High-frequency circuits
The high-frequency circuit design with a power amplifier, low-noise amplifier, and band-pass filters addresses the challenge of large circuit size and sensitivity loss by enabling efficient signal transmission and reception in multiple bands with reduced components and improved performance.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- MURATA MFG CO LTD
- Filing Date
- 2024-11-06
- Publication Date
- 2026-05-19
AI Technical Summary
Existing high-frequency circuits require a large number of filters and switches to transmit and receive signals in LTE Bands 28, 28B, and 29, which results in a large circuit size and potential decreases in receiving sensitivity.
A high-frequency circuit design incorporating a power amplifier, low-noise amplifier, and a group of switches with specific band-pass filters for each band, allowing for efficient signal transmission and reception in Bands 28, 28B, and 29 with a reduced circuit size and improved sensitivity.
The circuit achieves efficient transmission and reception of high-frequency signals in multiple bands while minimizing circuit size and maintaining sensitivity, particularly reducing signal leakage and sensitivity loss.
Smart Images
Figure 2026081969000001_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to a high-frequency circuit.
Background Art
[0002] Patent Document 1 below describes a high-frequency circuit that transmits and receives high-frequency signals in a plurality of bands.
Prior Art Document
Patent Document
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] Conventionally, Band 28 of LTE (Long Term Evolution) has been operated separately into a low-frequency side Band 28A and a high-frequency side Band 28B.
[0005] The frequency of Band 28 has an upload width of 45 MHz from 703 MHz (megahertz) to 748 MHz and a download width of 45 MHz from 758 MHz to 803 MHz.
[0006] The frequency of Band 28A has an upload width of 30 MHz from 703 MHz to 733 MHz and a download width of 30 MHz from 758 MHz to 788 MHz.
[0007] The frequency of Band 28B has an upload width of 30 MHz from 718 MHz to 748 MHz and a download width of 30 MHz from 773 MHz to 803 MHz.
[0008] Hereafter, in this disclosure, Band 28 may be referred to as "B28" or "B28F". Band 28A may be referred to as "B28A". Band 28B may be referred to as "B28B". Upload may be referred to as "UL". Download may be referred to as "DL".
[0009] In recent years, there has been a market demand for communication using frequencies of 40MHz or more for both upload and download in the Band 28 frequency band. However, as mentioned above, Band 28A and Band 28B each only have a bandwidth of 30MHz for upload and download. Therefore, it has become necessary to use Band 28.
[0010] Furthermore, frequencies from 470MHz to 710MHz are used for terrestrial digital television broadcasting in some countries (for example, Japan). Therefore, when using Band 28B, a specification called NS_17 has been defined by 3GPP (Third Generation Partnership Project). In other words, when using Band 28B, it is necessary to suppress signals with frequencies from 470MHz to 710MHz.
[0011] Furthermore, Band 29 is a download-only band. The frequency range for Band 29 is from 717MHz to 728MHz. In other words, the frequency range for Band 29 is included within the upload frequency range for Band 28.
[0012] Hereafter, in this disclosure, Band 29 may be referred to as "B29".
[0013] Based on the above, when transmitting and receiving high-frequency signals in bands 28, 28B, and 29, the high-frequency circuit requires a large number of filters and switches.
[0014] This disclosure has been made in view of the above, and aims to transmit and receive high-frequency signals in bands 28, 28B, and 29 while suppressing the circuit size. [Means for solving the problem]
[0015] One aspect of the present disclosure is a high-frequency circuit comprising a high-frequency signal input terminal, a high-frequency signal output terminal, and a high-frequency signal input / output terminal, wherein the input terminal is electrically connected to the high-frequency signal input terminal and includes a power amplifier, and the output terminal is electrically connected to the high-frequency signal output terminal and includes a low-noise amplifier and LTE (Long Term The system includes a group of switches comprising: a first band-pass filter having a passband for LTE Band 28 upload; a second band-pass filter having a passband for LTE Band 28 download; a third band-pass filter having a passband for LTE Band 28B upload and LTE Band 29 download; a first terminal electrically connecting the output terminal of the power amplifier to one end of the first band-pass filter; a second terminal electrically connecting the other end of the first band-pass filter to the high-frequency signal input / output terminal; a third terminal electrically connecting the input terminal of the low-noise amplifier to one end of the second band-pass filter; a fourth terminal electrically connecting the other end of the second band-pass filter to the high-frequency signal input / output terminal; a fifth terminal electrically connecting the output terminal of the power amplifier to one end of the third band-pass filter; a sixth terminal electrically connecting the other end of the third band-pass filter to the high-frequency signal input / output terminal; and a seventh terminal electrically connecting the input terminal of the low-noise amplifier to one end of the third band-pass filter. [Effects of the Invention]
