High-frequency circuits and communication devices

Abstract

The high-frequency circuit (1) comprises: a diplexer (10) composed of a filter (11) and a filter (12), wherein the filter (11) has a passband including a first frequency band group, and the filter (12) has a passband including a second frequency band group; a notch filter (21) connected to the filter (11) and having a frequency band not included in the first communication frequency band as a stopband; a notch filter (31) connected to the filter (12) and having a frequency band not included in the second communication frequency band as a stopband; and switches (14 and 15) connected to the notch filters (21 and 31), wherein no bandpass filter having the first communication frequency band as a passband is connected between the filter (11) and the switches (14 and 15), and no bandpass filter having the second communication frequency band as a passband is connected.

Description

Technical Field

[0001] The present invention relates to a high-frequency circuit and a communication device. Background Art

[0002] In 5GNR (5th Generation New Radio), a communication frequency band for time division duplex (TDD) with a wider bandwidth (hereinafter also referred to as a TDD band) can be used, and research on the efficient use of such a wide-bandwidth TDD band is underway.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application No. 2017-527155 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] However, when transmitting signals of multiple TDD frequency bands with low loss in an existing high-frequency circuit, the high-frequency circuit is composed of an antenna multiplexer that separates or combines the signals of the frequency band group to which the multiple TDD frequency bands belong with the signals of other frequency band groups, and multiple bandpass filters with each TDD frequency band as a passband. Therefore, the circuit structure becomes complicated and large-scale.

[0008] Therefore, the present invention provides a simplified and compact high-frequency circuit and communication device capable of transmitting signals in a plurality of different TDD frequency bands with low loss.

[0009] Solutions for solving problems

[0010] The high-frequency circuit involved in one embodiment of the present invention comprises: a first multiplexer, which is composed of a first filter and a second filter, the first filter having a passband including a first frequency band group, the first frequency band group including a first communication frequency band for time division duplexing (TDD) and a second communication frequency band for TDD, the second filter having a passband including a second frequency band group, the frequency of the second frequency band group not overlapping with the frequency of the first frequency band group; a first band-stop filter, which is connected to the first filter and uses a frequency band not included in the first communication frequency band as a stop band; and a second band-stop filter, which is connected to the first filter and uses a frequency band not included in the second communication frequency band as a stop band. The frequency band of the communication frequency band is a stop band; and a first switching circuit, which is connected between the first band-stop filter and the first transmit input terminal for receiving the first transmit signal from the outside and the first receive output terminal for outputting the first receive signal to the outside, and is connected between the second band-stop filter and the second transmit input terminal for receiving the second transmit signal from the outside and the second receive output terminal for outputting the second receive signal to the outside, wherein, between the first filter and the first switching circuit, there is no band-pass filter with the first communication frequency band as the passband connected, and there is no band-pass filter with the second communication frequency band as the passband connected.

[0011] Effects of the Invention

[0012] According to the present invention, it is possible to provide a simplified and compact high-frequency circuit and a communication device capable of transmitting signals in a plurality of different TDD frequency bands with low loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a circuit configuration diagram of a high-frequency circuit and a communication device according to the first embodiment.

[0014] Figure 2 Graph showing the pass characteristics of the first band-elimination filter according to the first embodiment.

[0015] Figure 3 Graph showing the pass characteristics of the second band rejection filter according to the first embodiment.

[0016] Figure 4 3 is a circuit configuration diagram of a high-frequency circuit and a communication device according to a comparative example.

[0017] Figure 5 This is a circuit configuration diagram of a high-frequency circuit and a communication device according to the second embodiment. DETAILED DESCRIPTION

[0018] The following drawings are used to describe the embodiments of the present invention in detail. The embodiments described below are all general or specific examples. The numerical values, shapes, materials, components, configurations of components, and connection methods shown in the following embodiments are merely examples and are not intended to limit the present invention.

[0019] In addition, the figures are schematic diagrams that have been appropriately emphasized, omitted, or adjusted in ratio to illustrate the present invention, and are not necessarily strictly illustrated, and may differ from actual shapes, positional relationships, and ratios. In the figures, substantially the same structures may be denoted by the same reference numerals and repeated descriptions may be omitted or simplified.

[0020] In the circuit structure of the present disclosure, "connected" includes not only direct connection via connection terminals and / or wiring conductors, but also electrical connection via other circuit elements. Furthermore, "connected between A and B" means connected to both A and B.

[0021] (Implementation 1)

[0022] [1.1 Circuit Structures of High-Frequency Circuit 1 and Communication Device 5]

[0023] Reference Figure 1 The circuit configurations of the high-frequency circuit 1 and the communication device 5 according to this embodiment will be described. Figure 1 It is a circuit configuration diagram of the high-frequency circuit 1 and the communication device 5 according to the first embodiment.

[0024] [1.1.1 Circuit Structure of Communication Device 5]

[0025] First, the circuit structure of the communication device 5 is described. Figure 1 As shown, a communication device 5 according to this embodiment includes high-frequency circuits 1 and 6 , an antenna 2 , an RF signal processing circuit (RFIC) 3 , and a baseband signal processing circuit (BBIC) 4 .

[0026] The high-frequency circuits 1 and 6 transmit high-frequency signals between the antenna 2 and the RFIC 3. The detailed circuit configurations of the high-frequency circuits 1 and 6 will be described later.

[0027] The antenna 2 is connected to the antenna connection terminal 100 of the high-frequency circuit 1 , transmits a high-frequency signal output from the high-frequency circuit 1 , and receives a high-frequency signal from the outside and outputs the high-frequency signal to the high-frequency circuit 1 .

