# US 8,542,077 B2 · High-frequency circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,542,077 B2 - Document ID: US8542077B2 - Status: Granted - Kind: B2 - Application number: 13/009,221 - Filed: 2011-01-19 - Published: 2011-12-08 - Granted: 2013-09-24 - Earliest claimed: 2010-06-04 - Assignees: Kabushiki Kaisha Toshiba - Applicants: Kazutoshi Masuda - Inventors: Kazutoshi Masuda - Web page: https://patentgrep.com/patent/US8542077B2 ## CPC - H03F 1/56: Modifications of input or output impedances, not otherwise provided for - H03F 3/193: with field-effect devices (H03F3/195 takes precedence) - H03F 3/211: {using a combination of several amplifiers (H03F3/60 takes precedence)} - H03F 3/245: {with semiconductor devices only} - H10W 44/20: at high-frequency [HF] or radio frequency [RF] - H03F 2200/165: A filter circuit coupled to the input of an amplifier - H03F 2200/171: A filter circuit coupled to the output of an amplifier - H03F 2200/222: A circuit being added at the input of an amplifier to adapt the input impedance of the amplifier - H03F 2200/387: A circuit being added at the output of an amplifier to adapt the output impedance of the amplifier - H03F 2200/451: the amplifier being a radio frequency amplifier - H10W 44/234: {Arrangements for impedance matching} - H10W 44/251: {for monolithic microwave integrated circuits [MMIC]} - H03F: AMPLIFIERS - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract A high-frequency circuit according to one embodiment of the present invention includes a plurality of transistors, a plurality of input matching circuits, a plurality of output matching circuits, a plurality of resistors, and low-frequency oscillation suppressing circuits. The transistors are arranged on a substrate in parallel. The input matching circuits and output matching circuits are arranged on insulating substrates and connected to the transistors. The oscillation suppressing circuits are a circuit configured by a filter circuit having a desired transmission band and a resistor, and are connected to gate terminals of transistors located on both sides of the transistors, respectively. Each of resistors is formed to include a position closest to the transistor between the input matching circuits and between the output matching circuits. Furthermore, each of resistors has a length at which the oscillation suppressing circuit can suppress oscillation at the lowest frequency in the transmission band. ## Claims ### Claim 1 A high-frequency circuit comprising: a plurality of transistors formed arranged and formed on a semiconductor substrate in parallel to each other; a plurality of input matching circuits arranged on a first insulating substrate and connected to gate terminals of the plurality of transistors; a plurality of output matching circuits arranged on a second insulating substrate and connected to drain terminals of the plurality of transistors; a plurality of resistors formed between the plurality of input matching circuits and between the plurality of output matching circuits; and low-frequency oscillation suppressing circuits, each configured by a filter circuit having a desired transmission band and a resistor and each having one end connected to the respective gate terminal of the transistor located on a respective end of the plurality of transistors and having its other end grounded, wherein each of the resistors is formed to include a position closest to the transistors between the input matching circuits and between the output matching circuits, and each of the resistors has a length at which the low-frequency oscillation suppressing circuit can suppress oscillation at the lowest frequency in the transmission band. ### Claim 2 (depends on 1) The high-frequency circuit according to claim 1, wherein the resistor is an isolation resistor to attenuate a high-frequency signal transmitted on a closed loop including the two adjacent transistors and the two input matching circuits and the two output matching circuits connected to the transistors. ### Claim 3 (depends on 1) The high-frequency circuit according to claim 1, wherein the resistor is formed to have a length to fill in a portion between the input matching circuits and a portion between the output matching circuits. ### Claim 4 (depends on 1) The high-frequency circuit according to claim 1, wherein the resistor consists of a tantalum nitride or nichrome. ### Claim 5 (depends on 1) The high-frequency circuit according to claim 1, wherein the filter circuit of the low-frequency oscillation suppressing circuit is configured by a conductor and a capacitor connected to the gate terminal of the transistor, and a transmission band of the filter circuit is determined by an inductance of the conductor and a capacitance of the capacitor. ### Claim 6 (depends on 1) The high-frequency circuit according to claim 1, further comprising: a branching filter arranged on the first insulating substrate and connected to the plurality of input matching circuits; and a combining filter arranged on the second insulating substrate and connected to the plurality of output matching circuits. ### Claim 7 (depends on 1) The high-frequency circuit according to claim 1, wherein the resistor has a length different from the length of the input matching circuit and the output matching circuit. ### Claim 8 (depends on 7) The high-frequency circuit according to claim 7, wherein the resistor is shorter than the input matching circuit or the output matching circuit. ### Claim 9 (depends on 8) The high-frequency circuit according to claim 8, wherein the resistor is longer than a half the input matching circuit or the output matching circuit. ### Claim 10 (depends on 7) The high-frequency circuit according to claim 7, wherein the resistor is longer than the length of the input matching circuit or the output matching circuit.