[0016] According to this disclosure, it is possible to transmit and receive high-frequency signals in bands 28, 28B, and 29 while suppressing the circuit size. [Brief explanation of the drawing]
[0017] [Figure 1] Figure 1 is a diagram illustrating the frequencies of LTE (Long Term Evolution) bands 28 and 29. [Figure 2]FIG. 2 is a diagram showing the configuration of the high-frequency circuit according to the first embodiment. [Figure 3] FIG. 3 is an operational explanatory diagram of the high-frequency circuit according to the first embodiment when transmitting and receiving a high-frequency signal in band 28. [Figure 4] FIG. 4 is an operational explanatory diagram of the high-frequency circuit according to the first embodiment when transmitting and receiving a high-frequency signal in band 28B. [Figure 5] FIG. 5 is an operational explanatory diagram of the high-frequency circuit according to the first embodiment when receiving a high-frequency signal in band 29. [Figure 6] FIG. 6 is a diagram for explaining the frequencies of LTE bands 28 and 28B. [Figure 7] FIG. 7 is a diagram showing the configuration of the high-frequency circuit of the comparative example. [Figure 8] FIG. 8 is an explanatory diagram of the high-frequency circuit according to the first embodiment when transmitting and receiving a high-frequency signal in band 28. [Figure 9] FIG. 9 is a diagram showing the configuration of the high-frequency circuit according to the second embodiment. [Figure 10] FIG. 10 is an operational explanatory diagram of the high-frequency circuit according to the second embodiment when transmitting and receiving a high-frequency signal in band 20.
Embodiments for Carrying Out the Invention
[0018] Hereinafter, embodiments of the present disclosure will be described in detail based on the drawings. Note that the present invention is not limited by this embodiment. Each embodiment is an example, and it is needless to say that partial substitution or combination of the configurations shown in different embodiments is possible. In the following embodiments after the second embodiment, descriptions of matters common to the first embodiment will be omitted, and only different points will be described. In particular, the same operational effects due to the same configuration will not be sequentially mentioned for each embodiment.
[0019] <First Embodiment> (Explanation of Frequencies of Bands 28 and 29) Figure 1 is a diagram illustrating the frequencies of LTE (Long Term Evolution) bands 28 and 29.
[0020] Band 28 has a 45MHz bandwidth for uploads, ranging from 703MHz to 748MHz, and a 45MHz bandwidth for downloads, ranging from 758MHz to 803MHz.
[0021] Band 28A has a 30MHz bandwidth for uploads from 703MHz to 733MHz and a 30MHz bandwidth for downloads from 758MHz to 788MHz.
[0022] Band 28B has a 30MHz bandwidth for uploads from 718MHz to 748MHz and a 30MHz bandwidth for downloads from 773MHz to 803MHz.
[0023] Furthermore, frequencies from 470MHz to 710MHz are used for terrestrial digital television broadcasting in some countries (for example, Japan).
[0024] Therefore, when using Band 28B, a specification called NS_17 has been defined by 3GPP (Third Generation Partnership Project). In other words, when using Band 28B, it is necessary to suppress signals with frequencies from 470MHz to 710MHz.
[0025] Furthermore, Band 29 is a download-only band. The frequency range for Band 29 is from 717MHz to 728MHz. In other words, the frequency range for Band 29 is included within the upload frequency range for Band 28.
[0026] In Japan, Band 28B's upload frequency range from 718MHz to 728MHz and download frequency range from 773MHz to 783MHz is allocated to Company A. Additionally, Band 28B's upload frequency range from 728MHz to 738MHz and download frequency range from 783MHz to 793MHz is allocated to Company B. Furthermore, Band 28B's upload frequency range from 738MHz to 748MHz and download frequency range from 793MHz to 803MHz is allocated to Company C.
[0027] (composition) Figure 2 shows the configuration of the high-frequency circuit of the first embodiment.
[0028] The high-frequency circuit 1 is exemplified as a high-frequency module in which components (e.g., surface mount devices (SMDs)) are mounted on a substrate (e.g., a printed wiring board (PWB)), but the disclosure is not limited thereto. The high-frequency module is exemplified as being mounted on communication devices such as smartphones and tablets, but the disclosure is not limited thereto.
[0029] The high-frequency circuit 1 amplifies and bandpasses the high-frequency signal RF1 input to terminal 1a, and outputs the high-frequency signal RF2 from terminal 1c.
[0030] While it is exemplified that an antenna ANT is electrically connected to terminal 1c, the disclosure is not limited thereto.
