetermined gain is maintained.

It should be noted that the connection point of the variable capacitance circuit is not limited to the gate terminal of FET 30 b . Furthermore, the variable capacitance circuit may be a circuit in which switch 31 and capacitor 32 are connected in parallel.

Furthermore, the variable capacitance circuit may be added to low-noise amplifier 21 B 1 or 21 A.

FIG. 3C is a circuit configuration diagram of radio-frequency circuit 7 according to Variation embodiment 2 of the embodiment. As illustrated in the figure, radio-frequency circuit 7 according to this variation embodiment includes common terminal 100 (illustration omitted), multiplexer 11 (illustration omitted), filter 12 A (illustration omitted) and 12 B (illustration omitted), switch 13 , low-noise amplifiers 21 A, 21 B 1 , 21 B 3 , 21 B 4 , 21 B 5 , and 21 B 6 , and reception output terminals 110 A, 110 B 1 , 110 B 3 , 110 B 4 , 110 B 5 , and 110 B 6 . Compared to radio-frequency circuit 1 according to the embodiment, radio-frequency circuit 7 according to this variation embodiment is different only in including switch 14 and low-noise amplifiers 21 B 3 to 21 B 6 in place of low-noise amplifier 21 B 2 , and thus radio-frequency circuit 7 according to this variation embodiment will be described below omitting the descriptions of elements that are the same as in radio-frequency circuit 1 according to the embodiment and focusing on the elements that are different.

Switch 14 , which is an example of a third switch, includes common terminal 14 a , selection terminal 14 b , selection terminal 14 c , selection terminal 14 d , and selection terminal 14 e , and switches between the connection between common terminal 14 a and selection terminal 14 b , the connection between common terminal 14 a and selection terminal 14 c , the connection between common terminal 14 a and selection terminal 14 d , and the connection between common terminal 14 a and selection terminal 14 e.

Low-noise amplifier 21 B 3 , which is an example of a first amplifier circuit, includes an input terminal connected to selection terminal 14 b and an output terminal connected to reception output terminal 110 B 3 , amplifies a radio-frequency signal input via common terminal 14 a and selection terminal 14 b and outputs the amplified radio-frequency signal from reception output terminal 110 B 3 to RFIC 3 . The frequency band (corresponding to communication band B 1 ) in which low-noise amplifier 21 B 3 amplifies radio-frequency signals by at least a predetermined gain includes the frequency band (corresponding to communication band B 3 ) in which low-noise amplifier 21 B 3 amplifies radio-frequency signals by at least a predetermined gain.

Low-noise amplifier 21 B 4 , which is an example of a second amplifier circuit, includes an input terminal connected to selection terminal 14 c and an output terminal connected to reception output terminal 110 B 4 , amplifies radio-frequency signals input via common terminal 14 a and selection terminal 14 c and outputs the amplified radio-frequency signal from reception output terminal 110 B 4 to RFIC 3 . The frequency band in which low-noise amplifier 21 B 4 amplifies radio-frequency signals by at least a predetermined gain includes the frequency band (corresponding to communication band B 4 ) in which low-noise amplifier 21 B 4 amplifies radio-frequency signals by at least a predetermined gain.

Low-noise amplifier 21 B 5 includes an input terminal connected to selection terminal 14 d and an output terminal connected to reception output terminal 110 B 5 , amplifies a radio-frequency signal input via common terminal 14 a and selection terminal 14 d and outputs the amplified radio-frequency signal from reception output terminal 110 B 5 to RFIC 3 . The frequency band in which low-noise amplifier 21 B 5 amplifies a radio-frequency signal by at least a predetermined gain includes the frequency band (corresponding to communication band B 5 ) in which low-noise amplifier 21 B 5 amplifies radio-frequency signals by at least a predetermined gain.

