Circuit for improving linearity and power added efficiency of power amplifier

Abstract

The invention discloses a circuit for improving the linearity and power added efficiency of a power amplifier. The power amplifier is in a Cascode structure formed by overlapping a grounded-emitter transistor and a grounded-base transistor in series; a first secondary harmonic resonance network for suppressing secondary harmonic signals is connected between the collector of the grounded-emitter transistor and the ground; a second secondary harmonic resonance network for suppressing secondary harmonic signal output is connected between the collector of the grounded-base transistor and the ground; and a third harmonic resonance network for reflecting third harmonic signals to the collector is connected between the collector of the grounded-base transistor and the output port. The invention adopts the resonance networks for respectively processing the fundamental harmonic, the secondary harmonic and the third harmonic, thereby achieving the purposes of smoothly passing the fundamental harmonic, short circuiting the secondary harmonic to the ground and obstructing the third harmonic to be overlaid with the fundamental harmonic, and improving the linearity and the power added efficiency of the power amplifier.

Description

technical field [0001] The invention relates to a circuit for improving linearity and power-added efficiency of a power amplifier. Background technique [0002] The power amplifier is one of the most nonlinear devices in the communication system. Its nonlinear distortion will cause the spectrum expansion of the wireless communication system to interfere with adjacent channel signals and deteriorate the bit error rate, reduce the data rate of the system and reduce the capacity of the system. Increasing the system channel frequency spacing reduces the spectrum utilization of the system. In addition, for the whole system, the power amplifier itself has a large power consumption, which accounts for more than 60% of the system power consumption. Reducing the power consumption of the power amplifier is helpful for prolonging the system use time, reducing power consumption, and reducing system volume and weight. etc. play a key role. Therefore, designing a power amplifier with hi...

AI Technical Summary

Problems solved by technology

LINC is very sensitive to the gain and phase difference on the two paths, any matching error of gain and phase will lead to incomplete elimination of distorted signal, seriously affecting the linearity of the system

The difficulty of matching gain and phase makes LINC still rarely used

The disadvantage of EE&R is that the accuracy and performance of the modulation change with time and temperature. Factors such as AM (amplitude modulation) and PM (phase modulation) of the modulator will affect the distortion output product of the amplifier, and additional high-order products will be generated.

Although the Doherty power amplifier has high efficiency, its linearity is poor

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