[0028] RFIC 3 is an example of a signal processing circuit that processes high-frequency signals. Specifically, RFIC 3 processes high-frequency receive signals input via the receive paths of high-frequency circuits 1 and 6 through down-conversion and other signal processing, and outputs the resulting receive signals to BBIC 4. RFIC 3 also processes transmit signals input from BBIC 4 through up-conversion and other signal processing, and outputs the resulting high-frequency transmit signals to the transmit paths of high-frequency circuits 1 and 6. RFIC 3 also includes a control unit that controls switches and amplifiers included in high-frequency circuits 1 and 6. Furthermore, some or all of the functions of RFIC 3 as a control unit may be installed external to RFIC 3, for example, on BBIC 4, high-frequency circuit 1, or 6.

[0029] BBIC 4 is a baseband signal processing circuit that performs signal processing using an intermediate frequency band lower in frequency than the high-frequency signals transmitted by high-frequency circuits 1 and 6. Signals processed by BBIC 4 include, for example, image signals for displaying images and / or audio signals for making calls via a speaker.

[0030] In addition, in the communication device 5 according to the present embodiment, the antenna 2 , the high-frequency circuit 6 , and the BBIC 4 are not essential components.

[0031] [1.1.2 Circuit Structure of High-Frequency Circuit 1]

[0032] Next, the circuit structure of the high frequency circuit 1 will be described. Figure 1 As shown, the high-frequency circuit 1 includes a diplexer 10 , notch filters 21 and 31 , switches 13 , 14 and 15 , power amplifiers 25 and 35 , an antenna connection terminal 100 , transmission input terminals 110 and 120 , and reception output terminals 130 and 140 .

[0033] The antenna connection terminal 100 is connected to the antenna 2 .

[0034] Transmit input terminal 110 is an example of a first transmit input terminal and is a terminal for receiving a first transmit signal from outside high-frequency circuit 1. Specifically, transmit input terminal 110 is a terminal for receiving a first transmit signal in a first communication frequency band for TDD from RFIC 3.

[0035] Transmit input terminal 120 is an example of a second transmit input terminal and is a terminal for receiving a second transmit signal from outside high-frequency circuit 1. Specifically, transmit input terminal 110 is a terminal for receiving a second transmit signal in the first communication frequency band for TDD from RFIC 3.

[0036] The reception output terminal 130 is an example of a first reception output terminal and is a terminal for outputting a first reception signal to the outside of the high-frequency circuit 1. Specifically, the reception output terminal 130 is a terminal for supplying a first reception signal in a first communication frequency band to the RFIC 3.

[0037] The reception output terminal 140 is an example of a second reception output terminal and is a terminal for outputting a second reception signal to the outside of the high-frequency circuit 1. Specifically, the reception output terminal 130 is a terminal for supplying a first reception signal in the second communication frequency band to the RFIC 3.

[0038] In addition, the communication frequency band refers to a frequency band pre-defined for a communication system by a standardization organization, such as 3GPP (3rd Generation Partnership Project), IEEE (Institute of Electrical and Electronics Engineers), etc. A communication system refers to a communication system constructed using radio access technology (RAT: Radio Access Technology). Examples of communication systems that can be used include, but are not limited to, 5GNR systems, LTE (Long Term Evolution) systems, and WLAN (Wireless Local Area Network) systems.

[0039] In this embodiment, the frequency band n77 (band: 3300MHz-4200MHz) used for 5GNR is used as the first communication frequency band, and the frequency band n79 (band: 4400MHz-5000MHz) used for 5GNR is used as the second communication frequency band. In addition, the combination of the first communication frequency band and the second communication frequency band is not limited to the combination of frequency bands n77 and n79. For example, frequency band n78 (band: 3300MHz-3800MHz) can be used instead of frequency band n77 as the first communication frequency band. In addition, the first communication frequency band and the second communication frequency band can also be communication frequency bands for different communication systems. For example, a combination of any two frequency bands among the frequency bands used for 5GNR, LTE and WLAN can also be used as the first communication frequency band and the second communication frequency band. In addition, millimeter wave bands above 7 GHz can also be used as the first communication frequency band and / or the second communication frequency band.

[0040] Diplexer 10 is an example of a first multiplexer and includes filters 11 and 12. Filter 11 is an example of a first filter and has a passband that includes a first frequency band group, which includes a first communication frequency band for time division duplexing (TDD) and a second communication frequency band for TDD. Filter 12 is an example of a second filter and has a passband that includes a second frequency band group, the frequencies of which do not overlap with those of the first frequency band group.

[0041] Furthermore, the first multiplexer is not limited to a diplexer, and may be a multiplexer that divides and / or combines three or more frequency band groups.

[0042] One terminal of the filter 11 and one terminal of the filter 12 are connected to the antenna connection terminal 100. The other terminal of the filter 11 is connected to the switch 13. The other terminal of the filter 12 is connected to the switch 63 of the high-frequency circuit 6.

[0043] In this embodiment, the first frequency band group is, for example, an ultra-high frequency band (UHB: 3.3 GHz to 5 GHz), including 5G NR frequency bands n77 and n79. The second frequency band group is, for example, a mid-high frequency band (MHB: 1.5 GHz to 2.8 GHz), including 4G LTE frequency bands B1 (transmit band: 1920 MHz-1980 MHz, receive band: 2110 MHz-2170 MHz), B3 (transmit band: 1710 MHz-1785 MHz, receive band: 1805 MHz-1880 MHz), B7 (transmit band: 2500 MHz-2570 MHz, receive band: 2620 MHz-2690 MHz), and B41 (frequency band: 2496 MHz-2690 MHz).

[0044] Furthermore, filter 11 is, for example, a high-pass LC filter having an ultra-high frequency band as its passband, and filter 12 is, for example, a low-pass LC filter having a mid-high frequency band as its passband. Furthermore, if the first frequency band group is located at a lower frequency side than the second frequency band group, filter 11 may be a low-pass LC filter and filter 12 may be a high-pass LC filter.

[0045] Furthermore, an LC filter is a filter whose passband is formed by an inductor and a capacitor.

