High frequency power amplifier with high efficiency and low distortion

Claim 2

A high frequency amplifier comprising: a constant envelope signal generation circuit (21) for receiving an input electric signal, and transforming the electric signal to form two constant envelope signals where amplitudes of envelopes of the constant envelope signals are constant, and phases of the constant envelope signals correspond to an amplitude of an envelope of the input electric signal; first and second amplifying circuits (22, 23) for respectively receiving said two constant envelope signals, and amplifying the constant envelope signals, separately, to respectively generate first and second amplified signals; and a power synthesizing circuit for synthesizing said first and second amplified signals to generate an amplified signal of said input electric signal, and reflecting remaining components of said first and second amplified signals which remaining components remain in said synthesizing operation, toward said first and second amplifying circuits (22, 23).

Claim 3

A high frequency amplifier according to claim 1, wherein said power synthesizing circuit has one output terminal, two input terminals, and two electric signal paths respectively connecting said two input terminals to said output terminal; said first and second amplifying circuits each comprising an amplification device; and a propagation length of an electric signal from an output terminal of each amplification device to said output terminal of said power synthesizing circuit is equal to (2n-1)X/4, where n=1, 2, ... , and 27r/>.. is an amplification frequency.

Claim 4

A high frequency amplifier comprising: a constant envelope signal generation circuit (21) for receiving an input electric signal, and transforming the electric signal to form first and second constant envelope signals where amplitudes of envelopes of the first and second constant envelope signals are constant, and phases of the first and second constant envelope signals correspond to an amplitude of an envelope of the input electric signal; a phase shift means (27) for shifting a phase of said first constant envelope signal by 90 degrees; a first amplifying circuit (22) for receiving and amplifying said first constant envelope signal after the phase of the first constant envelope signal has been shifted by 90 degrees, to generate a first amplified signal; a second amplifying circuit (23) for receiving and amplifying said second constant envelope signal, to generate a second amplified signal; and a 90 hybrid circuit (26), having first, second, third, and fourth terminals, for receiving said first and second amplified signals at said first and second terminals of thereof, respectively, and synthesizing said first and second amplified signals to generate an amplified signal of said input electric signal, where a propagation length of a first signal path from said second terminal to said third terminal, and a propagation length of a second signal path from said second terminal to said third terminal, are made so that a sum of said phase shift caused by said phase shift means (27) and a phase shift caused in the first signal path from said first terminal to said third terminal, is equal to a phase shift caused in the second signal path from said second terminal to said third terminal, said amplified signal of said input electric signal is output from said third terminal, and said fourth terminal is made electrically open.

Claim 5

A high frequency amplifier comprising: a constant envelope signal generation circuit (21) for receiving an input electric signal, and transforming the electric signal to form first and second constant envelope signals where amplitudes of envelopes of the first and second constant envelope signals are constant, and phases of the first and second constant envelope signals correspond to an amplitude of an envelope of the input electric signal; a phase shift means (27) for shifting a phase of said first constant envelope signal by 90 degrees; a first amplifying circuit (22) for receiving and amplifying said first constant envelope signal after the phase of the first constant envelope signal has been shifted by 90 degrees, to generate a first amplified signal; a second amplifying circuit (23) for receiving and amplifying said second constant envelope signal, to generate a second amplified signal; and a 90 hybrid circuit (26), having first, second, third, and fourth terminals, for receiving said first and second amplified signals at said first and second terminals of thereof, respectively, and synthesizing said first and second amplified signals to generate an amplified signal of said input electric signal, where a propagation length of a first signal path from said second terminal to said third terminal, and a propagation length of a second signal path from said second terminal to said third terminal, are made so that a sum of said phase shift caused by said phase shift means (27) and a phase shift caused in the first signal path from said first terminal to said third terminal, is equal to a phase shift caused in the second signal path from said second terminal to said third terminal, said amplified signal of said input electric signal is output from said third terminal, and said fourth terminal is made electrically open.

