Vector Power Amplification for Linear RF Output at High Efficiency
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Solution Overview
Problem
Traditional power amplifiers face a tradeoff between linearity and efficiency, with linear amplifiers being inefficient and non-linear amplifiers producing spectrally distorted output signals, especially in wireless communication systems, where existing outphasing techniques suffer from insertion loss and bandwidth limitations.
Innovation Solution
The method involves decomposing time-varying complex envelope signals into substantially constant envelope signals, amplifying these, and then recombining them to minimize non-linear distortion while maximizing power efficiency, using techniques like Cartesian 4-Branch, Cartesian-Polar-Cartesian-Polar, and Direct Cartesian 2-Branch Vector Power Amplification methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional linear power amplifiers are used to achieve high linearity, then output signal quality is improved, but power efficiency deteriorates
Solution Approach 1:
The patent divides the amplification process into multiple parallel branches (e.g., 2-branch, 4-branch configurations), where each branch amplifies a constant envelope signal. This segmentation allows each amplifier to operate efficiently while the combined output achieves the desired linear signal, resolving the contradiction between linearity and power efficiency.
Solution Approach 2:
The patent transitions from single-dimensional amplitude modulation to multi-dimensional vector combining in the complex plane. By representing signals as vectors with magnitude and phase, and combining them in the complex domain, the system achieves linear amplification of time-varying envelope signals while maintaining high power efficiency through constant envelope operation in each branch.
2Loss of energy
If traditional non-linear power amplifiers are used to achieve high power efficiency, then power consumption is reduced, but output signal linearity deteriorates causing spectral distortion
Solution Approach 1:
The patent segments the amplification task across multiple parallel branches, each handling constant envelope signals that can be amplified efficiently by non-linear amplifiers. The linear combination of these amplified signals in the complex domain reconstructs the desired linear output, thereby achieving high power efficiency without spectral distortion.
Solution Approach 2:
The patent introduces complex domain combination as an intermediary process between the non-linear amplification stages and the final linear output. The vector combiner acts as a mediator that synthesizes the non-linearly amplified constant envelope signals into a linear time-varying envelope signal, eliminating spectral distortion while preserving power efficiency benefits.
3Power
If existing outphasing techniques with power combiners are used, then signal amplification is achieved, but insertion loss increases reducing power efficiency
Solution Approach 1:
The patent extracts and eliminates the power combiner component from the traditional outphasing architecture. By directly combining the amplified constant envelope signals in the complex domain without passing them through a power combiner, the system removes the source of insertion loss while maintaining signal amplification capability.
4Power
If existing outphasing techniques with combining elements are used, then signal combination is achieved, but bandwidth is limited
Solution Approach 1:
The patent replaces the mechanical/physical power combining elements (such as hybrid couplers and isolators) with a mathematical complex domain combination approach. This substitution eliminates the bandwidth limitations inherent in physical combining elements while maintaining the signal combination function, thereby extending the operational bandwidth of the amplifier system.
Data Source
AI summary
Methods and systems for vector combining power amplification are disclosed herein. In one embodiment, a plurality of signals are individually amplified, then summed to form a desired time-varying complex envelope signal. Phase and/or frequency characteristics of one or more of the signals are controlled to provide the desired phase, frequency, and/or amplitude characteristics of the desired time-varying complex envelope signal. In another embodiment, a time-varying complex envelope signal is decomposed into a plurality of constant envelope constituent signals. The constituent signals are amplified equally or substantially equally, and then summed to construct an amplified version of the original time-varying envelope signal. Embodiments also perform frequency up-conversion.