Dual-Path Amplifier Phase Compensation for Harmonic Cancellation
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Solution Overview
Problem
Conventional dual-path power amplifiers for wireless communication systems suffer from harmonic distortion due to non-ideal phase offsets at harmonic frequencies, leading to undesirable signal interference and loss at frequencies other than the fundamental frequency.
Innovation Solution
The dual-path power amplifier design features transmission lines with distinct physical and electrical characteristics to compensate for the phase offset deficit of the power combiner at the second harmonic frequency, ensuring a cumulative phase offset of approximately 180 degrees, thereby reducing harmonic distortion while maintaining optimal performance at the fundamental frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transmission lines are designed with identical electrical characteristics at the fundamental frequency, then optimal signal combining is achieved at the fundamental frequency, but harmonic distortion occurs at the second harmonic frequency due to non-ideal phase offsets
Solution Approach 1:
The patent applies asymmetry by designing the first and second transmission lines with different electrical characteristics. Specifically, the transmission lines have different characteristic impedances or different electrical lengths, creating asymmetric phase shifts at the second harmonic frequency. This asymmetric design enables the phase offset between the two paths to reach approximately 180 degrees at the second harmonic, achieving harmonic cancellation while maintaining symmetric performance at the fundamental frequency through careful impedance matching and length optimization.
2Object-generated harmful factors
If transmission lines have different electrical characteristics to cancel harmonics, then harmonic distortion is reduced, but signal combining efficiency at the fundamental frequency deteriorates
Solution Approach 1:
The patent applies local quality by making each transmission line have specific electrical characteristics optimized for its particular function. The first transmission line is designed with specific impedance and length to provide a certain phase shift at the second harmonic, while the second transmission line has different characteristics to provide a complementary phase shift. At the same time, both lines are designed to maintain proper impedance matching at the fundamental frequency, ensuring efficient signal combining only at the desired operating frequency while achieving harmonic cancellation.
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
This design effectively minimizes harmonic distortion in the output signal by achieving significant cancellation at the second harmonic frequency without impacting the phase match at the fundamental frequency, resulting in improved signal quality and efficiency.
Implementation Method 1
the electrical characteristics of each transmission line result in some degree of attenuation and some amount of phase shift as the corresponding amplified component traverses the transmission line towards the power combiner
Data Source
AI summary
An embodiment of a dual-path amplifier includes a power splitter connected to first and second power amplifiers respectively connected to first and second transmission lines connected to a power combiner having a phase-offset deficit at the second harmonic frequency 2f0, where the first and second transmission lines are designed to provide a complementary phase offset at 2f0 substantially equal to the phase-offset deficit such that the two amplified signals will be combined at the power converter with a total phase offset at 2f0 of about 180 degrees in order to reduce harmonic distortion in the amplified output signal, without substantially diminishing the output power at the fundamental frequency f0. In certain PCB-based implementations, the transmission lines include metal traces and lumped elements providing different impedance transformations that achieve the complementary phase offset, where the metal traces may have significantly different physical and electrical characteristics.