Claim 6

A high frequency amplifier comprising: a constant envelope signal generation circuit (21) for receiving an input electric signal, and transforming the electric signal to form first and second constant envelope signals where amplitudes of envelopes of the first and second constant envelope signals are constant, and phases of the first and second constant envelope signals correspond to an amplitude of an envelope of the input electric signal; a phase shift means (27') for shifting a phase of said first constant envelope signal by 180 degrees; a first amplifying circuit (22) for receiving and amplifying said first constant envelope signal after the phase of the first constant envelope signal has been shifted by 180 degrees, to generate a first amplified signal; a second amplifying circuit (23) for receiving and amplifying said second constant envelope signal, to generate a second amplified signal; and a 180° hybrid circuit (28), having first, second, third, and fourth terminals, for receiving said first and second amplified signals at said first and second terminals of thereof, respectively, and synthesizing said first and second amplified signals to generate an amplified signal of said input electric signal, where a propagation length of a first signal path from said second terminal to said third terminal, and a propagation length of a second signal path from said second terminal to said third terminal, are made so that a sum of said phase shift caused by said phase shift means (27') and a phase shift caused in the first signal path from said first terminal to said third terminal, is equal to a phase shift caused in the second signal path from said second terminal to said third terminal, said amplified signal of said input electric signal is output from said third terminal, and said fourth terminal is made electrically open.

Claim 7

A high frequency amplifier comprising: a constant envelope signal generation circuit (21) for receiving an input electric signal, and transforming the electric signal to form first and second constant envelope signals where amplitudes of envelopes of the first and second constant envelope signals are constant, and phases of the first and second constant envelope signals correspond to an amplitude of an envelope of the input electric signal; a phase shift means (27') for shifting a phase of said first constant envelope signal by 180 degrees; a first amplifying circuit (22) for receiving and amplifying said first constant envelope signal after the phase of the first constant envelope signal has been shifted by 180 degrees, to generate a first amplified signal; a second amplifying circuit (23) for receiving and amplifying said second constant envelope signal, to generate a second amplified signal; and a 180° hybrid circuit (28), having first, second, third, and fourth terminals, for receiving said first and second amplified signals at said first and second terminals of thereof, respectively, and synthesizing said first and second amplified signals to generate an amplified signal of said input electric signal, where a propagation length of a first signal path from said second terminal to said third terminal, and a propagation length of a second signal path from said second terminal to said third terminal, are made so that a sum of said phase shift caused by said phase shift means (27') and a phase shift caused in the first signal path from said first terminal to said third terminal, is equal to a phase shift caused in the second signal path from said second terminal to said third terminal, said amplified signal of said input electric signal is output from said third terminal, and said fourth terminal is made electrically open.

Claim 8

A high frequency amplifier according to one of claims 1 to 4, wherein said first and second amplifying circuits (22, 23) are each one of a class "AB" amplifier, a class "B" amplifier, a class "C" amplifier, and a class "F" amplifier, wherein a current which flows therethrough varies depending upon an output power thereof.

Claim 9

A high frequency amplifier comprising: a constant envelope signal generation circuit (21) for receiving an input electric signal, and transforming the electric signal to form two constant envelope signals where amplitudes of envelopes of the constant envelope signals are constant, and phases of the constant envelope signals correspond to an amplitude of an envelope of the input electric signal; first and second amplifying circuits (22, 23) for respectively receiving said two constant envelope signals, and amplifying the constant envelope signals, separately, to respectively generate first and second amplified signals; and a first circulator (10), provided corresponding to said first amplifying circuits (22), having first, second, and third terminals, said first terminal is connected to an output terminal of said first amplifying circuit (22); a second circulator (10), provided corresponding to said second amplifying circuits (23), having second, second, and third terminals, said second terminal is connected to an output terminal of said second amplifying circuit (22); in each of said first and second circulators (10, 11), an input signal from said first terminal being output from said second terminal, an input signal from said second terminal being output from said third terminal, and an input signal from said third terminal being output from said first terminal; a power synthesizing circuit (24, 25) for receiving said first and second amplified signals from said second terminals of said first and second circulators, synthesizing the received signals to generate an amplified signal of said input electric signal, and reflecting remaining components of said first and second amplified signals which remaining components remain in said synthesizing operation, toward said second terminals of said first and second circulators (10, 11); a propagation length of an electric signal from an output terminal of each of said first and second circulators (10, 11) to said output terminal of said power synthesizing circuit (24, 25) is equal to (2n-1)x4, where n = 1, 2, ... , and 27r/>.. is an amplification frequency; a first phase shift means (41) connected to said third terminals of said first circulator, for receiving an electric signal which is output from the third terminal, shifting a phase of the received electric signal, and inputting the phase-shifted signal into the third terminal; and a second phase shift means (42) connected to said third terminals of said second circulator, for receiving an electric signal which is output from the third terminal, shifting a phase of the received electric signal, and inputting the phase-shifted signal into the third terminal.