[0046] The notch filter 21 is an example of a first band-stop filter, and is connected to the filter 11 via the switch 13. The notch filter 21 has a frequency band that is not included in the first communication frequency band as a stop band. In addition, the notch filter 21 has a frequency band that is lower than the stop band and a frequency band that is higher than the stop band as a pass band.

[0047] Notch filter 21 may be, for example, an elastic wave notch filter composed solely of elastic wave resonators arranged in a series arm path or a parallel arm path, or an LC filter composed solely of an LC resonant circuit arranged in a parallel arm path. Furthermore, the first band-stop filter may not be notch filter 21, but may instead be a high-pass LC filter having an attenuation band lower than the first communication frequency band and a passband within the first communication frequency band. Alternatively, the first band-stop filter may be a low-pass LC filter having an attenuation band higher than the first communication frequency band and a passband within the first communication frequency band.

[0048] The notch filter 31 is an example of a second band-stop filter, and is connected to the filter 11 via the switch 13. The notch filter 31 has a frequency band that is not included in the second communication frequency band as a stop band. In addition, the notch filter 31 has a frequency band that is lower than the stop band and a frequency band that is higher than the stop band as a pass band.

[0049] Notch filter 31 may be, for example, an elastic wave notch filter composed solely of elastic wave resonators arranged in a series arm path or a parallel arm path, or an LC filter composed solely of an LC resonant circuit arranged in a parallel arm path. Furthermore, the second band-stop filter may not be notch filter 31, but may instead be a high-pass LC filter with an attenuation band lower than the second communication frequency band and a passband within the second communication frequency band. Alternatively, it may be a low-pass LC filter with an attenuation band higher than the second communication frequency band and a passband within the second communication frequency band.

[0050] Switch 13 is an example of a second switch circuit, and switches between connection and disconnection between filter 11 and notch filter 21, and also switches between connection and disconnection between filter 11 and notch filter 31. Switch 13 has a common terminal and two select terminals. The common terminal of switch 13 is connected to the other terminal of filter 11, one select terminal of switch 13 is connected to one terminal of notch filter 21, and the other select terminal of switch 13 is connected to one terminal of notch filter 21.

[0051] In this connection structure, the switch 13 can switch, for example, based on a control signal from the RFIC 3, (1) the connection between the filter 11 and the notch filter 21, (2) the connection between the filter 11 and the notch filter 31, and (3) the connection between the filter 11 and the notch filters 21 and 31. The switch 13 is formed of, for example, a multi-connection type switch circuit.

[0052] The power amplifier 25 is an example of a first power amplifier, and is connected between the switch 14 and the transmission input terminal 110. The power amplifier 25 can amplify the first transmission signal received by the transmission input terminal 110 in the first communication frequency band.

[0053] The power amplifier 35 is an example of a second power amplifier, and is connected between the switch 14 and the transmission input terminal 120. The power amplifier 35 can amplify the second transmission signal in the second communication frequency band received by the transmission input terminal 120.

[0054] As the power amplifiers 25 and 35 , for example, a multi-stage amplifier and / or a differential amplifier can be used, but the present invention is not limited thereto.

[0055] The switch 14 is part of the first switch circuit and is connected between the notch filter 21 and the power amplifier 25 , and between the notch filter 31 and the power amplifier 35 .

[0056] In this connection configuration, switch 14 switches between connection and disconnection between notch filter 21 and power amplifier 25, and between connection and disconnection between notch filter 31 and power amplifier 35, based on a control signal from RFIC 3, for example. Switch 14 is comprised of, for example, two SPST (Single Pole Single Throw) switches.

[0057] The switch 15 is part of the first switch circuit, and is connected between the notch filter 21 and the reception output terminal 130 , and is also connected between the notch filter 31 and the reception output terminal 140 .

[0058] In this connection configuration, switch 15 switches between connection and disconnection between notch filter 21 and reception output terminal 130, and switches between connection and disconnection between notch filter 31 and reception output terminal 140, based on a control signal from RFIC 3, for example. Switch 15 is comprised of, for example, two SPST (Single Pole Single Throw) switches.

[0059] In addition, switches 14 and 15, for example, switch the connection between the notch filter 21 and the power amplifier 25 and the connection between the notch filter 21 and the receiving output terminal 130 in an exclusive manner based on the control signal from RFIC 3, and switch the connection between the notch filter 31 and the power amplifier 35 and the connection between the notch filter 31 and the receiving output terminal 140 in an exclusive manner.

[0060] Both the switches 14 and 15 are examples of a first switch circuit, and function as a TDD switch that switches between transmission and reception in the first communication frequency band and switches between transmission and reception in the second communication frequency band.

[0061] In the high-frequency circuit 1 according to this embodiment, no bandpass filter having a passband in the first communication frequency band and no bandpass filter having a passband in the second communication frequency band are connected between the filter 11 and the switches 14 and 15 .

[0062] Furthermore, the high-frequency circuit 1 may include a low-noise amplifier connected between the switch 15 and the reception output terminal 130 and / or a low-noise amplifier connected between the switch 15 and the reception output terminal 140 .

[0063] In addition, it can also be, Figure 1 Some of the circuit elements shown in are not included in the high-frequency circuit 1. For example, the high-frequency circuit 1 only needs to include at least the diplexer 10, notch filters 21 and 31, and switches 14 and 15, and may not include other circuit elements.

[0064] Alternatively, the diplexer 10 , the notch filters 21 and 31 , and the switches 13 to 15 may be arranged on the same substrate or in the same package.

[0065] [1.1.3 Circuit Structure of High-Frequency Circuit 6]

[0066] Next, a circuit configuration example of the high-frequency circuit 6 will be described. Figure 1 As shown, high-frequency circuit 6 includes duplexers 71, 72, and 81, a filter 82, switches 63, 64, 65, and 66, power amplifiers 75 and 85, transmission input terminals 210 and 240, and reception output terminals 220, 230, 250, and 260. High-frequency circuit 6 transmits signals in the communication frequency band belonging to the second frequency band group.

