Search

US-20260128751-A1 - RADIO FREQUENCY CIRCUIT

US20260128751A1US 20260128751 A1US20260128751 A1US 20260128751A1US-20260128751-A1

Abstract

A radio frequency circuit includes a first band pass filter having a pass band corresponding to the uplink frequency range of LTE Band 28 , a second band pass filter having a pass band corresponding to the downlink frequency range of LTE Band 28 , a third band pass filter having a pass band including the uplink frequency range of LTE Band 28 B and the downlink frequency range of LTE Band 29 , and a switch group.

Inventors

  • Takeshi Oshima
  • Hirotsugu Mori

Assignees

  • MURATA MANUFACTURING CO., LTD.

Dates

Publication Date
20260507
Application Date
20251103
Priority Date
20241106

Claims (10)

  1. 1 . A radio frequency circuit comprising: a radio frequency signal input terminal; a radio frequency signal output terminal; a radio frequency signal input-output terminal; a power amplifier comprising an input terminal that is electrically connected to the radio frequency signal input terminal; a low noise amplifier comprising an output terminal that is electrically connected to the radio frequency signal output terminal; a first band pass filter that has a pass band corresponding to an uplink frequency range of Long Term Evolution (LTE) Band 28 ; a second band pass filter that has a pass band corresponding to a downlink frequency range of LTE Band 28 ; a third band pass filter that has a pass band comprising an uplink frequency range of LTE Band 28 B and a downlink frequency range of LTE Band 29 ; and a switch group comprising a first terminal that electrically connects an output terminal of the power amplifier to a first end of the first band pass filter, a second terminal that electrically connects a second end of the first band pass filter to the radio frequency signal input-output terminal, a third terminal that electrically connects an input terminal of the low noise amplifier to a first end of the second band pass filter, a fourth terminal that electrically connects a second end of the second band pass filter to the radio frequency signal input-output terminal, a fifth terminal that electrically connects the output terminal of the power amplifier to a first end of the third band pass filter, a sixth terminal that electrically connects a second end of the third band pass filter to the radio frequency signal input-output terminal, and a seventh terminal that electrically connects the input terminal of the low noise amplifier to the first end of the third band pass filter.
  2. 2 . The radio frequency circuit according to claim 1 , further comprising: a fourth band pass filter that has a pass band corresponding to an uplink frequency range of LTE Band 20 , wherein the second band pass filter has a pass band comprising the downlink frequency range of LTE Band 28 and a downlink frequency range of LTE Band 20 ; and wherein the switch group electrically connects the output terminal of the power amplifier to a first end of the fourth band pass filter, electrically connects a second end of the fourth band pass filter to the radio frequency signal input-output terminal, electrically connects the input terminal of the low noise amplifier to the first end of the second band pass filter, and electrically connects the second end of the second band pass filter to the radio frequency signal input-output terminal.
  3. 3 . The radio frequency circuit according to claim 1 , wherein in an operation under Power Class (PC) 2 , the switch group electrically connects the output terminal of the power amplifier to the first end of the first band pass filter, electrically connects the second end of the first band pass filter to the radio frequency signal input-output terminal, electrically connects the input terminal of the low noise amplifier to the first end of the second band pass filter, and electrically connects the second end of the second band pass filter to the radio frequency signal input-output terminal; and wherein in an operation under Power Class (PC) 3 , the switch group electrically connects the output terminal of the power amplifier to the first end of the third band pass filter, electrically connects the second end of the third band pass filter to the radio frequency signal input-output terminal, electrically connects the input terminal of the low noise amplifier to the first end of the second band pass filter, and electrically connects the second end of the second band pass filter to the radio frequency signal input-output terminal.
  4. 4 . The radio frequency circuit according to claim 1 , wherein the switch group comprises a first switch, a second switch, and a third switch; wherein the first switch comprises a first terminal that is electrically connected to the output terminal of the power amplifier, a second terminal that is electrically connected to a second terminal of the second switch, a third terminal that is electrically connected to the first end of the first band pass filter, and a fourth terminal that is electrically connected to the first end of the third band pass filter; wherein the second switch comprises a first terminal that is electrically connected to the input terminal of the low noise amplifier, the second terminal that is electrically connected to the second terminal of the first switch, and a third terminal that is electrically connected to the first end of the second band pass filter; and wherein the third switch comprises a first terminal that is electrically connected to the second end of the first band pass filter, a second terminal that is electrically connected to the second end of the second band pass filter, a third terminal that is electrically connected to the second end of the third band pass filter, and a fourth terminal that is electrically connected to the radio frequency signal input-output terminal.
