Abstract: A high-frequency power amplifier is configured in such a way as to include an input matching circuit, an amplifying element, an output matching circuit, a coupling circuit, a detection circuit, and an output terminal, and in such a way that either the input matching circuit or the output matching circuit has an active element, the detection circuit receives a signal outputted by the coupling circuit and outputs a control voltage into which the detection circuit converts the signal to the active element, and the active element changes the impedance of the active element in accordance with the control voltage outputted by the detection circuit, thereby changing the power of a signal outputted by either the input matching circuit having the active element or the output matching circuit having the active element, to change the power of a signal which the coupling circuit outputs to the output terminal.

Abstract: A power supply modulation device includes a unit detecting, from a first digital signal, a first amplitude being the amplitude of a first analog signal provided to a first amplifier and detecting, from a second digital signal, a second amplitude being the amplitude of a second analog signal provided to a second amplifier; a unit that calculates a time differential value of a ratio of the first amplitude to a sum of the first amplitude and the second amplitude, and determines, on the basis of the time differential value, whether or not output impedance of a combining circuit that combines together the first analog signal amplified and the second analog signal changes along with a change in power of the combined signal; and a unit that controls a power supply voltage supplied to each of the first amplifier and the second amplifier, on the basis of the determination.

Abstract: A phase shifter includes: a first all-pass filter; a second all-pass filter; a first switching switch to provide a signal to either one of the first all-pass filter and the second all-pass filter; and a second switching switch to select the signal having passed through the first all-pass filter or the signal having passed through the second all-pass filter, wherein the first all-pass filter includes two inductors and three capacitors, and the second all-pass filter includes two inductors and three capacitors, or the first all-pass filter includes three inductors and two capacitors, and the second all-pass filter includes three inductors and two capacitors, and element values of elements included in the first all-pass filter and element values of elements included in the second all-pass filter are determined by impedance at which impedance matching is achieved, a frequency of the signal, and a variable.

Abstract: A Doherty amplifier is configured in such a way that a phase adjustment circuit adjusts either the phase of a return signal going to a first auxiliary amplification element as a result of passage of a first signal amplified by a second main amplification element through a second auxiliary amplification element as the return signal, or the phase of the return signal going to the second auxiliary amplification element as a result of reflection of the return signal by the first auxiliary amplification element, at a time of a backoff operation of the second auxiliary amplification element, in such a way that the sum of the phase of the return signal going to the first auxiliary amplification element and the phase of the return signal going to the second auxiliary amplification element is not equal to 0 degrees in the operating frequency band of the first signal.

Abstract: An amplifier circuit is configured in such a way that the amplifier circuit includes: a first amplifier to amplify a signal to be amplified; an output matching circuit through which the signal amplified by the first amplifier propagates; and a second amplifier to amplify the signal which has propagated through the output matching circuit, and the output matching circuit is a lumped constant circuit including multiple lumped constant elements, and, by using the multiple lumped constant elements, transforms the impedance seen on the second amplifier side from the first amplifier when the output power of the second amplifier is lower than saturation electric power, to impedance higher than impedance seen on the second amplifier side from the first amplifier when the output power of the second amplifier is equal to the saturation electric power.

Abstract: A Doherty amplifier includes: a first amplifier to amplify a first signal as an auxiliary amplifier in a case where a frequency of each of the first signal and a second signal is a first frequency, and amplify the first signal as a main amplifier in a case where the frequency of each of the first signal and the second signal is a second frequency; a second amplifier to amplify the second signal as a main amplifier in a case where the frequency of each of the first signal and the second signal is the first frequency, and amplify the second signal as an auxiliary amplifier in a case where the frequency of each of the first signal and the second signal is the second frequency; and a combiner to synthesize the first signal amplified by the first amplifier and the second signal amplified by the second amplifier.

Abstract: A power supply modulator includes: a first switching element in which a first voltage is applied to the first terminal and the second terminal is connected to an output terminal; a second switching element in which the third terminal is connected to the output terminal and the second terminal, and a second voltage is applied to the fourth terminal; a first driver circuit in which the first voltage is applied to the fifth terminal and the sixth terminal is grounded, to control opening and closing of the first switching element by a change in a resistance value between the fifth and sixth terminals; and a second driver circuit in which the seventh terminal is grounded and the second voltage is applied to the eighth terminal, to control opening and closing of the second switching element by a change in a resistance value between the seventh and eighth terminals.

Abstract: A Doherty amplifier includes: a first amplifying element to amplify a first signal; a second amplifying element to amplify a second signal having a phase difference with the first signal; a first transmission line connected to an output terminal of the first amplifying element; and a second transmission line connected to an output terminal of the second amplifying element, wherein the first transmission line and the second transmission line are equal to each other in characteristic impedance, the phase difference between the first signal and the second signal is not equal to a difference in electrical length between the second transmission line and the first transmission line, and the first signal having passed through the first transmission line and the second signal having passed through the second transmission line are subjected to different phase synthesis.

Abstract: A high-frequency amplifier includes: a common-source transistor that has gate fingers, drain fingers, and source fingers, amplifies a signal applied to each of the gate fingers as a signal to be amplified, and outputs an amplified signal from each of the drain fingers; a common-gate transistor that has source fingers connected to the drain fingers of the common-source transistor, drain fingers, and gate fingers, and amplifies the amplified signal output from each of the drain fingers of the common-source transistor; a gate bus bar connected to the gate fingers of the common-gate transistor; and capacitors each having a first end connected to the gate bus bar and a second end grounded: wherein the capacitors are arranged at respective positions where impedances obtained by looking toward the respective capacitors from the respective gate fingers of the common-gate transistor are equal to each other.