[0067] The duplexer 71 has a passband of, for example, the mid-high frequency band B3 . The duplexer 71 has a common terminal connected to the switch 63 , a transmitting terminal connected to the switch 64 , and a receiving terminal connected to the receiving output terminal 220 .

[0068] The duplexer 72 has a passband of, for example, the mid-high frequency band B1 . The duplexer 72 has a common terminal connected to the switch 63 , a transmitting terminal connected to the switch 64 , and a receiving terminal connected to the receiving output terminal 230 .

[0069] The duplexer 81 has a passband of, for example, the mid-high frequency band B7 . The duplexer 81 has a common terminal connected to the switch 63 , a transmission terminal connected to the switch 65 , and a reception terminal connected to the reception output terminal 250 .

[0070] The filter 82 has a passband of, for example, the mid-high frequency band B41 . One terminal of the filter 82 is connected to the switch 63 , and the other terminal of the filter 82 is connected to the switches 65 and 66 .

[0071] The switch 63 is connected between the filter 12 and the duplexers 71, 72, 81, and the filter 82. The switch 63 switches between connection and disconnection between the filter 12 and the duplexer 71, between connection and disconnection between the filter 12 and the duplexer 72, between connection and disconnection between the filter 12 and the duplexer 81, and between connection and disconnection between the filter 12 and the filter 82.

[0072] The power amplifier 75 is connected between the switch 64 and the transmission input terminal 210. The power amplifier 75 can amplify the transmission signal of the frequency band B3 or the frequency band B1 received by the transmission input terminal 210.

[0073] The power amplifier 85 is connected between the switch 65 and the transmission input terminal 240. The power amplifier 85 can amplify the transmission signal of the frequency band B7 or the frequency band B41 received by the transmission input terminal 240.

[0074] As the power amplifiers 75 and 85 , for example, a multi-stage amplifier and / or a differential amplifier can be used, but the present invention is not limited thereto.

[0075] The switch 64 is connected between the transmission filter of the duplexer 71 and the power amplifier 75 , and is also connected between the transmission filter of the duplexer 72 and the power amplifier 75 .

[0076] In this connection structure, the switch 64 switches between connection and disconnection between the transmission filter of the duplexer 71 and the power amplifier 75 , and switches between connection and disconnection between the transmission filter of the duplexer 72 and the power amplifier 75 , for example, based on a control signal from the RFIC 3 .

[0077] The switch 65 is connected between the transmission filter of the duplexer 81 and the power amplifier 85 , and is also connected between the filter 82 and the power amplifier 85 .

[0078] In this connection configuration, the switch 65 switches between connection and disconnection between the transmission filter of the duplexer 81 and the power amplifier 85 , and switches between connection and disconnection between the filter 82 and the power amplifier 85 , based on a control signal from the RFIC 3 , for example.

[0079] The switch 66 is connected between the filter 82 and the reception output terminal 260 .

[0080] In this connection configuration, the switch 66 switches between connection and disconnection between the filter 82 and the reception output terminal 260 based on a control signal from the RFIC 3 , for example.

[0081] In addition, the high-frequency circuit 6 may also have a low-noise amplifier connected between the receiving filter of the duplexer 71 and the receiving output terminal 220, a low-noise amplifier connected between the receiving filter of the duplexer 72 and the receiving output terminal 230, a low-noise amplifier connected between the receiving filter of the duplexer 81 and the receiving output terminal 250, and / or a low-noise amplifier connected between the switch 66 and the receiving output terminal 260.

[0082] In addition, the high-frequency circuit 6 only needs to be a circuit for transmitting the signal of the second frequency band group, and may not be provided. Figure 1 The circuit elements represented in .

[0083] [1.1.4 Circuit Structure of Notch Filters 21 and 31]

[0084] Next, a circuit configuration example of the notch filters 21 and 31 included in the high-frequency circuit 1 will be described.

[0085] Figure 2 This is a graph showing the passband characteristics of notch filter 21 according to Embodiment 1. As shown in this figure, notch filter 21 uses the transmission bands of band B3 and band B1 in the mid-high frequency range as its stopband and band n77 in the ultra-high frequency range as its passband. The second harmonics of the transmission bands of bands B3 and B1 are included in the band n77. Due to this passband characteristic of notch filter 21, the second harmonics of the transmission bands of bands B3 and B1 flow from the transmission path of high-frequency circuit 6 into the reception path of high-frequency circuit 1, thereby suppressing degradation of reception sensitivity. Furthermore, these second harmonics are superimposed on the transmission signal of high-frequency circuit 1, thereby suppressing degradation of the signal quality of the transmission signal.

[0086] Furthermore, the ultra-high frequency band n79 may be used as the stop band of the notch filter 21. This can reduce the mutual interference between the signals in the band n77 and the signals in the band n79.

[0087] Figure 3This is a graph showing the passband characteristics of the second band-rejection filter according to Embodiment 1. As shown in this figure, notch filter 31 uses a portion of the WLAN 5 GHz band as a stopband and the ultra-high frequency band n79 as a passband. The WLAN 5 GHz band is positioned close to the high-frequency side of band n79. Due to the passband characteristics of notch filter 31, signals in the WLAN 5 GHz band flow into the reception path of high-frequency circuit 1, thereby suppressing degradation in reception sensitivity. Furthermore, signals in the WLAN 5 GHz band are superimposed on the transmission signal of high-frequency circuit 1, thereby suppressing degradation in the signal quality of the transmission signal.

[0088] Furthermore, the ultra-high frequency band n77 may be used as the stop band of the notch filter 31. This can reduce the mutual interference between the signal in the band n77 and the signal in the band n79.