Low-noise amplifier 21 B 6 includes an input terminal connected to selection terminal 14 e and an output terminal connected to reception output terminal 110 B 6 , amplifies a radio-frequency signal input via common terminal 14 a and selection terminal 14 e and outputs the amplified radio-frequency signals from reception output terminal 110 B 6 to RFIC 3 . The frequency band in which low-noise amplifier 21 B 6 amplifies a radio-frequency signal by at least a predetermined gain includes the frequency band (corresponding to communication band B 6 ) in which low-noise amplifier 21 B 6 amplifies radio-frequency signals by at least a predetermined gain.

Furthermore, the frequency band in which low-noise amplifier 21 B 3 amplifies radio-frequency signals by at least the predetermined gain, the frequency band in which low-noise amplifier 21 B 4 amplifies a radio-frequency signal by at least the predetermined gain, the frequency band in which low-noise amplifier 21 B 5 amplifies radio-frequency signals by at least the predetermined gain, and the frequency band in which low-noise amplifier 21 B 6 amplifies a radio-frequency signal by at least the predetermined gain do not overlap with one another.

In this variation embodiment, for example, n 79 of 5G-NR may be applied as communication band A, n 77 of 5G-NR may be applied as communication band B 1 , n 78 of 5G-NR may be applied as communication band B 3 , B 42 of 4G-LTE may be applied as communication band B 4 , B 43 of 4G-LTE may be applied as communication band B 5 , and B 48 or B 49 (or a band including B 48 and B 49 ) of 4G-LTE may applied as communication band B 6 .

According to this configuration, since each of the frequency bands in which low-noise amplifiers 21 B 3 to 21 B 6 amplify radio-frequency signals by at least the predetermined gain is included in the frequency band in which low-noise amplifier 21 B 1 amplifies radio-frequency signals by at least the predetermined gain, low-noise amplifiers 21 B 3 to 21 B 6 are more capable of enhancing amplification performance such as maximum gain, power consumption, and signal distortion. Therefore, for example, compared to a case where the single low-noise amplifier 21 B 1 amplifies radio-frequency signals of communication band B 1 corresponding to the frequency band in which low-noise amplifier 21 B 1 is capable of amplifying by at least a predetermined gain and radio-frequency signals of the communication band corresponding to the frequency band in which each of low-noise amplifiers 21 B 3 to 21 B 6 is capable of amplifying by at least the predetermined gain, high amplification performance such as high gain, low power consumption, and low signal distortion can be obtained.

4. Structure of Filters

FIG. 4A is a diagram illustrating an example of a circuit configuration of filter 11 B included in multiplexer 11 according to the embodiment. As illustrated in the figure, filter 11 B includes series-arm resonators s 1 , s 2 , s 3 , and s 4 , parallel-arm resonators p 1 , p 2 , and p 3 , and inductors L 1 and L 2 .

Series-arm resonators s 1 to s 4 are acoustic wave resonators, and are disposed in series on a path connecting common terminal 100 and connection node n 2 . Parallel-arm resonators p 1 to p 3 are acoustic wave resonators, and each is disposed between a ground and a node that is on the path connecting common terminal 100 , series-arm resonators s 1 to s 4 , and connection node n 2 .

Each of serial-arm resonators s 1 to s 4 and parallel-arm resonators p 1 to p 3 have a respective resonant frequency in which an impedance becomes minimized and an anti-resonant frequency in which an impedance becomes maximized, and the passband of filter 11 B is determined by making the anti-resonant frequencies of parallel-arm resonators p 1 to p 3 and the resonant frequencies of serial-arm resonators s 1 to s 4 approximately the same. It should be noted that the number of serial-arm resonators and parallel-arm resonators can vary. Specifically, filter 11 B forms a ladder bandpass filter including a plurality of acoustic wave resonators. It should be noted that filter 11 B is not limited to a ladder bandpass filter, and may be a longitudinally-coupled filter, and the like.