  5. 5 . The radio frequency circuit according to claim 3 , wherein the switch group comprises a first switch, a second switch, and a third switch; wherein the first switch comprises a first terminal that is electrically connected to the output terminal of the power amplifier, a second terminal that is electrically connected to a second terminal of the second switch, a third terminal that is electrically connected to the first end of the first band pass filter, and a fourth terminal that is electrically connected to the first end of the third band pass filter; wherein the second switch comprises a first terminal that is electrically connected to the input terminal of the low noise amplifier, the second terminal that is electrically connected to the second terminal of the first switch, and a third terminal that is electrically connected to the first end of the second band pass filter; and wherein the third switch comprises a first terminal that is electrically connected to the second end of the first band pass filter, a second terminal that is electrically connected to the second end of the second band pass filter, a third terminal that is electrically connected to the second end of the third band pass filter, and a fourth terminal that is electrically connected to the radio frequency signal input-output terminal.
  6. 6 . The radio frequency circuit according to claim 2 , wherein the switch group comprises a first switch, a second switch, and a third switch; wherein the first switch comprises a first terminal that is electrically connected to the output terminal of the power amplifier, a second terminal that is electrically connected to a second terminal of the second switch, a third terminal that is electrically connected to the first end of the first band pass filter, a fourth terminal that is electrically connected to the first end of the third band pass filter, and a fifth terminal that is electrically connected to the first end of the fourth band pass filter; wherein the second switch comprises a first terminal that is electrically connected to the input terminal of the low noise amplifier, the second terminal that is electrically connected to the second terminal of the first switch, and a third terminal that is electrically connected to the first end of the second band pass filter; and wherein the third switch comprises a first terminal that is electrically connected to the second end of the first band pass filter, a second terminal that is electrically connected to the second end of the second band pass filter, a third terminal that is electrically connected to the second end of the third band pass filter, a fourth terminal that is electrically connected to the radio frequency signal input-output terminal, and a fifth terminal that is electrically connected to the second end of the fourth band pass filter.
  7. 7 . The radio frequency circuit according to claim 4 , wherein when radio frequency signals in LTE Band 28 are transmitted and received by the radio frequency circuit: the first switch electrically connects the first terminal to the third terminal, the second switch electrically connects the first terminal to the third terminal, and the third switch electrically connects the first terminal to the fourth terminal and electrically connects the second terminal to the fourth terminal; wherein when radio frequency signals in LTE Band 28 B are transmitted and received by the radio frequency circuit: the first switch electrically connects the first terminal to the fourth terminal, the second switch electrically connects the first terminal to the third terminal, and the third switch electrically connects the second terminal to the fourth terminal and electrically connects the third terminal to the fourth terminal; and wherein when a radio frequency signal in LTE Band 29 are received by the radio frequency circuit: the first switch electrically connects the second terminal to the fourth terminal, the second switch electrically connects the first terminal to the second terminal, and the third switch electrically connects the third terminal to the fourth terminal.
  8. 8 . The radio frequency circuit according to claim 6 , wherein when radio frequency signals in LTE Band 28 are transmitted and received by the radio frequency circuit: the first switch electrically connects the first terminal to the third terminal, the second switch electrically connects the first terminal to the third terminal, and the third switch electrically connects the first terminal to the fourth terminal and electrically connects the second terminal to the fourth terminal; wherein when radio frequency signals in LTE Band 28 B are transmitted and received by the radio frequency circuit: the first switch electrically connects the first terminal to the fourth terminal, the second switch electrically connects the first terminal to the third terminal, and the third switch electrically connects the second terminal to the fourth terminal and electrically connects the third terminal to the fourth terminal; and wherein when a radio frequency signal in LTE Band 29 are received by the radio frequency circuit: the first switch electrically connects the second terminal to the fourth terminal, the second switch electrically connects the first terminal to the second terminal, and the third switch electrically connects the third terminal to the fourth terminal.
  9. 9 . The radio frequency circuit according to claim 6 , wherein when radio frequency signals in LTE Band 20 are transmitted and received by the radio frequency circuit: the first switch electrically connects the first terminal to the fifth terminal, the second switch electrically connects the first terminal to the third terminal, and the third switch electrically connects the second terminal to the fourth terminal and electrically connects the fourth terminal to the fifth terminal.
  10. 10 . The radio frequency circuit according to claim 4 , wherein in an operation under Power Class (PC) 2 : the first switch electrically connects the first terminal to the third terminal, the second switch electrically connects the first terminal to the third terminal, and the third switch electrically connects the first terminal to the fourth terminal and electrically connects the second terminal to the fourth terminal; and wherein in an operation under Power Class (PC) 3 , the first switch electrically connects the first terminal to the fourth terminal, the second switch electrically connects the first terminal to the third terminal, and the third switch electrically connects the second terminal to the fourth terminal and electrically connects the third terminal to the fourth terminal.

