RF Power Amplifier with IM2 Injection for IM3 Distortion Mitigation
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Solution Overview
Problem
Designing a satisfactory radio-frequency power amplifier for electronic devices is challenging due to non-linear behavior, which results in intermodulation distortion, particularly third-order intermodulation distortion, affecting signal fidelity and amplifier efficiency.
Innovation Solution
Incorporating a second-order intermodulation generation circuit that injects second-order intermodulation signals into the radio-frequency power amplifier to mix with input signals, canceling out third-order intermodulation products and improving the amplifier's linearity without degrading efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a power amplifier is designed to amplify radio-frequency signals, then the transmission power is increased, but third-order intermodulation distortion occurs due to non-linear behavior
Solution Approach 1:
The patent applies preliminary anti-action by generating second-order intermodulation signals in advance and injecting them into the amplifier input. These pre-generated signals interact with the non-linear amplifier to produce third-order intermodulation products that cancel out the harmful distortion components, thereby preventing the net accumulation of intermodulation distortion while maintaining high transmission power
2Manufacturing precision
If linearization techniques are applied to reduce intermodulation distortion, then signal fidelity is improved, but amplifier efficiency is degraded
Solution Approach 1:
The patent changes the signal parameters by injecting second-order intermodulation signals with specific amplitude and phase characteristics. This parameter modification allows the system to achieve linearization and reduce intermodulation distortion without requiring traditional efficiency-degrading techniques such as feedback linearization or predistortion that consume additional power
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 reduces third-order intermodulation distortion, enhancing the fidelity of transmitted signals while maintaining the overall efficiency of the power amplifier.
Implementation Method 1
A power amplifier may exhibit third order non-linearity resulting in third order intermodulation products that can distort the radio-frequency signals during amplification
Implementation Method 2
an input transformer configured to receive a radio-frequency signal and coupled to the gate terminals of the first and second input transistors
Data Source
AI summary
An electronic device may include wireless circuitry with a processor, a transceiver, an antenna, and a front-end module coupled between the transceiver and the antenna. The front-end module may include one or more power amplifiers for amplifying a signal for transmission through the antenna. Radio-frequency power amplifier circuitry may include an amplifier, an input transformer for coupling radio-frequency input signals to the amplifier, an active inductor load coupled to the input transformer, and a second order intermodulation generation circuit configured to generate and inject a second order intermodulation product into the input transformer. The injected second order intermodulation product can be used to cancel out unwanted third order intermodulation products generated by the amplifier, which reduces intermodulation distortion experienced by the amplifier circuitry.