[0031] Furthermore, the high-frequency circuit 1 passes the high-frequency signal RF3 input to terminal 1c through a bandwidth and amplifies it, outputting the high-frequency signal RF4 from terminal 1b.
[0032] Terminal 1a corresponds to an example of a "high-frequency signal input terminal" in this disclosure. Terminal 1b corresponds to an example of a "high-frequency signal output terminal" in this disclosure. Terminal 1c corresponds to an example of a "high-frequency signal input / output terminal" in this disclosure. High-frequency signal RF1 and high-frequency signal RF2 correspond to an example of a "high-frequency transmission signal" in this disclosure. High-frequency signal RF3 and high-frequency signal RF4 correspond to an example of a "high-frequency reception signal" in this disclosure.
[0033] The high-frequency circuit 1 includes a power amplifier 11, a first switch 12, a low-noise amplifier 13, a second switch 14, a filter group 15, and a third switch 16.
[0034] The first switch 12 has terminals 12a to 12d.
[0035] The first switch 12 electrically connects terminals 12a and 12c, terminals 12a and 12d, or terminals 12b and 12d.
[0036] The second switch 14 has terminals 14a to 14c.
[0037] The second switch 14 electrically connects terminals 14a and 14b, or terminals 14a and 14c.
[0038] The third switch 16 has terminals 16a to 16d.
[0039] The third switch 16 electrically connects terminals 16a and 16d, terminals 16b and 16d, or terminals 16c and 16d.
[0040] The first switch 12, the second switch 14, and the third switch 16 correspond to an example of a “switch group” in this disclosure. Terminal 12c corresponds to an example of a “first terminal of a switch group” in this disclosure. Terminal 16a corresponds to an example of a “second terminal of a switch group” in this disclosure. Terminal 14c corresponds to an example of a “third terminal of a switch group” in this disclosure. Terminal 16b corresponds to an example of a “fourth terminal of a switch group” in this disclosure. Terminal 12d corresponds to an example of a “fifth terminal of a switch group” in this disclosure. Terminal 16c corresponds to an example of a “sixth terminal of a switch group” in this disclosure. Terminal 12b corresponds to an example of a “seventh terminal of a switch group” in this disclosure.
[0041] Terminal 12a of the first switch 12 corresponds to an example of the "first terminal of the first switch" in this disclosure. Terminal 12b of the first switch 12 corresponds to an example of the "second terminal of the first switch" in this disclosure. Terminal 12c of the first switch 12 corresponds to an example of the "third terminal of the first switch" in this disclosure. Terminal 12d of the first switch 12 corresponds to an example of the "fourth terminal of the first switch" in this disclosure.
[0042] Terminal 14a of the second switch 14 corresponds to an example of the "first terminal of the second switch" in this disclosure. Terminal 14b of the second switch 14 corresponds to an example of the "second terminal of the second switch" in this disclosure. Terminal 14c of the second switch 14 corresponds to an example of the "third terminal of the second switch" in this disclosure.
[0043] Terminal 16a of the third switch 16 corresponds to an example of the "first terminal of the third switch" in this disclosure. Terminal 16b of the third switch 16 corresponds to an example of the "second terminal of the third switch" in this disclosure. Terminal 16c of the third switch 16 corresponds to an example of the "third terminal of the third switch" in this disclosure. Terminal 16d of the third switch 16 corresponds to an example of the "fourth terminal of the third switch" in this disclosure.
[0044] The filter group 15 includes the first band-pass filter 21 to the third band-pass filter 23.
[0045] The first bandpass filter 21 has a passband from 703 MHz to 748 MHz, which is the upload frequency of band 28.
[0046] The second band-pass filter 22 has a passband from 758 MHz to 803 MHz, which is the download frequency for band 28.
[0047] The third band-pass filter 23 has a passband from 718 MHz to 748 MHz, which is the upload frequency for band 28B, and from 717 MHz to 728 MHz, which is the download frequency for band 29. In other words, the third band-pass filter 23 has a combined passband from 717 MHz to 748 MHz.
[0048] The input terminal of the power amplifier 11 is electrically connected to terminal 1a. The output terminal of the power amplifier 11 is electrically connected to terminal 12a of the first switch 12.
[0049] The output terminal of the low-noise amplifier 13 is electrically connected to terminal 1b. The input terminal of the low-noise amplifier 13 is electrically connected to terminal 14a of the second switch 14.
[0050] Terminal 12b of the first switch 12 is electrically connected to terminal 14b of the second switch 14.
[0051] Terminal 12c of the first switch 12 is electrically connected to one end of the first bandpass filter 21.
[0052] Terminal 12d of the first switch 12 is electrically connected to one end of the third bandpass filter 23.
[0053] Terminal 14c of the second switch 14 is electrically connected to one end of the second bandpass filter 22.
