# US 12,015,380 B2 · Radio frequency power amplifier > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,015,380 B2 - Document ID: US12015380B2 - Status: Granted - Kind: B2 - Application number: 17/289,897 - Filed: 2019-10-31 - Published: 2022-01-06 - Granted: 2024-06-18 - Earliest claimed: 2018-10-31 - Assignees: Leonardo UK Ltd - Applicants: Leonardo UK Ltd - Inventors: Daniel Shepphard; Stephen Cripps; Jeffrey Powell; Roberto Quaglia - Web page: https://patentgrep.com/patent/US12015380B2 ## CPC - H03F 1/0288: {using a main and one or several auxiliary peaking amplifiers whereby the load is connected to the main amplifier using an impedance inverter, e.g. Doherty amplifiers} - H03F 1/0266: {by using a signal derived from the input signal} - 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 3/604: {using FET's} - H03F 2200/192: A hybrid coupler being used at the input of an amplifier circuit - H03F 2200/198: A hybrid coupler being used as coupling circuit between stages of an amplifier circuit - H03F 2200/204: A hybrid coupler being used at the output of an amplifier circuit - H03F 2200/321: Use of a microprocessor in an amplifier circuit or its control circuit - H03F 2200/336: A I/Q, i.e. phase quadrature, modulator or demodulator being used in an amplifying circuit - 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 - H03F: AMPLIFIERS ## Abstract A balanced amplifier system having input and output quadrature couplers or equivalents thereof and two amplifiers there between. An RF signal is presented to a first input of an input quadrature coupler such that an amplified RF signal is output at a first output of the output quadrature coupler. A RF control signal is presented to a second input of the quadrature coupler such that an amplified control signal is outputted at the other output of the output quadrature coupler. The system is configured to reflect the amplified signal back into the second port of the output quadrature coupler in order to vary an impedance seen by the amplifiers of the balanced amplifier. ## Claims ### Claim 1 A radio frequency power amplifier system for amplifying an RF signal, the system comprising: a balanced amplifier having an input quadrature coupler, an output quadrature coupler, and two amplifiers there-between; the output quadrature coupler having a first output at which the amplified RF signal will be output; means to modify and/or modulate an impedance at outputs of the two amplifiers, said means including: a radio frequency control signal source connected to the two amplifiers and configured to provide an RF control signal that will be amplified by the two amplifiers such that an amplified RF control signal will be output at a second output of the output quadrature coupler; and a signal reflector connected to the second output of the output quadrature coupler and arranged to reflect the amplified RF control signal back to the second output of the output quadrature coupler. ### Claim 2 (depends on 1) The radio frequency power amplifier system according to claim 1, wherein the input quadrature coupler has a first input for receiving a RF input signal to be amplified; wherein the radio frequency control signal source is connected to a second input of the input quadrature coupler to provide the RF control signal to the second input of the input quadrature coupler such that the amplified RF control signal will be output at the second output of the output quadrature coupler. ### Claim 3 (depends on 2) The radio frequency power amplifier system according to claim 2, wherein the radio frequency control signal source is configured to provide the RF control signal with a frequency that is substantially the same as the RF input signal. ### Claim 4 (depends on 3) The radio frequency power amplifier system according to any claim 3, comprising: means to modify a phase and/or amplitude of the RF control signal and/or the amplified RF control signal. ### Claim 5 (depends on 4) The radio frequency power amplifier system according to claim 4, wherein the means to modify the phase and/or amplitude of the RF control signal and/or the amplified RF control signal comprises: a phase shifter to shift a phase of the RF control signal entering the second input of the input quadrature coupler. ### Claim 6 (depends on 5) The radio frequency power amplifier system according to claim 5, wherein the signal reflector comprises: a reactive load. ### Claim 7 (depends on 6) The radio frequency power amplifier system according to claim 6, wherein the reactive load is a tunable reactive load; and the radio frequency power amplifier system comprises: a controller connected to the tunable reactive load and configured to tune the reactive load to vary a phase of the reflected amplified RF control signal. ### Claim 8 (depends on 7) The radio frequency power amplifier system according to claim 7, wherein the tunable reactive load comprises: a switched capacitor network and/or switched inductor network. ### Claim 9 (depends on 8) The radio frequency power amplifier system according to claim 8, comprising: a signal generator having a first generator output and a second generator output, the signal generator including one or more processors configured to run a computer program that will cause the signal generator to: digitally generate an RF signal for output at the first generator output; and digitally generate the RF control signal for output at the second generator output. ### Claim 10 (depends on 9) The radio frequency power amplifier system according to claim 9, wherein the input quadrature coupler is implemented by the signal generator, the signal generator being configured to: digitally generate a first RF signal for output at the first generator output of the signal generator that corresponds to a desired signal at a first output of the input quadrature coupler for receipt by a first amplifier of the two amplifiers; and digitally generate a second RF signal for output at the second generator output of the signal generator that corresponds to a desired signal at a second output of the input quadrature coupler for receipt by a second amplifier of the two amplifiers. ### Claim 11 (depends on 1) The radio frequency power amplifier system according to claim 1, wherein the signal reflector comprises: a reactive load. ### Claim 12 (depends on 11) The radio frequency power amplifier system according to claim 11, wherein the reactive load is a tunable reactive load; and the radio frequency power amplifier system comprises: a controller connected to the tunable reactive load and configured to tune the reactive load to vary a phase of the reflected amplified RF control signal. ### Claim 13 (depends on 12) The radio frequency power amplifier system according to claim 12, wherein the tunable reactive load comprises: a switched capacitor network and/or switched inductor network. ### Claim 14 (depends on 13) The radio frequency power amplifier system according to claim 13, comprising: a signal generator having a first generator output and a second generator output, the signal generator including one or more processors configured to run a computer program that will cause the signal generator to: digitally generate an RF signal for output at the first generator output; and digitally generate the RF control signal for output at the second generator output. ### Claim 15 (depends on 14) The radio frequency power amplifier system according to claim 14, wherein the input quadrature coupler is implemented by the signal generator, the signal generator being configured to: digitally generate a first RF signal for output at the first generator output of the signal generator that corresponds to a desired signal at a first generator output of the input quadrature coupler for receipt by a first amplifier of the two amplifiers; and digitally generate a second RF signal for output at the second generator output of the signal generator that corresponds to a desired signal at a second generator output of the input quadrature coupler for receipt by a second amplifier of the two amplifiers. ### Claim 16 A method to modify and/or modulate an impedance at outputs of two amplifiers of a balanced amplifier arranged to amplify a radio frequency (RF) signal, the balanced amplifier having an output quadrature coupler, an amplified RF signal being outputted at a first output of the output quadrature coupler, the method comprising: using a radio frequency control signal source connected to the two amplifiers to provide a radio frequency (RF) control signal that is amplified by the two amplifiers of the balanced amplifier, such that an amplified RF control signal is outputted at a second output of the output quadrature coupler; and reflecting the amplified RF control signal outputted from the second output of the output quadrature coupler back to the second output of the output quadrature coupler. ### Claim 17 (depends on 16) The method of claim 16, comprising: inputting an RF input signal to be amplified into a first input of an input quadrature coupler of the balanced amplifier; and inputting an RF control signal into a second input of the input quadrature coupler to provide a RF control signal to the second input of the input quadrature coupler such that the amplified RF control signal is outputted at a second output of the output quadrature coupler. ### Claim 18 (depends on 17) The method according to claim 17, comprising: modifying a phase and/or amplitude of the RF control signal and/or the amplified RF control signal relative to the RF input signal.