Abstract: A Doherty amplifier includes: a carrier amplifier that amplifies a first signal; a peak amplifier that amplifies a second signal; and a synthesis circuit that synthesizes the first signal amplified by the carrier amplifier and the second signal amplified by the peak amplifier, and the synthesis circuit includes a bandpass filter circuit that includes parasitic capacitances at respective output sides of the carrier amplifier and the peak amplifier as capacitors.

Abstract: A Doherty amplifier includes: a first filter circuit to output a first input signal obtained by attenuating an input signal lying in a first frequency band, and to output a second input signal obtained by allowing passage of an input signal lying in a second frequency band; a second filter circuit to output a third input signal obtained by attenuating an input signal lying in the first frequency band, and to output a fourth input signal obtained by attenuating an input signal lying in the second frequency band; a first amplifier to operate as an auxiliary amplifier when receiving the first input signal, and to operate as a main amplifier when receiving the second input signal; and a second amplifier tip operate as the main amplifier when receiving the third input signal, and to operate as the auxiliary amplifier when receiving the fourth input signal.

Abstract: A digital-to-analog converter includes a plurality of 1-bit elements each of which outputs a current corresponding to a value indicated by a digital signal when the digital signal is input; and a capacitive load connected to the plurality of 1-bit elements, the digital-to-analog converter being configured to generate an analog voltage waveform via the capacitive load that receives currents output from the plurality of 1-bit elements, wherein each of the 1-bit elements includes a switching circuit to change a bias of a voltage in each of the 1-bit elements according to a value indicated by an input digital signal, and to switch connection and non-connection with a power supply according to a change in the bias.

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 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: 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: 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 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 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 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: 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: 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: 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: 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: An apparatus includes an envelope detecting unit for detecting an envelope of a signal to be amplified, and a variable power supply applies, to an output terminal of a carrier amplifier, a voltage increased with increase in the envelope detected by the envelope detecting unit. As a result, highly efficient operation can be implemented without including a phase shifter including a quarter wavelength line or the like.

Abstract: Parallel inductors include a first metal wire (8a or 8b) for connecting a drain terminal (2) and a first metal pattern (7a or 7b), and a second metal wire (10a or 10b) for connecting the first metal pattern (7a or 7b) and a second metal pattern (9a or 9b). The second metal wires (10a and 10b) are each positioned between the corresponding first metal wire (8a or 8b) and a corresponding third metal wire (12a or 12b) for connecting the drain terminal (2) and a third metal pattern (11). The direction of current through the second metal wires (10a and 10b) is opposite to the direction of current through each of the first metal wire (8a or 8b) and the third metal wire (12a or 12b).

Abstract: Included is a compensation circuit (9) having one end connected to another end of a first output circuit (7) and another end of a second output circuit (8) 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: In a Doherty amplifier including a carrier amplifier (6) and a peaking amplifier (8) connected in parallel with each other, a compensation circuit (9) for causing an impedance seen from an output end (9a) of the compensation circuit (9) toward the peaking amplifier (8) to be open within a used frequency range and compensating for frequency dependence of an impedance seen from an output of a combiner (10) toward the combiner (10) in a state in which the peaking amplifier (8) is not operating is arranged between the peaking amplifier (8) and the combiner (10). This achieves a wider bandwidth without making the circuit larger in size and more complicated.

Abstract: Provided is a load modulation amplifier including: a high frequency circuit board; and on the board, an input distribution circuit unit (DC) including: a distributor for dividing one input signal into two signals IS1 and IS2; and a phase delay circuit formed on a signal line for the divided IS2; a carrier amplifier (CA) including a first high frequency transistor for amplifying the IS1; a peak amplifier (PA) including a second high frequency transistor and for amplifying the IS2; and an output combination circuit (OCCU) including: a 90-degree phase delay circuit (90DC) formed on a signal line for output of the CA; a combiner for combining output of the 90DC and output of the PA; and an impedance conversion circuit for converting an output impedance of the combiner. The CA and the PA are directly connected to the OCCU without converting an output impedance.

Abstract: A distributor distributes an input signal to a first transmission line and a second transmission line. A high-pass filter, a first linearizer, and a first phase shifter disposed on the first transmission line adjust the phase and amplitude of an intermodulation distortion in a low-frequency range. A low-pass filter, a second linearizer, and a second phase shifter disposed on the second transmission line adjust the phase and amplitude of an intermodulation distortion in a high-frequency range. A synthesizer synthesizes the signal from the first transmission line and the signal from the second transmission line.