Asymmetric broadband Doherty power amplifier suitable for full frequency band of 5G low frequency band

Abstract

The invention relates to an asymmetric broadband Doherty power amplifier suitable for a full frequency band of a 5G low frequency band, and belongs to the technical field of wireless communication. The amplifier is composed of a power divider, a main power amplification branch, an auxiliary power amplification branch and a power synthesis network, wherein the main power amplification branch and the auxiliary power amplification branch respectively comprise an input and output offset line, a gate and drain bias network, and an input and an output matching network; the working bandwidth of the Doherty power amplifier is expanded by reducing an impedance transformation ratio of a quarter-wave impedance adjustment line and an impedance transformation line in the power synthesis network; and arequired broadband matching network is designed by a broadband impedance transformation network of a low-pass filter prototype, and the influence on an input matching network is reduced by using gatebias networks of antedisplacement primary and secondary power amplifiers. By adoption of the asymmetric broadband Doherty power amplifier provided by the invention, the working bandwidth of the Doherty power amplifier can be expanded.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, and relates to an asymmetric wideband Doherty power amplifier suitable for 5G low-frequency and full-frequency bands. Background technique [0002] The power amplifier is one of the core devices in the wireless transmitter, and its efficiency, power, linearity, bandwidth and other indicators have a decisive impact on the performance of the entire transmitter. In the current communication system, in order to improve the utilization rate of the spectrum, various complex modulation methods such as 4QAM, QPSK, OFDM, etc. are adopted, so that the modulated signal has a high peak-to-average ratio. The 4G-LTE modulated signal is used as the For example, the peak-to-average ratio of the modulated signal after peak elimination is still as high as 6-12dB. As a nonlinear device, the power amplifier will generate stronger nonlinear distortion when the signal with higher peak-to-average ratio ...

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Problems solved by technology

[0004] However, the power back-off range of 6dB obviously cannot meet the requirements of the current communication system. Therefore, in order to obtain a larger power back-off range, various improved Doherty power amplifier structures have emerged, among which the asymmetrical Doherty power The most widely used amplifier structure

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