Claim 10

A high frequency amplifier comprising: a constant envelope signal generation circuit (21) for receiving an input electric signal, and transforming the electric signal to form two constant envelope signals where amplitudes of envelopes of the constant envelope signals are constant, and phases of the constant envelope signals correspond to an amplitude of an envelope of the input electric signal; first and second amplifying circuits (22, 23) for respectively receiving said two constant envelope signals, and amplifying the constant envelope signals, separately, to respectively generate first and second amplified signals; and a first circulator (10), provided corresponding to said first amplifying circuits (22), having first, second, and third terminals, said first terminal is connected to an output terminal of said first amplifying circuit (22); a second circulator (10), provided corresponding to said second amplifying circuits (23), having second, second, and third terminals, said second terminal is connected to an output terminal of said second amplifying circuit (22); in each of said first and second circulators (10, 11), an input signal from said first terminal being output from said second terminal, an input signal from said second terminal being output from said third terminal, and an input signal from said third terminal being output from said first terminal; a power synthesizing circuit (24, 25) for receiving said first and second amplified signals from said second terminals of said first and second circulators, synthesizing the received signals to generate an amplified signal of said input electric signal, and reflecting remaining components of said first and second amplified signals which remaining components remain in said synthesizing operation, toward said second terminals of said first and second circulators (10, 11); a propagation length of an electric signal from an output terminal of each of said first and second circulators (10, 11) to said output terminal of said power synthesizing circuit (24, 25) is equal to (2n-1)x4, where n = 1, 2, ... , and 27r/>.. is an amplification frequency; a first phase shift means (41) connected to said third terminals of said first circulator, for receiving an electric signal which is output from the third terminal, shifting a phase of the received electric signal, and inputting the phase-shifted signal into the third terminal; and a second phase shift means (42) connected to said third terminals of said second circulator, for receiving an electric signal which is output from the third terminal, shifting a phase of the received electric signal, and inputting the phase-shifted signal into the third terminal.

Claim 11

A high frequency amplifier according to claim 6, wherein the absolute values of the phase shifts in said first and second phase shift means (41, 42) are equal, and the polarities of the phase shifts in said first and second phase shift means (41, 42) are contrary from one another.

Claim 12

A high frequency amplifier comprising: a constant envelope signal generation circuit (21) for receiving an input electric signal, and transforming the electric signal to form two constant envelope signals where amplitudes of envelopes of the constant envelope signals are constant, and phases of the constant envelope signals correspond to an amplitude of an envelope of the input electric signal; first and second amplifying circuits (22, 23) for respectively receiving said two constant envelope signals, and amplifying the constant envelope signals, separately, to respectively generate first and second amplified signals; and a power synthesizing circuit for receiving said first and second amplified signals, and synthesizing the received signals to generate an amplified signal of said input electric signal; said power synthesizing circuit comprising a means for adaptively varying a real part of an input impedance of the power synthesizing circuit responding to an amplitude of an envelope of said input electric signal so that the real part becomes large when an output power is small, and the real part becomes small when an output power is large.

