Post-Distortion Linearization Doherty Power Amplifier Based on Ferroelectric Capacitor

Abstract

The invention discloses a post-distortion linearized Doherty power amplifier based on a ferroelectric capacitor. The power amplifier comprises a main power amplification module and an auxiliary power amplification module which are connected in parallel, wherein input ends of the main power amplification module and the auxiliary power amplification module are taken as a total input end of the Doherty power amplifier; a phase shift module is connected in series between the input end of the auxiliary power amplification module and a part input end; a phase shift module is connected in parallel between an output end of the main power amplification module and an output end of the auxiliary module; the output end of the main power amplification module is compensated by the phase shift module and then synthesized with the output end of the auxiliary power amplification module to form total output; the ferroelectric capacitor is connected in series between the input end of the auxiliary power amplification module and the phase shift module; and the ferroelectric capacitor is connected to an adjustable direct-current bias voltage. The power amplifier disclosed by the invention is characterized in that the direct-current bias voltage of the ferroelectric capacitor is changed, so that source-pull matching of the auxiliary power amplification module can be adjusted, and thus gain-compression distortion compensation can be implemented to main power amplification output.

Description

technical field [0001] The invention relates to the field of microwave circuit design, in particular to a high-linearity Doherty power amplifier based on post-distortion technology of a ferroelectric capacitor structure. Background technique [0002] With the development and continuous improvement of wireless communication, many modulation methods have higher and higher requirements for peak-to-average ratio, so the linearity of the power amplifier is becoming more and more important. In order to obtain higher linearity, power amplifier back-off and feed-forward are usually used And other methods, these methods will lead to lower efficiency and complex structure of the power amplifier. In the Doherty (Doherty) power amplifier scheme, it is difficult to obtain high efficiency and good linearity at the same time. [0003] At present, in domestic and foreign research in this direction, pre-distortion is usually used to improve Doherty linearity while maintaining high efficienc...

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Problems solved by technology

[0002] With the development and continuous improvement of wireless communication, many modulation methods have higher and higher requirements for peak-to-average ratio, so the linearity of the power amplifier is becoming more and more important. In order to obtain higher linearity, power amplifier back-off and feed-forward are usually used and other methods, these methods will lead to lower efficiency and complex structure of the power amplifier

In the Doherty (Doherty) power amplifier scheme, it is difficult to obtain high efficiency and good linearity at the same time

[0003] At present, in domestic and foreign research in this direction, pre-distortion is usually used to improve Doherty linearity while maintaining high efficiency. However, pre-distortion technology requires a large number of digital circuits to cooperate, and microwave circuits and intermediate frequency circuits are also prone to signal generation. crosstalk, and the structure is relatively complex, the use in the current wireless system base station will be greatly restricted

Under high power conditions, the gain compression distortion of the main power amplifier in the Doherty power amplifier cannot be solved, which largely restricts the improvement of the linearity of the Doherty power amplifier

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