Vector Combining Power Amplifier for Linear and Efficient RF Output

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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, particularly in wireless communication systems, and existing outphasing techniques suffer from insertion loss and bandwidth limitations.

Innovation Solution

The method of vector combining power amplification, where a time-varying complex envelope signal is decomposed into substantially constant envelope signals, amplified individually, and then recombined to minimize non-linear distortion while maximizing efficiency, allowing for efficient amplification of complex signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional linear power amplifiers are used to maintain signal linearity, then output signal quality is improved, but power efficiency deteriorates

Engineering Contradiction:

Improvesignal linearityVSAvoidpower efficiency

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The complex modulated signal is segmented into multiple constant envelope signals through signal decomposition. Each constant envelope signal is then amplified by a separate power amplifier operating in saturation mode, and the amplified signals are recombined to reconstruct the original complex signal with improved power efficiency while maintaining linearity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a composite amplification architecture combining multiple parallel power amplifier channels. Each channel processes a constant envelope signal component, and the composite output achieves both high efficiency (from saturated operation) and high linearity (from coherent recombination of components)

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If traditional non-linear power amplifiers are used to improve power efficiency, then power efficiency is improved, but output signal linearity deteriorates

Engineering Contradiction:

Improvepower efficiencyVSAvoidsignal linearity

Core Design Contradiction:

Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The complex signal is decomposed into constant envelope components that can be processed by non-linear amplifiers. By segmenting the signal in this way, each component can be amplified to saturation (high efficiency) without introducing harmful non-linear distortion to the overall signal when recombined

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention converts the harmful non-linear distortion that would normally result from saturated amplifier operation into a beneficial feature. By designing the system so that constant envelope signals are amplified to saturation and then coherently recombined, the apparent non-linearity of each amplifier channel becomes irrelevant, while the overall system achieves both high efficiency and high linearity

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of operation

If power combiners are used to combine constant envelope constituent signals, then signal combining is achieved, but insertion loss increases and bandwidth is limited

Engineering Contradiction:

Improvesignal combining capabilityVSAvoidinsertion loss

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The invention extracts the combining function from traditional passive power combiners and implements it through active signal processing. The constant envelope signals are combined through coherent addition at the output of the amplifiers, eliminating the need for separate combining hardware and its associated losses and bandwidth limitations

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS8026764B2Generation and amplification of substantially constant envelope signals, including switching an output among a plurality of nodes

Publication Date: 2011.09.27 PARKERVISION INC

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.