[0054] The other end of the first bandpass filter 21 is electrically connected to terminal 16a of the third switch 16.
[0055] The other end of the second bandpass filter 22 is electrically connected to terminal 16b of the third switch 16.
[0056] The other end of the third bandpass filter 23 is electrically connected to terminal 16c of the third switch 16.
[0057] Terminal 16d of the third switch 16 is electrically connected to terminal 1c.
[0058] (Operation when transmitting and receiving high-frequency signals on Band 28) Figure 3 is an explanatory diagram illustrating the operation of the high-frequency circuit of the first embodiment when transmitting and receiving high-frequency signals in band 28.
[0059] When transmitting and receiving high-frequency signals in band 28, the first switch 12 electrically connects terminals 12a and 12c. The second switch 14 electrically connects terminals 14a and 14c. The third switch 16 electrically connects terminals 16a and 16d, and also electrically connects terminals 16b and 16d.
[0060] Arrow 101 in Figure 3 indicates the path through which the transmitted signal (high-frequency signal RF1) of band 28 flows. Arrow 102 indicates the path through which the received signal (high-frequency signal RF3) of band 28 flows.
[0061] As indicated by arrow 101, the path through which the high-frequency signal RF1 flows is terminal 1a → power amplifier 11 → terminal 12a of the first switch 12 → terminal 12c of the first switch 12 → first bandpass filter 21 → terminal 16a of the third switch 16 → terminal 16d of the third switch 16 → terminal 1c.
[0062] Furthermore, as indicated by arrow 102, the path through which the high-frequency signal RF3 flows is as follows: terminal 1c → terminal 16d of the third switch 16 → terminal 16b of the third switch 16 → second bandpass filter 22 → terminal 14c of the second switch 14 → terminal 14a of the second switch 14 → low-noise amplifier 13 → terminal 1b.
[0063] Thus, the high-frequency circuit 1 is capable of transmitting and receiving high-frequency signals in band 28.
[0064] (Operation when transmitting and receiving high-frequency signals in Band 28B) Figure 4 is an explanatory diagram illustrating the operation of the high-frequency circuit of the first embodiment when transmitting and receiving high-frequency signals in band 28B.
[0065] When transmitting and receiving high-frequency signals in band 28B, the first switch 12 electrically connects terminals 12a and 12d. The second switch 14 electrically connects terminals 14a and 14c. The third switch 16 electrically connects terminals 16b and 16d, and also electrically connects terminals 16c and 16d.
[0066] Arrow 111 in Figure 4 indicates the path of the transmitted signal (high-frequency signal RF1) in band 28B. Arrow 112 indicates the path of the received signal (high-frequency signal RF3) in band 28B.
[0067] As indicated by arrow 111, the path through which the high-frequency signal RF1 flows is terminal 1a → power amplifier 11 → terminal 12a of the first switch 12 → terminal 12d of the first switch 12 → third bandpass filter 23 → terminal 16c of the third switch 16 → terminal 16d of the third switch 16 → terminal 1c.
[0068] Furthermore, as indicated by arrow 112, the path through which the high-frequency signal RF3 flows is terminal 1c → terminal 16d of the third switch 16 → terminal 16b of the third switch 16 → second bandpass filter 22 → terminal 14c of the second switch 14 → terminal 14a of the second switch 14 → low-noise amplifier 13 → terminal 1b.
[0069] Thus, the high-frequency circuit 1 is capable of transmitting and receiving high-frequency signals in band 28B.
[0070] (Operation when receiving high-frequency signals in Band 29) Figure 5 is an explanatory diagram of the operation of the high-frequency circuit of the first embodiment when receiving a high-frequency signal in band 29.
[0071] When receiving a high-frequency signal in band 29, the first switch 12 electrically connects terminals 12b and 12d. The second switch 14 electrically connects terminals 14a and 14b. The third switch 16 electrically connects terminals 16c and 16d.
[0072] Arrow 121 in Figure 5 indicates the path through which the received signal (high-frequency signal RF3) in band 29 flows.
[0073] As indicated by arrow 121, the path through which the high-frequency signal RF3 flows is terminal 1c → terminal 16d of the third switch 16 → terminal 16c of the third switch 16 → third bandpass filter 23 → terminal 12d of the first switch 12 → terminal 12b of the first switch 12 → terminal 14b of the second switch 14 → terminal 14a of the second switch 14 → low-noise amplifier 13 → terminal 1b.
[0074] Thus, the high-frequency circuit 1 is capable of receiving high-frequency signals in band 29.