[0089] [1.2 Circuit Configurations of High-Frequency Circuit 501 and Communication Device 505 According to Comparative Example]

[0090] Here, refer to Figure 4 The circuit configurations of a high-frequency circuit 501 and a communication device 505 according to a comparative example will be described. Figure 4 : is a circuit diagram of a high frequency circuit 501 and a communication device 505 according to a comparative example. Figure 4 As shown, a communication device 505 according to the comparative example includes high-frequency circuits 501 and 6 , a diplexer 510 , an antenna 2 , an RFIC 3 , and a BBIC 4 .

[0091] The diplexer 510 includes filters 511 and 512. Filter 511 has a passband that includes a first frequency band group that includes a first communication frequency band for TDD and a second communication frequency band for TDD. Filter 512 has a passband that includes a second frequency band group whose frequencies do not overlap with those of the first frequency band group.

[0092] One terminal of filter 511 and one terminal of filter 512 are connected to antenna connection terminal 100. The other terminal of filter 511 is connected to switch 13 of high-frequency circuit 501. The other terminal of filter 512 is connected to switch 63 of high-frequency circuit 6.

[0093] The communication device 505 according to the comparative example differs from the communication device 5 according to Embodiment 1 in the configuration of the high-frequency circuit 501. The communication device 505 according to the comparative example will be described below, focusing on the differences between the high-frequency circuit 501 and the high-frequency circuit 1.

[0094] High-frequency circuit 501 includes bandpass filters 521 and 531, switches 13, 14, and 15, power amplifiers 25 and 35, transmit input terminals 110 and 120, and receive output terminals 130 and 140. High-frequency circuit 501 according to the comparative example differs from high-frequency circuit 1 according to Embodiment 1 in that it does not include diplexer 510 and includes bandpass filters 521 and 531 in place of notch filters 21 and 31. The following description of high-frequency circuit 501 according to the comparative example will omit the similarities with high-frequency circuit 1 and focus on the differences.

[0095] The bandpass filter 521 is connected to the filter 511 via the switch 13 , and has the first communication frequency band as a passband and both a frequency band lower than the first communication frequency band and a frequency band higher than the first communication frequency band as attenuation bands.

[0096] Bandpass filter 521 is, for example, a ladder-type elastic wave filter composed of elastic wave resonators arranged in series and parallel arm paths, a longitudinally coupled elastic wave filter, or an LC filter composed of inductors and capacitors arranged in series and parallel arm paths.

[0097] The bandpass filter 531 is connected to the filter 511 via the switch 13 , and is a band-stop filter having the second communication frequency band as a passband and both a frequency band lower than the second communication frequency band and a frequency band higher than the second communication frequency band as attenuation bands.

[0098] Bandpass filter 531 is, for example, a ladder-type elastic wave filter composed of elastic wave resonators arranged in series and parallel arm paths, a longitudinally coupled elastic wave filter, or an LC filter composed of inductors and capacitors arranged in series and parallel arm paths.

[0099] [1.3 Effects, etc.]

[0100] As described above, the high-frequency circuit 1 involved in this embodiment comprises: a diplexer 10, which is composed of a filter 11 and a filter 12, the filter 11 having a passband including a first frequency band group, the first frequency band group including a first communication frequency band for TDD and a second communication frequency band for TDD, the filter 12 having a passband including a second frequency band group, the frequency of the second frequency band group not overlapping with the frequency of the first frequency band group; a notch filter 21, which is connected to the filter 11 and uses a frequency band not included in the first communication frequency band as a stop band; a notch filter A device 31 is connected to the filter 12, which uses a frequency band not included in the second communication frequency band as a stop band; and switches 14 and 15, which are connected between the notch filter 21 and the transmitting input terminal 110 and the receiving output terminal 130, and are connected between the notch filter 31 and the transmitting input terminal 120 and the receiving output terminal 140, wherein, between the filter 11 and the switches 14 and 15, there is no bandpass filter with the first communication frequency band as a passband connected, and there is no bandpass filter with the second communication frequency band as a passband connected.

[0101] In the high-frequency circuit 501 and the communication device 505 involved in the comparative example, when transmitting signals of the first communication frequency band and the second communication frequency band for TDD with low loss, a diplexer 510, a bandpass filter 521 having a passband of the first communication frequency band, and a bandpass filter 531 having a passband of the second communication frequency band are configured to separate or combine signals of the first frequency band group to which the multiple TDD frequency bands belong with signals of other frequency band groups. However, the passbands and attenuation characteristics of the filter 511 constituting the diplexer 510, the bandpass filter 521 having a passband of the first wideband communication frequency band, and the bandpass filter 531 having a passband of the second wideband communication frequency band partially overlap, and the circuit structures of the two bandpass filters 521 and 531 become complicated and thus large.

[0102] In contrast, the high-frequency circuit 1 according to this embodiment does not include the bandpass filter 521 with the first communication frequency band as its passband, but instead includes the notch filter 21. Furthermore, the bandpass filter 531 with the second communication frequency band as its passband is not included, but instead includes the notch filter 31. Consequently, the circuit structure of the filter disposed between the filter 11 and the switches 14 and 15 can be simplified. Furthermore, the insertion loss outside the stopband, i.e., in the passband, can be reduced, thereby enabling low-loss transmission of signals in the first communication frequency band and signals in the second communication frequency band. Consequently, a simplified, compact high-frequency circuit 1 capable of low-loss transmission of signals in multiple different TDD frequency bands can be provided.

[0103] Furthermore, for example, in the high-frequency circuit 1 according to the present embodiment, the diplexer 10 , the notch filters 21 and 31 , and the switches 14 and 15 may be arranged on the same substrate or in the same package.

[0104] This allows the high-frequency circuit 1 to be miniaturized, and the diplexer 10 to be arranged close to the circuit that transmits signals of the first frequency band group, thereby allowing signals in the first and second communication bands for TDD to be transmitted with low loss.

