# US 10,873,355 B2 · High frequency circuit, front-end circuit, and communication device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,873,355 B2 - Document ID: US10873355B2 - Status: Granted - Kind: B2 - Application number: 16/818,410 - Filed: 2020-03-13 - Published: 2020-07-09 - Granted: 2020-12-22 - Earliest claimed: 2017-09-15 - Assignees: Murata Manufacturing Co., Ltd. - Applicants: Murata Manufacturing Co., Ltd. - Inventors: Daisuke Watanabe - Web page: https://patentgrep.com/patent/US10873355B2 ## CPC - H04B 1/18: Input circuits, e.g. for coupling to an antenna or a transmission line (coupling networks between antennas or lines and receivers independent of the nature of the receiver H03H) - H03F 1/565: {using inductive elements} - H03F 3/19: with semiconductor devices only - H03F 3/195: in integrated circuits - H03F 3/72: Gated amplifiers, i.e. amplifiers which are rendered operative or inoperative by means of a control signal - H04B 1/006: {using switches for selecting the desired band (H04B1/0057 takes precedence)} - H03F 2200/111: the amplifier being a dual or triple band amplifier, e.g. 900 and 1800 MHz, e.g. switched or not switched, simultaneously or not - H03F 2200/222: A circuit being added at the input of an amplifier to adapt the input impedance of the amplifier - H03F 2200/294: the amplifier being a low noise amplifier [LNA] - H03F 2200/451: the amplifier being a radio frequency amplifier - H03F 2203/7209: the gated amplifier being switched from a first band to a second band - H04B: TRANSMISSION - H03F: AMPLIFIERS ## Abstract A high frequency circuit (4) includes a first terminal (40a), a second terminal (51a), a third terminal (51b), a first path, a second path, a first matching element (41) and a first amplifier (50a) both arranged in the first path, a first switch (42) connected between a reference terminal and a part of the first path, the part spanning between the first matching element and the first amplifier, a second matching element (43) and a second amplifier (50b) both arranged in the second path, and a second switch (44) connected between the reference terminal and a part of the second path, the part spanning between the second matching element and the second amplifier. ## Claims ### Claim 1 A high frequency circuit comprising: a first terminal, a second terminal, and a third terminal; a first path connected between the first terminal and the second terminal and transferring a signal in a first frequency band; a second path connected between the first terminal and the third terminal and transferring the signal in a second frequency band that is different from the first frequency band; a first matching element and a first amplifier both arranged in the first path; a first switch connected between a reference terminal and a part of the first path, the part of the first path spanning between the first matching element and the first amplifier; a second matching element and a second amplifier both arranged in the second path; and a second switch connected between the reference terminal and a part of the second path, the part of the second path spanning between the second matching element and the second amplifier, wherein the first switch is turned to an off-state and the second switch is turned to an on-state when the signal is transferred to the first path, and the first switch is turned to an on-state and the second switch is turned to an off-state when the signal is transferred to the second path. ### Claim 2 (depends on 1) The high frequency circuit according to claim 1, further comprising a third switch having at least one common terminal, wherein the at least one common terminal is connected to the first terminal. ### Claim 3 (depends on 2) The high frequency circuit according to claim 2, wherein the at least one common terminal comprises one common terminal, and the at least one common terminal is the first terminal. ### Claim 4 (depends on 3) The high frequency circuit according to claim 3, further comprising a third matching element that is connected between a common junction point between the first matching element and the second matching element and the at least one common terminal. ### Claim 5 (depends on 3) A communication device comprising: a front-end circuit comprising: a demultiplexer; a plurality of filters; and the high frequency circuit according to claim 3; and an RF signal processing circuit. ### Claim 6 (depends on 2) The high frequency circuit according to claim 2, wherein the at least one common terminal comprises a plurality of common terminals, and the plurality of common terminals are electrically connected to each other. ### Claim 7 (depends on 2) The high frequency circuit according claim 2, further comprising: a fourth terminal; a third path connected between the first terminal and the fourth terminal and transferring the signal in a third frequency band that is different from the first frequency band and the second frequency band; a fourth matching element and a third amplifier both arranged in the third path; and a fourth switch connected between the reference terminal and a part of the third path, the part of the third path spanning between the fourth matching element and the third amplifier, wherein, when the signal is transferred to any one of the first path, the second path, and the third path, one of the first switch, the second switch, or the fourth switch arranged between the reference terminal and the any one path through which the signal is transferred, is turned to an off-state and at least one of the first switch, the second switch, or the fourth switch arranged between the reference terminal and a path other than the any one path through which the signal is transferred, is turned to an on-state. ### Claim 8 (depends on 2) A front-end circuit comprising: a demultiplexer; a plurality of filters; and the high frequency circuit according to claim 2. ### Claim 9 (depends on 8) The front-end circuit according to claim 8, wherein each of the plurality of filters is a receive filter configured to filter the signal in one of the first frequency band or the second frequency band. ### Claim 10 (depends on 2) A communication device comprising: a front-end circuit comprising: a demultiplexer; a plurality of filters; and the high frequency circuit according to claim 2; and an RF signal processing circuit. ### Claim 11 (depends on 10) The communication device according to claim 10, wherein each of the plurality of filters is a receive filter configured to filter the signal in one of the first frequency band or the second frequency band. ### Claim 12 (depends on 1) The high frequency circuit according claim 1, further comprising: a fourth terminal; a third path connected between the first terminal and the fourth terminal and transferring the signal in a third frequency band that is different from the first frequency band and the second frequency band; a fourth matching element and a third amplifier both arranged in the third path; and a fourth switch connected between the reference terminal and a part of the third path, the part of the third path spanning between the fourth matching element and the third amplifier, wherein, when the signal is transferred to any one of the first path, the second path, and the third path, one of the first switch, the second switch, or the fourth switch arranged between the reference terminal and the any one path through which the signal is transferred, is turned to an off-state and at least one of the first switch, the second switch, or the fourth switch arranged between the reference terminal and a path other than the any one path through which the signal is transferred, is turned to an on-state. ### Claim 13 (depends on 12) A front-end circuit comprising: a demultiplexer; a plurality of filters; and the high frequency circuit according to claim 12. ### Claim 14 (depends on 13) The front-end circuit according to claim 13, wherein each of the plurality of filters is a receive filter configured to filter the signal in one of the first frequency band, the second frequency band, or the third frequency band. ### Claim 15 (depends on 12) A communication device comprising: a front-end circuit comprising: a demultiplexer; a plurality of filters; and the high frequency circuit according to claim 12; and an RF signal processing circuit. ### Claim 16 (depends on 15) The communication device according to claim 15, wherein each of the plurality of filters is a receive filter configured to filter the signal in one of the first frequency band, the second frequency band, or the third frequency band. ### Claim 17 (depends on 1) A front-end circuit comprising: a demultiplexer; a plurality of filters; and the high frequency circuit according to claim 1. ### Claim 18 (depends on 17) The front-end circuit according to claim 17, wherein each of the plurality of filters is a receive filter configured to filter the signal in one of the first frequency band or the second frequency band. ### Claim 19 (depends on 1) A communication device comprising: a front-end circuit comprising: a demultiplexer; a plurality of filters; and the high frequency circuit according to claim 1; and an RF signal processing circuit. ### Claim 20 (depends on 19) The communication device according to claim 19, wherein each of the plurality of filters is a receive filter configured to filter the signal in one of the first frequency band or the second frequency band.