[0075] (effect) (1) The high-frequency circuit 1 is capable of transmitting and receiving high-frequency signals in bands 28, 28B, and 29 with a small circuit size (in the first embodiment, 3 switches and 3 filters).
[0076] (2) Furthermore, the high-frequency circuit 1 can suppress a decrease in receiving sensitivity when transmitting and receiving high-frequency signals in band 28.
[0077] Figure 6 is a diagram illustrating the frequencies of LTE bands 28 and 28B.
[0078] Region 301 in Figure 6 shows the frequency and signal strength of the high-frequency signal for upload in band 28B. Region 302 shows the frequency and signal strength of the low-frequency unwanted components of the high-frequency signal for upload in band 28B. Region 303 shows the frequency and signal strength of the high-frequency unwanted components of the high-frequency signal for upload in band 28B.
[0079] The highest upload frequency for Band 28B is 748MHz. The lowest download frequency for Band 28B is 773MHz. In other words, as indicated by arrow 311, there is a 25MHz difference between the upload and download frequencies for Band 28B.
[0080] Therefore, the signal strength of the unwanted component shown in region 303 is small at frequencies above 773 MHz. In other words, the decrease in receiver sensitivity for downloads in Band 28B due to uploads in Band 28B is small.
[0081] On the other hand, the highest upload frequency for Band 28 is 748 MHz, the same as the highest frequency for Band 28B. The lowest download frequency for Band 28 is 758 MHz. In other words, as indicated by arrow 312, the difference between Band 28 uploads and Band 28 downloads is only 10 MHz.
[0082] Therefore, the signal strength of the unwanted component shown in region 303 (common to bands 28B and 28) is high at 758MHz. In other words, the decrease in receiver sensitivity for band 28 downloads due to uploads on band 28 is significant.
[0083] Therefore, the high-frequency circuit 1 suppresses the decrease in receiving sensitivity when transmitting and receiving high-frequency signals in band 28. This point will be explained using a comparative example.
[0084] Figure 7 shows the configuration of a comparative high-frequency circuit.
[0085] The comparative high-frequency circuit 401, compared to the high-frequency circuit 1 of the first embodiment, includes a first switch 411 and a filter 412 instead of the first switch 12 and filter group 15.
[0086] Compared to filter group 15, filter 412 includes a third filter 421 instead of a third band-pass filter 23.
[0087] The third filter 421 has a passband from 718 MHz to 748 MHz, which is the upload frequency for band 28B.
[0088] Therefore, in the comparative high-frequency circuit 401, the first band-pass filter 21 passes the high-frequency signal of the band 29 download, instead of the third filter 421.
[0089] When the first switch 411 transmits or receives high-frequency signals in band 28, it electrically connects terminals 411a and 411c.
[0090] When the first switch 411 transmits or receives high-frequency signals in band 28B, it electrically connects terminals 411a and 411d.
[0091] When the first switch 411 receives a high-frequency signal in band 29, it electrically connects terminals 411c and 411b.
[0092] Figure 7 shows the case where the high-frequency circuit 401 transmits and receives high-frequency signals in band 28.
[0093] Arrow 431 in Figure 7 indicates the path through which the transmitted signal (high-frequency signal RF1) of band 28 leaks to terminal 1b.
[0094] As indicated by arrow 431, when transmitting and receiving high-frequency signals in band 28, the transmission signal (high-frequency signal RF1) for band 28 output from the power amplifier 11 leaks through the path: power amplifier 11 → terminal 411a of the first switch 411 → terminal 411c of the first switch 411 → terminal 411b of the first switch 411 → terminal 14b of the second switch 14 → terminal 14a of the second switch 14 → low-noise amplifier 13 → terminal 1b, resulting in a decrease in receiving sensitivity.
[0095] Within the path of arrow 431, isolation is provided in section A between terminals 411c and 411b of the first switch 411, and in section B between terminals 14b and 14a of the second switch 14. If the attenuation of the high-frequency signal per section is, for example, 20 dB (decibels), then the high-frequency signal is attenuated by 40 dB over the entire path of arrow 431.
[0096] Figure 8 is an explanatory diagram of the high-frequency circuit of the first embodiment when transmitting and receiving a high-frequency signal in band 28.
[0097] Figure 8 shows the case where the high-frequency circuit 1 transmits and receives high-frequency signals in band 28.
[0098] Arrow 131 in Figure 8 indicates the path through which the transmitted signal (high-frequency signal RF1) of band 28 leaks to terminal 1b.
[0099] As indicated by arrow 131, when transmitting and receiving high-frequency signals in band 28, the transmission signal (high-frequency signal RF1) for band 28 output from the power amplifier 11 leaks through the path of power amplifier 11 → terminal 12a of the first switch 12 → terminal 12d of the first switch 12 → terminal 12b of the first switch 12 → terminal 14b of the second switch 14 → terminal 14a of the second switch 14 → low-noise amplifier 13 → terminal 1b, resulting in a decrease in receiving sensitivity.