Inductor L 1 is connected between parallel-arm resonator p 1 and a ground, and is a passive element for adjusting an attenuation pole in the attenuation band of filter 11 B. Inductor L 2 is connected between connection node n 2 and a ground, and is a passive element for adjusting an attenuation pole in the attenuation band of filter 11 B or matching impedances of the circuit elements connected to connection node n 2 and filter 11 B. It should be noted that in place of inductors L 1 and L 2 , capacitors may be provided, or both an inductor and a capacitor may be provided.

In other words, the passband of filter 11 B in this example is determined according to parallel-arm resonators p 1 to p 3 and serial-arm resonators s 1 to s 4 only. On the other hand, the attenuation band of filter 11 B in this example is determined according to parallel-arm resonators p 1 to p 3 , serial-arm resonators s 1 to s 4 , as well as inductors L 1 and L 2 .

The above-described structure makes it possible to miniaturize and reduce the cost of multiplexer 11 which includes filter 11 B.

It should be noted that, in filter 11 B in this example, a switch may be connected to at least one of the acoustic wave resonators, inductor L 1 , or inductor L 2 . In this case, for example, the passband of filter 11 B can be changed by switching one of the aforementioned switches in accordance with the switching of the communication band to be used.

Furthermore, in filter 11 B in this example, inductors L 1 and L 2 are not necessary, and filter 11 B may be formed with only acoustic wave resonators.

Furthermore, each of filters 11 A, 11 C, and 11 D may have the structure that filter 11 B in this example has. By providing filters 11 A to 11 D with the above-described structure, multiplexer 11 can be integratedly provided on a single piezoelectric substrate, thereby promoting miniaturization.

FIG. 4B is diagram illustrating an example of a circuit configuration of filter 12 B according to the embodiment. As illustrated in the figure, filter 12 B includes capacitors C 1 , C 2 , C 3 , C 4 , C 5 , C 6 , C 7 , and C 8 , and inductors L 4 , L 5 , L 6 , and L 7 .

Capacitor C 1 , capacitor C 2 , the parallel circuit of inductor L 4 and capacitor C 3 , and the parallel circuit of inductor L 5 and capacitor C 4 are disposed in series on the path connecting connection node n 2 and common terminal 13 a . The series circuit of inductor L 6 and capacitor C 5 , the series circuit of inductor L 7 and capacitor C 6 , capacitor C 7 , and capacitor C 8 are each disposed between a ground and a node on the path connecting connection node n 2 and common terminal 13 a.

Inductor L 4 and capacitor C 3 form an LC parallel resonance circuit. Inductor L 5 and capacitor C 4 form an LC parallel resonance circuit. Inductor L 6 and capacitor C 5 form an LC series resonance circuit. Inductor L 7 and capacitor C 6 form an LC series resonance circuit.

The passband and attenuation band of filter 12 B are determined by adjusting the resonant frequencies of the LC parallel resonance circuits and the resonant frequencies of the LC series resonance circuits. It should be noted that although the number and connection relationship of the inductors and capacitors can vary, it is desirable to include at least one of the LC parallel resonance circuits or the LC series resonance circuits. According to this configuration, the LC series resonant frequencies or the LC parallel resonant frequencies can be used as attenuation poles, and thus a wider attenuation band can be realized.

It should be noted that, in filter 12 B in this example, a switch may be connected to at least one of the inductors and or at least one of the capacitors. In this case, for example, the passband of filter 12 B can be changed by switching one of the aforementioned switches in accordance with the switching of the communication band to be used. Furthermore, the unnecessary waves of the radio-frequency signals to be input to low-noise amplifiers 21 B 1 and 21 B 2 can be suppressed in accordance with the switching of the communication band to be used.

Furthermore, filter 12 A may also have the structure described in this example.