Abstract: A signal to be amplified is applied to a gate terminal of an amplifier element that amplifies the signal and that is a transistor, the bias circuit includes: a switching element having a first terminal and a second terminal, the first terminal being electrically connected to the gate terminal; and a trap compensation element having a third terminal and a fourth terminal, the third terminal being connected to the second terminal. Further, the bias circuit includes a control circuit to apply a bias voltage to the gate terminal. Further, the bias circuit includes a voltage application circuit to apply a first voltage to the fourth terminal when the signal to be amplified is a transmission signal, and apply a second voltage to the fourth terminal when the signal to be amplified is a reception signal, the second voltage being a negative voltage.

Abstract: A Doherty amplifier is configured in such a manner that: the ratio Z3/Z2 of a characteristic impedance Z3 of a second transmission line to a characteristic impedance Z2 of a first transmission line is a power division ratio P2/P3 of a signal to be amplified between a carrier amplifier and a peak amplifier when both of the carrier amplifier and the peak amplifier are saturated; and a resistance value Riso of a resistor is a value obtained by multiplying, by a proportionality coefficient w which is equal to or greater than 0 but less than 1, the sum of the input impedance Zcin0 of the carrier amplifier when the carrier amplifier reaches saturation and the input impedance Zpin0 of the peak amplifier when the peak amplifier reaches saturation.

Abstract: A Doherty amplifier includes: a transistor for a carrier amplifier; a transistor for a peak amplifier; a transmission line connected between an output terminal of the transistor for the carrier amplifier and an output terminal of the transistor for the peak amplifier; a stub that is connected in parallel to the output terminal of the transistor for the peak amplifier and that is capacitive and inductive in a working frequency band; and an output matching circuit connected to the output terminal of the transistor for the peak amplifier, the transmission line, and an output load, the output matching circuit to transform an impedance of the output load into an impedance lower than the impedance of the output load.

Abstract: In a semiconductor device including gate fingers each having a linear shape extending from a feed line, and arranged in areas between drain electrodes and source electrodes, open stubs are connected directly to the feed line.

Abstract: A Doherty amplifier includes: amplifiers including a main amplifier and an auxiliary amplifier; output circuits for increase in back-off amount including a first output circuit disposed between the main amplifier and an output combination unit provided by the amplifiers, and having a first electric length, and a second output circuit disposed between the auxiliary amplifier and the output combination unit, and having a second electric length; and a frequency characteristic compensation circuit for band broadening disposed electrically in parallel to the first output circuit, for compensating for the frequency characteristics of the impedances in the output circuits.

Abstract: This Doherty amplifier includes: a carrier amplifier for amplifying a first signal and outputting the amplified first signal; a peaking amplifier for amplifying a second signal and outputting the amplified second signal, the peaking amplifier having a non-linear output capacitance; a first output circuit for transmitting the first signal output from the carrier amplifier; a second output circuit for functioning as a virtual short stub when the peaking amplifier does not perform an amplification operation, and transmitting the second signal output from the peaking amplifier; and a combining circuit for combining the first signal transmitted by the first output circuit and the second signal transmitted by the second output circuit and outputting a combined signal of the first signal and the second signal, wherein, when the peaking amplifier performs the amplification operation, the second output circuit transforms an impedance seen by looking into the combining circuit from the peaking amplifier into an impedan

Abstract: A Doherty amplifier is configured to include a first transistor that amplifies a first signal and outputs the amplified first signal, a second transistor that amplifies a second signal and outputs the amplified second signal, and a combining circuit that combines the amplified first signal output from the first transistor and the amplified second signal output from the second transistor and outputs a combined signal of the amplified first signal and the amplified second signal, in which a signal mode in which the first signal amplified by the first transistor and the second signal amplified by the second transistor are combined in phase and a signal mode in which the first signal amplified by the first transistor and the second signal amplified by the second transistor are combined out of phase are switched in accordance with a frequency, and an operation mode is switched to a Doherty operation mode or an outphasing operation mode depending on the switched signal mode.

Abstract: Provided is an amplifier including: a first transistor connected to a signal input terminal; a second transistor connected to a signal output terminal; a wiring line configured to connect the first transistor and the second transistor to each other; and a variable inductor circuit which is electrically connected to the wiring line, and is grounded via a capacitor for DC current interruption, wherein the inductance value of the variable inductor circuit is set to an inductance value for canceling a parasitic capacitance between the first transistor and the second transistor.

Abstract: A high-frequency power amplifier is configured in such a way as to include an input matching circuit, an amplifying element, an output matching circuit, a coupling circuit, a detection circuit, and an output terminal, and in such a way that either the input matching circuit or the output matching circuit has an active element, the detection circuit receives a signal outputted by the coupling circuit and outputs a control voltage into which the detection circuit converts the signal to the active element, and the active element changes the impedance of the active element in accordance with the control voltage outputted by the detection circuit, thereby changing the power of a signal outputted by either the input matching circuit having the active element or the output matching circuit having the active element, to change the power of a signal which the coupling circuit outputs to the output terminal.

Abstract: Included is a compensation circuit having one end connected to another end of a first output circuit and another end of a second output circuit and another end grounded, the compensation circuit having an electrical length of 90 degrees at a first operation frequency and an electrical length of 45 degrees at a second operation frequency which is half of the first operation frequency.

Abstract: Gate fingers extending symmetrically from both sides of gate connecting portions, drain electrodes adjacent to both the gate fingers extending from both the sides of the gate connecting portions, and source electrodes respectively adjacent to the gate fingers extending from both the sides of the gate connecting portions are included. Gate air bridges connect the gate connecting portions and a gate routing line while straddling the source electrodes.