Power Amplifier Linearity Using CRLH Harmonic Suppression
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Solution Overview
Problem
Power amplifiers in wireless communication systems face challenges with non-linearity, leading to harmonic and intermodulation distortion, which affects the transmission and reception of RF signals, making normal communication difficult.
Innovation Solution
The integration of a predistortion unit and matching units with a composite right/left-handed (CRLH) structure, including input and output matching units with meta electromagnetic wave characteristics, to suppress harmonic components and intermodulation distortion, thereby improving linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional power amplifier is used to amplify RF signals, then output power gain is achieved, but harmonic distortion and intermodulation distortion occur due to non-linearity
Solution Approach 1:
The predistortion unit pre-processes the input signal by applying inverse non-linear characteristics before the signal enters the power amplifier. This preliminary action compensates for the amplifier's non-linearity, causing the amplifier's non-linear distortion to cancel out the predistortion effects, thereby achieving linear output without requiring post-processing filtering
Solution Approach 2:
The CRLH matching unit acts as an intermediary component between the predistortion unit and the power amplifier, and between the power amplifier and the output. This matching unit provides impedance transformation and harmonic suppression, mediating the signal transmission while filtering out harmful harmonic components generated by the amplifier's non-linearity
2Power
If the amplifier operates at high power levels, then output power is improved, but non-linearity increases causing communication errors
Solution Approach 1:
The predistortion unit applies pre-compensation to the input signal at high power levels, anticipating and counteracting the amplifier's non-linear behavior. This allows the amplifier to operate at high power while maintaining signal fidelity and communication reliability through the pre-applied linearization
3Ease of manufacture
If matching units with traditional structures are used, then impedance matching is achieved, but harmonic suppression is insufficient
Solution Approach 1:
The CRLH matching unit employs a composite structure combining right-handed and left-handed transmission line elements. This composite configuration creates frequency-selective characteristics that provide both broadband impedance matching and effective harmonic suppression, achieving dual functionality that traditional single-structure matching networks cannot provide
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively suppresses second and third harmonic components and intermodulation distortion, enhancing the linearity of power amplifiers, as demonstrated by improved frequency characteristics and increased power efficiency, with the CRLH structure reducing insertion loss and selectively filtering harmonics, and the predistortion unit offsetting intermodulation distortion.
Implementation Method 1
The input matching unit and the output matching unit may have frequency characteristics of a notch filter
Implementation Method 2
The input matching unit and the output matching unit may have a meta electromagnetic wave structure
Implementation Method 3
The predistortion unit may include a phase shifter that shifts a phase of third intermodulation distortion component of a signal input to the predistortion unit by 180°
Data Source
AI summary
An amplifier is provided. The amplifier includes an input matching unit suppressing harmonic components of an input signal; a high power amplification unit amplifying a signal suppressed by the input matching unit; and an output matching unit suppressing harmonic components of an output signal amplified by the high power amplification unit.