[0105] Furthermore, for example, in the high-frequency circuit 1 according to this embodiment, the filter 11 may be one of a low-pass LC filter and a high-pass LC filter, and the filter 12 may be the other of the low-pass LC filter and the high-pass LC filter.

[0106] According to this, the diplexer 10 can be configured with a simplified LC filter, and thus the high-frequency circuit 1 can be further simplified and miniaturized.

[0107] Furthermore, for example, the high-frequency circuit 1 according to this embodiment may further include a switch 13 that switches between connection and disconnection between the filter 11 and the notch filter 21 and between connection and disconnection between the filter 11 and the notch filter 31 .

[0108] Accordingly, the isolation between signal transmission in the first communication frequency band and signal transmission in the second communication frequency band can be improved.

[0109] For example, the high-frequency circuit 1 according to this embodiment may further include a power amplifier 25 connected between the switches 14 and 15 and the transmission input terminal 110 , and a power amplifier 35 connected between the switches 14 and 15 and the transmission input terminal 120 .

[0110] Thus, the transmission paths of the first communication band and the second communication band can be shortened by including the power amplifiers 25 and 35 in the high-frequency circuit 1. This allows transmission signals of the first communication band and the second communication band to be transmitted with low loss.

[0111] In addition, for example, in the high-frequency circuit 1 involved in this embodiment, the first communication frequency band may be the frequency band n77 used for 5GNR, and the second communication frequency band may be the frequency band n79 used for 5GNR.

[0112] Furthermore, the communication device 5 according to the present embodiment includes an RFIC 3 that processes a high-frequency signal and a high-frequency circuit 1 that transmits the high-frequency signal between the RFIC 3 and the antenna 2 .

[0113] Thus, the communication device 5 can achieve the same effects as those of the high-frequency circuit 1 .

[0114] In addition, in this embodiment, although the notch filters 21 and 31 and the switches 13 to 15 are configured as independent components, this is not limited to this. Alternatively, a portion of the notch filters 21 and 31 and some or all of the switches 13 to 15 may be built into one or more semiconductor integrated circuits. A semiconductor integrated circuit is an electronic circuit formed on the surface and inside a semiconductor chip (also called a bare chip), also known as a semiconductor component. A semiconductor integrated circuit is, for example, configured using a CMOS (Complementary Metal Oxide Semiconductor), and more specifically, it can be configured using an SOI (Silicon on Insulator) process. This allows for inexpensive manufacturing of semiconductor integrated circuits. In addition, the semiconductor integrated circuit may be configured using at least one of GaAs, SiGe, and GaN. This allows for high-quality semiconductor integrated circuits.

[0115] In this embodiment, the filters 11 and 12 constitute the diplexer 10 , but the present invention is not limited thereto. For example, the filters 11 and 12 may be separate filter components connected to separate terminals of a switch connected to the antenna connection terminal 100 .

[0116] (Implementation Method 2)

[0117] Next, Embodiment 2 will be described. This embodiment differs from Embodiment 1 primarily in that high-frequency circuit 7 includes two diplexers 90 and 95. High-frequency circuit 7 and communication device 8 according to this embodiment will be described with reference to the accompanying drawings, focusing on the differences from Embodiment 1.

[0118] [2.1 Circuit Structure of High-Frequency Circuit 7 and Communication Device 8]

[0119] Reference Figure 5 The circuit configurations of the high-frequency circuit 7 and the communication device 8 according to this embodiment will be described. Figure 5 It is a circuit configuration diagram of a high-frequency circuit 7 and a communication device 8 according to the second embodiment.

[0120] [2.1.1 Circuit Structure of Communication Device 8]

[0121] First, the circuit structure of the communication device 8 is described. Figure 5 As shown, a communication device 8 according to this embodiment includes high-frequency circuits 7 and 6 , antennas 2A and 2B, an RFIC 3 , and a BBIC 4 .

[0122] The high-frequency circuits 7 and 6 transmit high-frequency signals between the antennas 2A and 2B and the RFIC 3. The detailed circuit structure of the high-frequency circuit 7 will be described later.

[0123] Antenna 2A is an example of a first antenna and is connected to antenna connection terminal 101 of high-frequency circuit 7. It transmits the high-frequency signal output from high-frequency circuit 7 and receives a high-frequency signal from the outside and outputs the high-frequency signal to high-frequency circuit 7. Antenna 2B is an example of a second antenna and is connected to antenna connection terminal 102 of high-frequency circuit 7. It transmits the high-frequency signal output from high-frequency circuit 7 and receives a high-frequency signal from the outside and outputs the high-frequency signal to high-frequency circuit 7.

[0124] In addition, in the communication device 8 according to the present embodiment, the antennas 2A and 2B, the high-frequency circuit 6 , and the BBIC 4 are not essential components.

[0125] [2.1.2 Circuit Structure of High-Frequency Circuit 7]

[0126] Next, the circuit structure of the high frequency circuit 7 will be described. Figure 5 As shown, the high-frequency circuit 7 includes diplexers 90 and 95 , notch filters 21 and 31 , switches 13 , 14 , 15 and 16 , power amplifiers 25 and 35 , antenna connection terminals 101 and 102 , transmission input terminals 110 and 120 , and reception output terminals 130 and 140 .

[0127] The antenna connection terminal 101 is connected to the antenna 2A, and the antenna connection terminal 102 is connected to the antenna 2B.

[0128] Diplexer 90 is an example of a second multiplexer and includes filters 91 and 92. Filter 91 is an example of a third filter and has a passband that includes the first communication band for TDD and the first communication band of the second communication band for TDD. The first communication band and the second communication band are included in the first frequency band group. Filter 92 is an example of a fourth filter and has a passband that includes the second frequency band group, whose frequencies do not overlap with those of the first and second communication bands.