[0100] Of the path indicated by arrow 131, isolation is provided in section C between terminals 12a and 12d of the first switch 12, section D between terminals 12d and 12b of the first switch 12, and section E between terminals 14b and 14a of the second switch 14.
[0101] If the attenuation of the high-frequency signal per section is, for example, 20 dB, then the high-frequency signal will be attenuated by as much as 60 dB along the entire path of arrow 131.
[0102] Therefore, compared to the high-frequency circuit 401, the high-frequency circuit 1 can suppress the decrease in receiving sensitivity when transmitting and receiving high-frequency signals in band 28.
[0103] <Second Embodiment> (composition) Figure 9 shows the configuration of the high-frequency circuit in the second embodiment.
[0104] The high-frequency circuit 1A of the second embodiment is capable of further transmitting and receiving high-frequency signals in band 20 compared to the high-frequency circuit 1 of the first embodiment.
[0105] Compared to high-frequency circuit 1, high-frequency circuit 1A includes a first switch 12A, filter group 15A, and third switch 16A, instead of the first switch 12, filter group 15, and third switch 16.
[0106] Compared to filter group 15, filter group 15A includes a second band-pass filter 22A instead of the second band-pass filter 22. Furthermore, compared to filter group 15, filter group 15A further includes a fourth band-pass filter 24A.
[0107] The second band-pass filter 22A has passbands from 758 MHz to 803 MHz, which is the download frequency for band 28, and from 791 MHz to 821 MHz, which is the download frequency for band 20. In other words, the second band-pass filter 22A has a combined passband from 758 MHz to 821 MHz.
[0108] The fourth band-pass filter 24A has a passband from 832 MHz to 862 MHz, which is the upload frequency of band 20.
[0109] The first switch 12A has an additional terminal 12e compared to the first switch 12.
[0110] Terminal 12e of the first switch 12A corresponds to an example of the "fifth terminal of the first switch" in this disclosure.
[0111] Terminal 12e of the first switch 12A is electrically connected to one end of the fourth bandpass filter 24A.
[0112] The first switch 12A electrically connects terminals 12a and 12c, terminals 12a and 12d, terminals 12b and 12d, or terminals 12a and 12e.
[0113] The third switch 16A has an additional terminal 16e compared to the third switch 16.
[0114] Terminal 16e of the third switch 16A corresponds to an example of the "fifth terminal of the third switch" in this disclosure.
[0115] Terminal 16e of the third switch 16A is electrically connected to the other end of the fourth bandpass filter 24A.
[0116] The third switch 16A electrically connects terminals 16a and 16d, terminals 16b and 16d, terminals 16c and 16d, or terminals 16e and 16d.
[0117] (Operation when transmitting and receiving high-frequency signals in bands 28, 28B, and 29) The operation of high-frequency circuit 1A when transmitting and receiving high-frequency signals in bands 28, 28B, and 29 is the same as that of high-frequency circuit 1, so the illustration and explanation are omitted.
[0118] (Operation when transmitting and receiving high-frequency signals in Band 20) Figure 10 is an explanatory diagram illustrating the operation of the high-frequency circuit of the second embodiment when transmitting and receiving high-frequency signals in band 20.
[0119] When transmitting and receiving high-frequency signals in band 20, the first switch 12A electrically connects terminals 12a and 12e. The second switch 14 electrically connects terminals 14a and 14c. The third switch 16A electrically connects terminals 16b and 16d, and also electrically connects terminals 16e and 16d.
[0120] Arrow 141 in Figure 10 indicates the path through which the transmitted signal (high-frequency signal RF1) of band 20 flows. Arrow 142 indicates the path through which the received signal (high-frequency signal RF3) of band 20 flows.
[0121] As indicated by arrow 141, the path through which the high-frequency signal RF1 flows is terminal 1a → power amplifier 11 → terminal 12a of the first switch 12A → terminal 12e of the first switch 12A → fourth bandpass filter 24A → terminal 16e of the third switch 16A → terminal 16d of the third switch 16A → terminal 1c.
[0122] Furthermore, as indicated by arrow 142, the path through which the high-frequency signal RF3 flows is as follows: terminal 1c → terminal 16d of the third switch 16A → terminal 16b of the third switch 16A → second bandpass filter 22A → terminal 14c of the second switch 14 → terminal 14a of the second switch 14 → low-noise amplifier 13 → terminal 1b.
[0123] Thus, the high-frequency circuit 1A is capable of transmitting and receiving high-frequency signals in band 20.