Claim 13

A high frequency amplifier comprising: a constant envelope signal generation circuit (21) for receiving an input electric signal, and transforming the electric signal to form two constant envelope signals where amplitudes of envelopes of the constant envelope signals are constant, and phases of the constant envelope signals correspond to an amplitude of an envelope of the input electric signal; first and second amplifying circuits (22, 23) for respectively receiving said two constant envelope signals, and amplifying the constant envelope signals, separately, to respectively generate first and second amplified signals; and a power synthesizing circuit for receiving said first and second amplified signals, and synthesizing the received signals to generate an amplified signal of said input electric signal; said power synthesizing circuit comprising a means for adaptively varying a real part of an input impedance of the power synthesizing circuit responding to an amplitude of an envelope of said input electric signal so that the real part becomes large when an output power is small, and the real part becomes small when an output power is large.

Claim 14

A high frequency amplifier according to claim 8, wherein said power synthesizing circuit comprises, an input power level detecting means (33) for detecting a power level of said input electric signal; a first circulator (10), provided corresponding to said first amplifying circuits (22), having first, second, and third terminals, said first terminal is connected to an output terminal of said first amplifying circuit (22); a second circulator (11), provided corresponding to said second amplifying circuits (23), having second, second, and third terminals, said second terminal is connected to an output terminal of said second amplifying circuit (23); in each of said first and second circulators (10, 11), an input signal from said first terminal being output from said second terminal, an input signal from said second terminal being output from said third terminal, and an input signal from said third terminal being output from said first terminal; a branch circuit (24, 25) for receiving said first and second amplified signals from said second terminals of said first and second circulators, synthesizing the received signals to generate an amplified signal of said input electric signal, and reflecting remaining components of said first and second amplified signals which remaining components remain in said synthesizing operation, toward said second terminals of said first and second circulators (10, 11 ); a propagation length of an electric signal from an output terminal of each of said first and second circulators (10, 11) to said output terminal of said branch circuit (24, 25) is equal to (2n-1)λ/4, where n = 1, 2, ... , and 2π/λ is an amplification frequency; a first phase shift means (47) connected to said third terminals of said first circulator, for receiving an electric signal which is output from the third terminal, shifting a phase of the received electric signal, and inputting the phase-shifted signal into the third terminal; and a second phase shift means (48) connected to said third terminals of said second circulator, for receiving an electric signal which is output from the third terminal, shifting a phase of the received electric signal, and inputting the phase-shifted signal into the third terminal; said branch circuit (24, 25) comprising a means for adaptively varying a real part of an input impedance the the power synthesizing circuit responding to a detected result of said input power level detecting means (33) so that said real part is maintained equal to zero.

Claim 15

A high frequency amplifier comprising: a constant envelope signal generation circuit (21) for receiving an input electric signal, and transforming the electric signal to form two constant envelope signals where amplitudes of envelopes of the constant envelope signals are constant, and phases of the constant envelope signals correspond to an amplitude of an envelope of the input electric signal; a phase inversion means (37) for inverting a phase of one of said two constant envelope signals; and a single-ended push-pull amplifier circuit (36) for receiving the other of said two constant envelope signals, and an output of said phase inversion means (37), and synthesizing the received signals to generate an amplified signal of said input electric signal.

Claim 16

A high frequency amplifier comprising: a constant envelope signal generation circuit (21) for receiving an input electric signal, and transforming the electric signal to form two constant envelope signals where amplitudes of envelopes of the constant envelope signals are constant, and phases of the constant envelope signals correspond to an amplitude of an envelope of the input electric signal; a phase inversion means (37) for inverting a phase of one of said two constant envelope signals; and a single-ended push-pull amplifier circuit (36) for receiving the other of said two constant envelope signals, and an output of said phase inversion means (37), and synthesizing the received signals to generate an amplified signal of said input electric signal.

Claim 17

A high frequency amplifier according to claim 10, wherein said single-ended push-pull amplifier circuit (36) comprises first and second amplifying devices being serially connected, and said first and second amplifying devices are each one of a class "AB" amplifier, a class "B" amplifier, and a class "C" amplifier, wherein a current which flows therethrough varies depending upon an input power thereof.