5. Configuration of Radio-Frequency Circuit 6 According to Variation 3

FIG. 5 is an example of a circuit configuration diagram of radio-frequency circuit 6 and antenna element 2 according to Variation embodiment 3 of the embodiment. As illustrated in the figure, radio-frequency circuit 6 according to this variation embodiment includes common terminal 100 , multiplexer 11 , filters 12 A, 12 B 1 , and 12 B 2 , switch 13 , low-noise amplifiers 21 A, 21 B 1 , and 21 B 2 , and reception output terminals 110 A, 110 B 1 , and 110 B 2 .

Compared to radio-frequency circuit 1 according to the embodiment, radio-frequency circuit 6 according to this variation embodiment is different in configuration only in that filters 12 B 1 and 12 B 2 are provided in place of filter 12 B, and thus radio-frequency circuit 6 according to this variation embodiment will be described below omitting elements that are the same as those in radio-frequency circuit 1 according to the embodiment and focusing on the elements that are different.

Low-noise amplifier 21 B 1 , which is an example of a first low-noise amplifier, includes an input terminal (a first input terminal) connected to selection terminal 13 b 1 via filter 12 B 1 , and an output terminal (a first output terminal) connected to reception output terminal 110 B 1 . Low-noise amplifier 21 B 1 is capable of amplifying radio-frequency signals of communication band B 1 , for example.

Low-noise amplifier 21 B 2 , which is an example of a second low-noise amplifier, includes an input terminal (second input terminal) connected to selection terminal 13 b 2 via filter 12 B 2 , and an output terminal (second output terminal) connected to reception output terminal 110 B 2 . Low-noise amplifier 21 B 2 is capable of amplifying radio-frequency signals of communication band B 2 , for example.

Here, the frequency band in which low-noise amplifier 21 B 1 amplifies radio-frequency signals by at least a predetermined gain includes the frequency band in which low-noise amplifier 21 B 2 amplifies radio-frequency signals by at least the predetermined gain. Correspondingly, communication band B 1 includes communication band B 2 .

According to this configuration, the frequency band in which at least the predetermined gain is achieved is narrower for low-noise amplifier 21 B 2 than for low-noise amplifier 21 B 1 , and thus low-noise amplifier 21 B 2 is more capable of enhancing amplification performance such as maximum gain, power consumption, and signal distortion. Therefore, according to radio-frequency circuit 6 according to this variation, it is possible to obtain high amplification performance such as high gain, low power consumption, and low signal distortion compared to, for example, the case where the single low-noise amplifier 21 B 1 amplifies radio-frequency signals of communication band B 1 corresponding to the frequency band in which low-noise amplifier 21 B 1 is capable of amplifying by at least a predetermined gain and radio-frequency signals of communication band B 2 corresponding to the frequency band in which low-noise amplifier 21 B 2 is capable of amplifying by at least a predetermined gain. Furthermore, since filters 12 B 1 and 12 B 2 corresponding to the respective frequency bands in which low-noise amplifiers 21 B 1 and 21 B 2 are capable of amplifying by at least a predetermined gain are disposed upstream of low-noise amplifiers 21 B 1 and 21 B 2 , it becomes possible to suppress the unnecessary waves of the radio-frequency signals to be input to low-noise amplifiers 21 B 1 and 21 B 2 , and the S/N ratio of the radio-frequency signals output from low-noise amplifiers 21 B 1 and 21 B 2 improves.

It should be noted that switch 13 , filters 12 B 1 and 12 B 2 , and low-noise amplifiers 21 B 1 and 21 B 2 may be radio-frequency module 20 obtained by forming switch 13 , filters 12 B 1 and 12 B 2 , and low-noise amplifiers 21 B 1 and 21 B 2 on the same substrate. Furthermore, switch 13 and low-noise amplifiers 21 B 1 and 21 B 2 may be configured using a semiconductor IC formed on a single chip.