[0124] (effect) The high-frequency circuit 1A is capable of transmitting and receiving high-frequency signals in bands 28, 28B, 29, and 20 with a small circuit size (in the second embodiment, 3 switches and 4 filters).
[0125] <Third Embodiment> (composition) The configuration of the high-frequency circuit in the third embodiment is the same as that of the high-frequency circuit 1 in the first embodiment (see Figure 1), so its illustration and description are omitted.
[0126] (operation) The high-frequency circuit 1 of the third embodiment is capable of operating PC (Power Class) 2 and PC3.
[0127] PC2 has a maximum antenna power of 26 dBm. PC3 has a maximum antenna power of 23 dBm.
[0128] (Operation in the case of PC2) When PC2 is operating, the first switch 12 electrically connects terminals 12a and 12c. The second switch 14 electrically connects terminals 14a and 14c. The third switch 16 electrically connects terminals 16a and 16d, and terminals 16b and 16d.
[0129] As a result, the path through which the high-frequency signal RF1 flows is the same as that of arrow 101 in Figure 3. Similarly, the path through which the high-frequency signal RF3 flows is the same as that of arrow 102 in Figure 3.
[0130] (Operation on PC3) In the operation of PC3, the first switch 12 electrically connects terminals 12a and 12d. The second switch 14 electrically connects terminals 14a and 14c. The third switch 16 electrically connects terminals 16b and 16d, and terminals 16c and 16d.
[0131] As a result, the path through which the high-frequency signal RF1 flows is the same as that of arrow 111 in Figure 4. Also, the path through which the high-frequency signal RF3 flows is the same as that of arrow 112 in Figure 4.
[0132] (effect) When PC2 is operating, the path through which the high-frequency signal RF1 leaks to terminal 1b is the same as arrow 131 in Figure 8.
[0133] Of the path indicated by arrow 131, isolation is provided in section C between terminals 12a and 12d of the first switch 12, section D between terminals 12d and 12b of the first switch 12, and section E between terminals 14b and 14a of the second switch 14.
[0134] If the attenuation of the high-frequency signal per section is, for example, 20 dB, then the high-frequency signal will be attenuated by as much as 60 dB along the entire path of arrow 131.
[0135] Therefore, the high-frequency circuit 1 can suppress the decrease in receiving sensitivity when PC2 is operating.
[0136] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. The present invention may be modified or improved without departing from its spirit, and equivalents thereof are also included. [Explanation of symbols]
[0137] 1. 1A High-Frequency Circuit 11 Power Amplifier 12, 12A 1st switch 13 Low-noise amplifier 14. Second switch 15, 15A filter group 16, 16A 3rd switch 21. First Bandpass Filter 22, 22A Second Bandpass Filter 23. Third Bandpass Filter 24A Fourth Bandpass Filter
Claims
1. A high-frequency circuit comprising a high-frequency signal input terminal, a high-frequency signal output terminal, and high-frequency signal input / output terminals, A power amplifier, in which the input terminal is electrically connected to the high-frequency signal input terminal, A low-noise amplifier whose output terminal is electrically connected to the high-frequency signal output terminal, A first band-pass filter having a passband for LTE (Long Term Evolution) Band 28 upload, A second band-pass filter having a passband for LTE Band 28 downloads, A third band-pass filter having passbands for LTE band 28B upload and LTE band 29 download, A switch group comprising: a first terminal for electrically connecting the output terminal of the power amplifier to one end of the first bandpass filter; a second terminal for electrically connecting the other end of the first bandpass filter to the high-frequency signal input / output terminal; a third terminal for electrically connecting the input terminal of the low-noise amplifier to one end of the second bandpass filter; a fourth terminal for electrically connecting the other end of the second bandpass filter to the high-frequency signal input / output terminal; a fifth terminal for electrically connecting the output terminal of the power amplifier to one end of the third bandpass filter; a sixth terminal for electrically connecting the other end of the third bandpass filter to the high-frequency signal input / output terminal; and a seventh terminal for electrically connecting the input terminal of the low-noise amplifier to one end of the third bandpass filter. including, High-frequency circuits.
2. A high-frequency circuit according to claim 1, A fourth band-pass filter with a passband for LTE Band 20 upload. It further includes, The second band-pass filter has passbands for LTE band 28 download and LTE band 20 download. The aforementioned group of switches, The output terminal of the power amplifier is electrically connected to one end of the fourth bandpass filter, the other end of the fourth bandpass filter is electrically connected to the high-frequency signal input / output terminal, the input terminal of the low-noise amplifier is electrically connected to one end of the second bandpass filter, and the other end of the second bandpass filter is electrically connected to the high-frequency signal input / output terminal. High-frequency circuits.