Description

CROSS REFERENCE TO RELATED APPLICATION This application claims priority from Japanese Patent Application No. 2024-194423, filed on November 6, 2024. The content of this application is incorporated herein by reference in its entirety. BACKGROUND OF THE DISCLOSURE 1. Field of the Disclosure The present disclosure relates to a radio frequency circuit. 2. Description of the Related Art U.S. Patent Application Publication No. 2013/0244722 describes a radio frequency circuit that transmits and receives radio frequency signals in multiple bands. BRIEF SUMMARY OF THE DISCLOSURE Long Term Evolution (LTE) Band 28 is divided into Band 28A on the low frequency side and Band 28B on the high frequency side for operational purposes. Band 28 includes a 45 MHz uplink frequency range from 703 MHz (megahertz) to 748 MHz and a 45 MHz downlink frequency range from 758 MHz to 803 MHz. Band 28A includes a 30 MHz uplink frequency range from 703 MHz to 733 MHz and a 30 MHz downlink frequency range from 758 MHz to 788 MHz. Band 28B includes a 30 MHz uplink frequency range from 718 MHz to 748 MHz and a 30 MHz downlink frequency range from 773 MHz to 803 MHz. In the present 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", uplink may be referred to as "UL", and downlink may be referred to as "DL". In recent years, there has been market demand for performing communications using a frequency band with a bandwidth greater than or equal to 40 MHz for each of uplink and downlink in Band 28. However, as described above, each of the uplink frequency range and the downlink frequency range in each of Band 28A and Band 28B has only a 30 MHz bandwidth. For this reason, it is necessary to use Band 28. The frequency range from 470 MHz to 710 MHz is used for digital terrestrial television broadcasting in some countries (for example, Japan). For this reason, a specification called NS_17 is defined by the Third Generation Partnership Project (3GPP) (registered trademark) for the use of Band 28B. In other words, when using Band 28B, it is necessary to suppress signals in the frequency range from 470 MHz to 710 MHz. Also, Band 29 is only for downlink. The frequency range of Band 29 is from 717 MHz to 728 MHz. In other words, Band 29 is included in the uplink frequency range of Band 28. In the present disclosure, Band 29 may be referred to as "B29". For the above reasons, a radio frequency circuit requires many filters and switches to transmit and receive radio frequency signals in Band 28, Band 28B, and Band 29. The present disclosure is made in view of the above problem, and a possible benefit of the present disclosure is to transmit and receive radio frequency signals in Band 28, Band 28B, and Band 29 while preventing an increase in the circuit size. According to an aspect of the present disclosure, a radio frequency circuit includes a radio frequency signal input terminal; a radio frequency signal output terminal; a radio frequency signal input-output terminal; a power amplifier including an input terminal that is electrically connected to the radio frequency signal input terminal; a low noise amplifier including an output terminal that is electrically connected to the radio frequency signal output terminal; a first band pass filter that has a pass band corresponding to the uplink frequency range of Long Term Evolution (LTE) Band 28; a second band pass filter that has a pass band corresponding to the downlink frequency range of LTE Band 28; a third band pass filter that has a pass band including the uplink frequency range of LTE Band 28B and the downlink frequency range of LTE Band 29; and a switch group including a first terminal that electrically connects the output terminal of the power amplifier to a first end of the first band pass filter, a second terminal that electrically connects a second end of the first band pass filter to the radio frequency signal input-output terminal, a third terminal that electrically connects the input terminal of the low noise amplifier to a first end of the second band pass filter, a fourth terminal that electrically connects a second end of the second band pass filter to the radio frequency signal input-output terminal, a fifth terminal that electrically connects the output terminal of the power amplifier to a first end of the third band pass filter, a sixth terminal that electrically connects a second end of the third band pass filter to the radio frequency signal input-output terminal, and a seventh terminal that electrically connects the input terminal of the low noise amplifier to the first end of the third band pass filter. The present disclosure makes it possible to transmit and receive radio frequency signals in Band 28, Band 28B, and Band 29 while preventing an increase in the circuit size. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS FIG. 1 is a diagram illustrating the frequency ranges of Long Term Evolution