Abstract: A power amplifier including: a main power amplification device having an output; an auxiliary power amplification device having an output; a load modulation circuit operably connected to the output of the main power amplification device and the output of the auxiliary power amplification device; and a post-matching circuit operably connected to load modulation circuit. The load modulation circuit is arranged to enable fundamental frequency load modulation and to enable modulated harmonic terminations of at least the second and third harmonic frequencies. The modulated harmonic terminations may include drain terminations.

Abstract: A power amplifier circuit includes a first impedance transformer circuit arranged to connect with a carrier device, and a second impedance transformer circuit arranged to connect with a peaking device. Both the first and the second impedance transformer circuit include a parallel impedance transformer arrangement.

Abstract: The present invention provides a wideband Doherty power amplifier comprising: a main power amplification device; an auxiliary power amplification device arranged in parallel with the main power amplification device; and a coupled phase compensation network configured for compensating a phase shift between the main power amplification device and the auxiliary power amplification device. The phase compensation network comprising a first transmission line section; a second transmission line section extending substantially collinearly with the first transmission line section; and two pairs of end-connected coupled transmission lines connected in parallel between the first transmission line section and the second transmission line section. The provided Doherty power amplifier demonstrated operation at 6 dB back-off between 1.3-2.3 GHz with efficiency in excess of 41%, which can be used in modern and future wireless communication systems which require power amplifiers operating over a wide frequency range.

Abstract: A power amplifier circuit includes a first impedance transformer circuit arranged to connect with a carrier device, and a second impedance transformer circuit arranged to connect with a peaking device. Both the first and the second impedance transformer circuit include a parallel impedance transformer arrangement.

Abstract: A power amplifier including: a main power amplification device having an output; an auxiliary power amplification device having an output; a load modulation circuit operably connected to the output of the main power amplification device and the output of the auxiliary power amplification device; and a post-matching circuit operably connected to load modulation circuit. The load modulation circuit is arranged to enable fundamental frequency load modulation and to enable modulated harmonic terminations of at least the second and third harmonic frequencies. The modulated harmonic terminations may include drain terminations.

Abstract: A Doherty power amplifier having a main power amplification device and an auxiliary power amplification device arranged in parallel with the main power amplification device includes a load modulation circuit having a harmonic injection circuit connected with respective outputs of the main power amplification device and the auxiliary power amplification device. The harmonic injection circuit is arranged to provide a phase shift to simultaneously modulate transfer of second harmonic components generated at the main power amplification device to the auxiliary power amplification device and transfer of second harmonic components generated at the auxiliary power amplification device to the main power amplification device, when the main power amplification device and the auxiliary power amplification device are operated at saturation.

Abstract: A Doherty power amplifier having a main power amplification device and an auxiliary power amplification device arranged in parallel with the main power amplification device includes a load modulation circuit having a harmonic injection circuit connected with respective outputs of the main power amplification device and the auxiliary power amplification device. The harmonic injection circuit is arranged to provide a phase shift to simultaneously modulate transfer of second harmonic components generated at the main power amplification device to the auxiliary power amplification device and transfer of second harmonic components generated at the auxiliary power amplification device to the main power amplification device, when the main power amplification device and the auxiliary power amplification device are operated at saturation.

Abstract: A Doherty power amplifier includes a main device in a main amplifier circuit and an auxiliary device in an auxiliary amplifier circuit arranged in parallel with the main amplifier circuit. The Doherty power amplifier further includes a load modulation network including a first open-circuited transmission line connected to an output of the main device; a second open-circuited transmission line connected to an output of the auxiliary device; and an impedance transformation and phase compensation network connected with the output of the main device and the output of the auxiliary device for providing a combined output power. The first and second open-circuited transmission lines are arranged directly adjacent one another to form, during operation, a mutual coupling therebetween.

Abstract: Aspects describe a wideband active quasi-circulator that has the advantages of small size, lightweight, and compatibility with monolithic microwave integrated circuit (MMIC) technology. An active quasi-circulator is provided that comprises both a power amplifier and a low noise amplifier. The active quasi-circulator can operate over a wide frequency range with isolation or substantial isolation between a power amplifier and a low noise amplifier that is tunable with isolation or substantial isolation at any frequency within the wide frequency range. The provided quasi-circulator is suitable for use in mobile units in multi-band radio frequency communication systems, as well as in other configurations.

Abstract: Aspects describe a wideband active quasi-circulator that has the advantages of small size, lightweight, and compatibility with monolithic microwave integrated circuit (MMIC) technology. An active quasi-circulator is provided that comprises both a power amplifier and a low noise amplifier. The active quasi-circulator can operate over a wide frequency range with isolation or substantial isolation between a power amplifier and a low noise amplifier that is tunable with isolation or substantial isolation at any frequency within the wide frequency range. The provided quasi-circulator is suitable for use in mobile units in multi-band radio frequency communication systems, as well as in other configurations.

Abstract: A biasing circuit is used to provide low distortion and high efficiency operation of a microwave power amplifier. The biasing circuit utilizes the nonlinear rectified current of a microwave diode or transistor for biasing the amplifying transistor self-adaptively. The biasing current not only reduces the DC bias power during low-power operation and increases self-adaptively during high-power operation, but also manipulates the intermodulation distortion minimum dynamically. Meanwhile, the biasing circuit distorts the input signals with positive gain and negative phase deviations. Therefore, the average power efficiency of the operation is enhanced, the linearity of the input-output characteristic is improved and the radiated level of adjacent channel power is suppressed.

Abstract: A biasing circuit is used to provide low distortion and high efficiency operation of a microwave power amplifier. The biasing circuit utilizes the nonlinear rectified current of a microwave diode or transistor for biasing the amplifying transistor self-adaptively. The biasing current not only reduces the DC bias power during low-power operation and increases self-adaptively during high-power operation, but also manipulates the intermodulation distortion minimum dynamically. Meanwhile, the biasing circuit distorts the input signals with positive gain and negative phase deviations. Therefore, the average power efficiency of the operation is enhanced, the linearity of the input-output characteristic is improved and the radiated level of adjacent channel power is suppressed.