3. A high-frequency circuit according to claim 1, When operating on a PC (Power Class 2), The aforementioned group of switches, The output terminal of the power amplifier is electrically connected to one end of the first bandpass filter, the other end of the first bandpass filter is electrically connected to the high-frequency signal input / output terminal, the input terminal of the low-noise amplifier is electrically connected to one end of the second bandpass filter, and the other end of the second bandpass filter is electrically connected to the high-frequency signal input / output terminal. When operating on a PC (Power Class 3), The aforementioned group of switches, The output terminal of the power amplifier is electrically connected to one end of the third bandpass filter, the other end of the third bandpass filter is electrically connected to the high-frequency signal input / output terminal, the input terminal of the low-noise amplifier is electrically connected to one end of the second bandpass filter, and the other end of the second bandpass filter is electrically connected to the high-frequency signal input / output terminal. High-frequency circuits.
4. A high-frequency circuit according to claim 1 or 3, The aforementioned group of switches, First switch, second switch, and third switch Includes, The first switch is, The first terminal is electrically connected to the output terminal of the power amplifier, the second terminal is electrically connected to the second terminal of the second switch, the third terminal is electrically connected to one end of the first bandpass filter, and the fourth terminal is electrically connected to one end of the third bandpass filter. The second switch is, The first terminal is electrically connected to the input terminal of the low-noise amplifier, the second terminal is electrically connected to the second terminal of the first switch, and the third terminal is electrically connected to one end of the second band-pass filter. The third switch is, The first terminal is electrically connected to the other end of the first bandpass filter, the second terminal is electrically connected to the other end of the second bandpass filter, the third terminal is electrically connected to the other end of the third bandpass filter, and the fourth terminal is electrically connected to the high-frequency signal input / output terminal. High-frequency circuits.
5. A high-frequency circuit according to claim 2, The aforementioned group of switches, First switch, second switch, and third switch Includes, The first switch is, The first terminal is electrically connected to the output terminal of the power amplifier, the second terminal is electrically connected to the second terminal of the second switch, the third terminal is electrically connected to one end of the first band-pass filter, the fourth terminal is electrically connected to one end of the third band-pass filter, and the fifth terminal is electrically connected to one end of the fourth band-pass filter. The second switch is, The first terminal is electrically connected to the input terminal of the low-noise amplifier, the second terminal is electrically connected to the second terminal of the first switch, and the third terminal is electrically connected to one end of the second band-pass filter. The third switch is, The first terminal is electrically connected to the other end of the first bandpass filter, the second terminal is electrically connected to the other end of the second bandpass filter, the third terminal is electrically connected to the other end of the third bandpass filter, the fourth terminal is electrically connected to the high-frequency signal input / output terminal, and the fifth terminal is electrically connected to the other end of the fourth bandpass filter. High-frequency circuits.
6. A high-frequency circuit according to claim 4 or 5, When transmitting and receiving high-frequency signals in LTE band 28, The first switch electrically connects the first terminal and the third terminal, The second switch electrically connects the first terminal and the third terminal, The third switch electrically connects the first terminal and the fourth terminal, and electrically connects the second terminal and the fourth terminal. When transmitting and receiving high-frequency signals on LTE band 28B, The first switch electrically connects the first terminal and the fourth terminal, The second switch electrically connects the first terminal and the third terminal, The third switch electrically connects the second terminal and the fourth terminal, and electrically connects the third terminal and the fourth terminal, When receiving high-frequency signals in LTE band 29, The first switch electrically connects the second terminal and the fourth terminal, The second switch electrically connects the first terminal and the second terminal, The third switch electrically connects the third terminal and the fourth terminal. High-frequency circuits.
7. A high-frequency circuit according to claim 5, When transmitting and receiving high-frequency signals in LTE band 20, The first switch electrically connects the first terminal and the fifth terminal, The second switch electrically connects the first terminal and the third terminal, The third switch electrically connects the second terminal and the fourth terminal, and electrically connects the fourth terminal and the fifth terminal. High-frequency circuits.
8. A high-frequency circuit according to any one of claims 4 to 7, When operating on a PC (Power Class 2), The first switch electrically connects the first terminal and the third terminal, The second switch electrically connects the first terminal and the third terminal, The third switch electrically connects the first terminal and the fourth terminal, and electrically connects the second terminal and the fourth terminal. When operating on a PC (Power Class 3), The first switch electrically connects the first terminal and the fourth terminal, The second switch electrically connects the first terminal and the third terminal, The third switch electrically connects the second terminal and the fourth terminal, and electrically connects the third terminal and the fourth terminal. High-frequency circuits.