6. Advantageous Effects

As described above, according to this embodiment, radio frequency circuit 1 includes: switch 13 that includes common terminal 13 a , selection terminal 13 b 1 and selection terminal 13 b 2 and switches between connecting common terminal 13 a and selection terminal 13 b 1 and connecting common terminal 13 a and selection terminal 13 b 2 ; low-noise amplifier 21 B 1 including an input terminal connected to selection terminal 13 b 1 ; and low-noise amplifier 21 B 2 including an input terminal connected to selection terminal 13 b 2 . Here, the frequency band in which low-noise amplifier 21 B 1 amplifies radio-frequency signals by at least a predetermined gain includes the frequency band in which low-noise amplifier 21 B 2 amplifies radio-frequency signals by at least a predetermined gain.

According to this, the frequency band in which at least the predetermined gain is achieved is narrower for low-noise amplifier 21 B 2 than for low-noise amplifier 21 B 1 , and thus low-noise amplifier 21 B 2 is more capable of achieving a high maximum gain, a low power consumption, and a low signal distortion. Therefore, the radio-frequency signals can be amplified with high amplification performances compared to, for example, the case where the single low-noise amplifier 21 B 1 amplifies both radio-frequency signals of communication band B 1 corresponding to the frequency band in which low-noise amplifier 21 B 1 is capable of amplifying by at least a predetermined gain and radio-frequency signals of communication band B 2 corresponding to the frequency band in which low-noise amplifier 21 B 2 is capable of amplifying by at least a predetermined gain.

Furthermore, according to this embodiment, low-noise amplifier 21 B 1 has, as a possible amplification band, a first frequency band in which low-noise amplifier 21 B 1 is capable of amplifying the radio-frequency signals by at least a gain that is smaller than a maximum gain value of low-noise amplifier 21 B 1 by a predetermined value, low-noise amplifier 21 B 2 has, as a possible amplification band, a second frequency band in which the first low-noise amplifier is capable of amplifying the radio-frequency signals by at least a gain that is smaller than a maximum gain value of the second low-noise amplifier by a predetermined value, and the first frequency band includes the second frequency band.

According to this configuration, a high gain, a low power consumption, and a low signal distortion can be obtained compared to, for example, the case where the single low-noise amplifier 21 B 1 amplifies both the radio-frequency signals of communication band B 1 corresponding to the first frequency band and the radio-frequency signals of communication band B 2 corresponding to the second frequency band.

Furthermore, according to this embodiment, radio frequency circuit 1 may further include filter 12 B that is connected to common terminal 13 a and has a passband that includes the first frequency band.

According to this configuration, unnecessary waves of radio-frequency signals to be input to low-noise amplifiers 21 B 1 and 21 B 2 can be suppressed upstream of low-noise amplifiers 21 B 1 and 21 B 2 , and thus the S/N ratio of the radio-frequency signals output from low-noise amplifiers 21 B 1 and 21 B 2 improves.

Furthermore, according to this embodiment, the passband of filter 12 B may be variable.

According to this configuration, the unnecessary waves of the radio-frequency signals to be input to low-noise amplifiers 21 B 1 and 21 B 2 can be suppressed according to the communication band to be used.

Furthermore, according to this embodiment, the first frequency band may be a frequency band that includes n 77 of NR, and the second frequency band may be a frequency band that includes at least one of n 78 of NR, B 42 of LTE, B 43 of LTE, B 48 of LTE, or B 49 of LTE.

According to this configuration, a 5G-NR radio-frequency signal and a 4G-LTE radio-frequency signal can be amplified with high amplifier performance.

Furthermore, according to this embodiment, low-noise amplifier 21 B 1 and low-noise amplifier 21 B 2 may each include a plurality of transistors connected in multiple stages, and the number of stages of the plurality of transistors included in low-noise amplifier 21 B 1 may be different from the number of stages of the plurality of transistors included in low-noise amplifier 21 B 2 .

According to this configuration, the frequency bandwidths of low-noise amplifiers 21 B 1 and 21 B 2 can be adjusted through the number of stages of the transistors.