[0129] One terminal of filter 91 and one terminal of filter 92 are connected to antenna connection terminal 101 or 102 via switch 16. The other terminal of filter 91 is connected to notch filter 21. The other terminal of filter 92 is connected to switch 63 of high-frequency circuit 6.

[0130] Diplexer 95 is an example of a third multiplexer and includes filters 96 and 97. Filter 96 is an example of a fifth filter and has a passband that includes the first communication frequency band for TDD and the second communication frequency band of the second communication frequency band for TDD. Filter 97 is an example of a sixth filter and has a passband that includes the second frequency band group, the frequencies of which do not overlap with the frequencies of the first communication frequency band and the second communication frequency band.

[0131] One terminal of filter 96 and one terminal of filter 97 are connected to antenna connection terminal 101 or 102 via switch 16. The other terminal of filter 96 is connected to notch filter 31. The other terminal of filter 97 is connected to switch 63 of high-frequency circuit 6.

[0132] In this embodiment, the first frequency band group is, for example, an ultra-high frequency band (3.3 GHz to 5 GHz), including 5G NR bands n77 and n79. The second frequency band group is, for example, a mid-high frequency band (1.5 GHz to 2.8 GHz), including 4G LTE bands B1, B3, B7, and B41.

[0133] Furthermore, filters 91 and 96 are, for example, high-pass LC filters having an ultra-high frequency band as their passband, and filters 92 and 97 are, for example, low-pass LC filters having a mid-high frequency band as their passband. Furthermore, if the first frequency band group is located at a lower frequency side than the second frequency band group, filters 91 and 96 may be low-pass LC filters, and filters 92 and 97 may be high-pass LC filters.

[0134] The notch filter 21 is an example of a third band-stop filter, connected to the filter 91, and having a frequency band not included in the first communication frequency band as a stop band. The notch filter 21 has a frequency band lower than the stop band and a frequency band higher than the stop band as a pass band.

[0135] Notch filter 21 may be, for example, an elastic wave notch filter composed solely of elastic wave resonators arranged in a series arm path or a parallel arm path, or an LC filter composed solely of an LC resonant circuit arranged in a parallel arm path. Furthermore, the third band-stop filter may not be notch filter 21, but may instead be a high-pass LC filter with an attenuation band lower than the first communication frequency band and a passband within the first communication frequency band. Alternatively, the third band-stop filter may be a low-pass LC filter with an attenuation band higher than the first communication frequency band and a passband within the first communication frequency band.

[0136] The notch filter 31 is an example of a fourth band-stop filter, connected to the filter 96, and having a frequency band not included in the second communication frequency band as a stop band. The notch filter 31 has a frequency band lower than the stop band and a frequency band higher than the stop band as a pass band.

[0137] Notch filter 31 may be, for example, an elastic wave notch filter composed solely of elastic wave resonators arranged in a series arm path or a parallel arm path, or an LC filter composed solely of an LC resonant circuit arranged in a parallel arm path. Furthermore, the fourth band-stop filter may not be notch filter 31, but may instead be a high-pass LC filter with an attenuation band lower than the second communication frequency band and a passband within the second communication frequency band. Alternatively, it may be a low-pass LC filter with an attenuation band higher than the second communication frequency band and a passband within the second communication frequency band.

[0138] The switch 16 is an example of a third switch circuit, and switches between connection and disconnection between one of the antennas 2A and 2B and the diplexer 90 , and switches between connection and disconnection between the other of the antennas 2A and 2B and the diplexer 95 .

[0139] In this connection configuration, the switch 16 can switch between connection and disconnection between one of the antennas 2A and 2B and one of the diplexers 90 and 95 based on a control signal from the RFIC 3 , for example.

[0140] Switch 16 also includes a terminal for outputting an SRS (Sounding Reference Signal). The SRS is a signal used to notify the base station which antenna the mobile terminal should use to output its transmission signal. Thus, communication device 8 can use the SRS to notify the base station of information such as which antennas are used to transmit signals in the first and second communication frequency bands.

[0141] In the high-frequency circuit 7 according to this embodiment, a bandpass filter having a passband in the first communication frequency band is not connected between the filter 91 and the switches 14 and 15. Furthermore, a bandpass filter having a passband in the second communication frequency band is not connected between the filter 96 and the switches 14 and 15.

[0142] In addition, it can also be, Figure 5 Some of the circuit elements shown in are not included in the high-frequency circuit 7. For example, the high-frequency circuit 7 only needs to include at least the diplexers 90 and 95, the notch filters 21 and 31, and the switches 14 to 16, and may not include other circuit elements.

[0143] Alternatively, the diplexers 90 and 95 , the notch filters 21 and 31 , and the switches 14 to 16 may be arranged on the same substrate or in the same package.

[0144] [2.2 Effects, etc.]

[0145] As described above, the high-frequency circuit 7 involved in this embodiment comprises: a diplexer 90, which is composed of a filter 91 and a filter 92, the filter 91 having a passband of the first communication frequency band in the first communication frequency band for TDD and the second communication frequency band for TDD, the filter 92 having a passband including the second frequency band group, the frequency of the second frequency band group not overlapping with the frequencies of the first communication frequency band and the second communication frequency band; a diplexer 95, which is composed of a filter 96 and a filter 97, the filter 96 having a passband including the second communication frequency band, the filter 97 having a passband including the second frequency band group; a notch filter 21, which is connected to the filter 91 and takes the frequency band not included in the first communication frequency band as a stopband; a notch filter 31, which is connected to the filter 96 The invention relates to a device for transmitting a signal to a user of the present invention and a device for transmitting a signal to a user of the present invention. The invention relates to a device for transmitting a signal to a user of the present invention and a device for transmitting a signal to a user of the present invention. The invention relates to a device for transmitting a signal to a user of the present invention and a device for transmitting a signal to a user of the present invention. The invention relates to a device for transmitting a signal to a user of the present invention and a device for transmitting a signal to a user of the present invention.

