Broadband dual-band three-way Doherty power amplifier adopting combined output network

Abstract

The invention discloses a broadband dual-band three-way Doherty power amplifier adopting a combined output network. The power amplifier comprises a power divider, a carrier phase compensation line, acarrier amplification circuit, a dual-band carrier output matching network, a first peak amplification circuit, a second peak amplification circuit, the combined output network and a rear matching network. According to the invention, the bandwidth can be effectively expanded; in an asymmetric double-channel Doherty power amplifier, the output impedance of a single peak amplifier is greatly influenced by the frequency range, so the combined output network is adopted, the required high output impedance is provided for the carrier amplifier on two frequency bands in a fallback state, and the bandwidth of the Doherty power amplifier can be expanded; due to the fact that the second harmonic control network is introduced into the post-matching network, fundamental wave and harmonic load impedance of the carrier amplifier can better meet the requirements of the continuous inverse class F power amplifier, and therefore the drain electrode efficiency in the back-off and saturation state is improved.

Description

technical field [0001] The invention relates to the technical field of communication, in particular to a broadband dual-band 3-way Doherty power amplifier using a combined output network. Background technique [0002] Future wireless communication systems will require higher and higher data transmission rates, resulting in a significant increase in the peak-to-average power ratio of modulated signals. The Doherty power amplifier is widely used because of its simple structure and can significantly improve the efficiency of the amplifier during power back-off. In order to further improve the efficiency, the academic circles proposed harmonically controlled Doherty amplifiers based on F-class and J-class modes. Due to the symmetrical configuration, the power back-off range of traditional harmonic control Doherty power amplifiers is always limited to about 6dB, which cannot meet the requirements of modern communication systems. However, in the 5G communication system that is g...

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Problems solved by technology

However, on the one hand, at low power (the peak amplifier is in the cut-off state), due to the phase dispersion effect of the peak output matching network, the output impedance Z in a wide frequency band P1,OUT There is a large difference between low frequency and high frequency, and the output impedance Z' after being converted to the junction point by a quarter-wavelength impedance transformation line P1,OUT It will not be completely guaranteed to be near the open circuit point, and the lower output impedance Z' at low frequency and high frequency P1,OUT It will affect the performance of the carrier amplifier and affect the expansion of the working bandwidth

On the other hand, when high-power transistors are used to design peak amplifiers, the optimal load of high-power transistors is relatively small, which makes it difficult to design peak output matching networks and achieve wider operating bandwidths.

[0005] Therefore, the asymmetric dual-channel Doherty power amplifier cannot meet modern high-bandwidth and high-efficiency requirements

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