Furthermore, according to Variation embodiment 1 of this embodiment, at least one of low-noise amplifier 21 B 1 or low-noise amplifier 21 B 2 may further include a variable-capacitance circuit having a capacitance that is variable, and the variable-capacitance circuit may include capacitor 32 and switch 31 connected to capacitor 32 .

According to this configuration, the frequency band in which amplification by at least a predetermined gain is to be performed can be changed according to the communication band to be used.

Furthermore, according to Variation embodiment 1 of this embodiment, low-noise amplifier 21 B 2 may include the variable-capacitance circuit, and the frequency band in which low-noise amplifier 21 B 2 amplifies the radio-frequency signals by at least a predetermined gain may be variable within the frequency band in which low-noise amplifier 21 B 1 amplifies the radio-frequency signals by at least a predetermined gain, according to switching of switch 31 between an on-state and an off-state.

According to this configuration, the relation in which the frequency band in which low-noise amplifier 21 B 1 can amplify by at least the predetermined gain includes the frequency band in which low-noise amplifier 21 B 2 can amplify by at least the predetermined gain is maintained.

Furthermore, according to this embodiment, switch 13 may switch alternately between connecting common terminal 13 a and selection terminal 13 b 1 and connecting common terminal 13 a and selection terminal 13 b 2 .

According to this configuration, the radio-frequency signal output from one of low-noise amplifiers 21 B 1 and 21 B 2 can be propagated with low loss, without leaking into the other of low-noise amplifiers 21 B 1 and 21 B 2 .

Furthermore, according to this embodiment, in switch 13 , common terminal 13 a may be connected to both selection terminal 13 b 1 and selection terminal 13 b 2 .

According to this configuration, the radio-frequency signal amplified by low-noise amplifier 21 B 1 and the radio-frequency signal amplified by low-noise amplifier 21 B 2 can be output simultaneously.

Furthermore, according to this embodiment, radio frequency circuit 1 includes: switch 13 that includes common terminal 13 a , selection terminal 13 b 1 and selection terminal 13 b 2 and switches between connecting common terminal 13 a and selection terminal 13 b 1 and connecting common terminal 13 a and selection terminal 13 b 2 ; low-noise amplifier 21 B 1 including an input terminal connected to selection terminal 13 b 1 ; and low-noise amplifier 21 B 2 including an input terminal connected to selection terminal 13 b 2 . Low-noise amplifier 21 B 1 and low-noise amplifier 21 B 2 each include a plurality of transistors connected in multiple stages, and the number of stages of the plurality of transistors included in low-noise amplifier 21 B 1 is different from the number of stages of the plurality of transistors included in low-noise amplifier 21 B 2 .

According to this configuration, since the number of stages of the transistors of low-noise amplifiers 21 B 1 and 21 B 2 are different, the frequencies in which low-noise amplifiers 21 B 1 and 21 B 2 amplify by at least a predetermined gain are different. Specifically, maximum gain, power consumption, and signal distortion characteristics are different between low-noise amplifier 21 B 1 and low-noise amplifier 21 B 2 . Therefore, high gain, low power consumption, and low signal distortion can be obtained compared to, for example, the case where the single low-noise amplifier 21 B 1 amplifies both the radio-frequency signal of communication band B 1 corresponding to the frequency band in which low-noise amplifier 21 B 1 is capable of amplifying by at least a predetermined gain and the radio-frequency signal of communication band B 2 corresponding to the frequency band in which low-noise amplifier 21 B 2 is capable of amplifying by at least a predetermined gain.

Furthermore, according to this embodiment, radio-frequency circuit 1 may further include filter 12 B that is connected to common terminal 13 and has a passband that includes (i) a frequency band in which low-noise amplifier 21 B 1 is capable of amplifying a radio-frequency signal by at least a predetermined gain and (ii) a frequency band in which low-noise amplifier 21 B 2 is capable of amplifying a radio-frequency signal by at least a predetermined gain.