[0146] According to the above structure, a bandpass filter having the first communication frequency band as a passband is not configured but a notch filter 21 is configured instead, and a bandpass filter having the second communication frequency band as a passband is not configured but a notch filter 31 is configured instead. Therefore, the circuit structure of the filter configured between the filter 91 and the switches 14 and 15 can be simplified, and the circuit structure of the filter configured between the filter 96 and the switches 14 and 15 can be simplified. In addition, the insertion loss outside the stop band, i.e., the pass band, can be reduced, so that the signal of the first communication frequency band and the signal of the second communication frequency band can be transmitted with low loss. Thus, a simplified and small high-frequency circuit 7 capable of transmitting signals of multiple different TDD frequency bands with low loss can be provided.

[0147] Furthermore, for example, in the high-frequency circuit 7 according to the present embodiment, the diplexers 90 and 95 , the notch filters 21 and 31 , and the switches 14 to 16 may be arranged on the same substrate or in the same package.

[0148] This allows the high-frequency circuit 7 to be miniaturized, and the diplexers 90 and 95 to be arranged close to the circuit that transmits signals of the first frequency band group, thereby allowing signals in the first and second communication bands for TDD to be transmitted with low loss.

[0149] In addition, for example, in the high-frequency circuit 7 involved in this embodiment, filters 91 and 96 are respectively one of the low-pass LC filter and the high-pass LC filter, and filters 92 and 97 are respectively the other of the low-pass LC filter and the high-pass LC filter.

[0150] Thus, the diplexers 90 and 95 can be configured with simplified LC filters, and thus the high-frequency circuit 7 can be further simplified and miniaturized.

[0151] (Other embodiments)

[0152] While the high-frequency circuit and communication device according to the present invention have been described above based on Embodiments 1 and 2, the high-frequency circuit and communication device according to the present invention are not limited to the above-described embodiments. Other embodiments achieved by combining arbitrary components of the above-described embodiments, modifications of the above-described embodiments that occur to those skilled in the art without departing from the spirit of the present invention, and various devices incorporating the above-described high-frequency circuit and communication device are also encompassed by the present invention.

[0153] For example, in the circuit configurations of the high-frequency circuits and communication devices according to the above-described embodiments, other circuit elements and wirings may be inserted between paths connecting the circuit elements shown in the drawings and the signal paths.

[0154] Industrial applicability

[0155] The present invention can be widely used in communication devices such as mobile phones as a high-frequency circuit arranged in a front end portion.

[0156] Description of Reference Numerals

[0157] 1, 6, 7, 501: High-frequency circuit; 2, 2A, 2B: Antenna; 3: RF signal processing circuit (RFIC); 4: Baseband signal processing circuit (BBIC); 5, 8, 505: Communication device; 10, 90, 95, 510: Diplexer; 11, 12, 82, 91, 92, 96, 97, 511, 512: Filter; 13, 14, 15, 16, 63, 64 4, 65, 66: switches; 21, 31: notch filters; 25, 35, 75, 85: power amplifiers; 71, 72, 81: duplexers; 100, 101, 102: antenna connection terminals; 110, 120, 210, 240: transmit input terminals; 130, 140, 220, 230, 250, 260: receive output terminals; 521, 531: bandpass filters.

Claims

1. A high-frequency circuit comprising: a second multiplexer comprising a third filter and a fourth filter, wherein the third filter has a passband including a first communication frequency band for time division duplexing (TDD) and a second communication frequency band for TDD, and the fourth filter has a passband including a second frequency band group, wherein the frequency of the second frequency band group does not overlap with the frequencies of the first communication frequency band and the second communication frequency band; a third multiplexer composed of a fifth filter and a sixth filter, the fifth filter having a passband including the second communication frequency band, and the sixth filter having a passband including the second frequency band group; a third band-stop filter, connected to the third filter, and having a frequency band not included in the first communication frequency band as a stop band; a fourth band-stop filter, connected to the fifth filter, and having a frequency band not included in the second communication frequency band as a stop band; a first switch circuit connected between the third band-stop filter and a first transmit input terminal for receiving a first transmit signal from the outside and a first receive output terminal for outputting the first receive signal to the outside, and connected between the fourth band-stop filter and a second transmit input terminal for receiving a second transmit signal from the outside and a second receive output terminal for outputting the second receive signal to the outside; as well as a third switching circuit, the third switching circuit switching between connection and disconnection between one of the first antenna and the second antenna and the second multiplexer, and switching between connection and disconnection between the other of the first antenna and the second antenna and the third multiplexer, Wherein, no bandpass filter with the first communication frequency band as a passband is connected between the third filter and the first switch circuit. A bandpass filter having the second communication frequency band as a passband is not connected between the fifth filter and the first switch circuit.

2. The high-frequency circuit according to claim 1, wherein The second multiplexer, the third multiplexer, the third band-stop filter, the fourth band-stop filter, the first switch circuit, and the third switch circuit are configured on a same substrate or in a same package.

3. The high-frequency circuit according to claim 1 or 2, wherein: The third filter and the fifth filter are respectively one of a low-pass LC filter and a high-pass LC filter. The fourth filter and the sixth filter are respectively the other of a low-pass LC filter and a high-pass LC filter.

4. The high-frequency circuit according to claim 1 or 2, wherein: Also features: a first power amplifier connected between the first switch circuit and the first transmit input terminal; and The second power amplifier is connected between the first switch circuit and the second transmission input terminal.

5. The high-frequency circuit according to claim 1 or 2, wherein: The first communication frequency band is the frequency band n77 used for 5GNR, the fifth generation new radio. The second communication frequency band is band n79 for 5GNR.

6. A communication device comprising: a signal processing circuit that processes high-frequency signals; and The high-frequency circuit according to any one of claims 1 to 5, wherein the high-frequency signal is transmitted between the signal processing circuit and an antenna.

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