According to this configuration, unnecessary waves of radio-frequency signals to be input to low-noise amplifiers 21 B 1 and 21 B 2 can be suppressed upstream of low-noise amplifiers 21 B 1 and 21 B 2 , and thus the S/N ratio of the radio-frequency signals output from low-noise amplifiers 21 B 1 and 21 B 2 improves.

Furthermore, according to this embodiment, radio-frequency circuit 1 may further include: multiplexer 11 disposed upstream of common terminal 13 a of switch 13 . Multiplexer 11 may include at least two filters 11 A and 11 B that have non-overlapping passbands and including input terminals that are in a common connection. Filter 11 B may include an output terminal connected to common terminal 13 a , and have a passband that includes a frequency band in which low-noise amplifier 21 B 1 is capable of amplifying a radio-frequency signal by at least a predetermined gain and a frequency band in which low-noise amplifier 21 B 2 is capable of amplifying a radio-frequency signal by at least a predetermined gain.

According to this, filter 11 B can suppress unnecessary waves of radio-frequency signals to be input to low-noise amplifiers 21 B 1 and 21 B 2 upstream of low-noise amplifiers 21 B 1 and 21 B 2 , and thus the S/N ratio of the radio-frequency signals output from low-noise amplifiers 21 B 1 and 21 B 2 improves. Furthermore, multiplexer 11 makes it possible to multiplex and simultaneously receive radio-frequency signals of two or more communication bands.

Furthermore, according to this embodiment, communication device 5 includes: RFIC 3 that processes a radio-frequency signal received by antenna element 2 ; and radio-frequency circuit 1 that propagates the radio-frequency signal between antenna element 3 and RFIC 3 .

Accordingly, it is possible to provide a communication device capable of amplifying radio-frequency signals with high amplification performance.

Although the radio-frequency circuit and communication device according to the present disclosure have been described above based on an exemplary embodiment and variations thereof, the present disclosure is not limited to the foregoing embodiment to the exemplary embodiment and the variations thereof. The present disclosure also encompasses other embodiments achieved by combining arbitrary elements in the above embodiment and variations thereof, variations resulting from various modifications to the embodiment and variations thereof that may be conceived by those skilled in the art without departing from the essence of the present disclosure, and various devices that include the radio-frequency circuit and the communication device according to the present disclosure.

For example, regardless of how large or small the number of stages of the transistors included in low-noise amplifier 21 B 1 and the number of stages of the transistors included in low-noise amplifier 21 B 2 , low-noise amplifier 21 B 1 may be configured using transistors including GaAs or SiGe for example, and low-noise amplifier 21 B 2 may include transistors having a CMOS-SOI structure. According to this, low-noise amplifier 21 B 1 can ensure high gain and low distortion characteristics, and low cost while ensuring a wide frequency band in which amplification by at least a predetermined gain is possible, and low-noise amplifier 21 B 2 can ensure high gain, low power consumption, low distortion characteristics, and low cost while ensuring a narrow frequency band in which amplification by at least a predetermined gain is possible.

For example, in the radio-frequency circuit and communication device according to the exemplary embodiment and the variations thereof, a matching element such as an inductor and capacitor, as well as a switch circuit may be connected between the respective elements. It should be noted that the inductor may include a wire inductor configured by a wire that connects respective elements.

Moreover, in the forgoing embodiment, communication system means a communication system constructed using radio access technology (RAT) defined by a standards organization, etc. (for example, 3GPP or Institute of Electrical and Electronic Engineers (IEEE)). The communication system can use, for example, a 5G-NR system, a 4G-LTE system, a WLAN system, etc., but is not limited to these.

Furthermore, communication band means a frequency band that is defined in advance by a standards organization, etc., for a communication system. The communication band can use, for example, a 5G-NR frequency band, a 4G-LTE frequency band, etc., but is not limited to these.

The present disclosure, as a radio-frequency circuit and a communication device that can be applied to a multiband system, can be widely used in communication apparatuses such as a mobile phone.