Multi-Mode Linear Power Amplifier Without Wilkinson Combiner Loss
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Solution Overview
Problem
Existing power amplifier systems face challenges in achieving high power added efficiency (PAE) across a range of power levels without compromising linearity and performance, particularly in dual-mode power amplifiers where improving PAE at low power levels often comes at the expense of linearity at higher power levels.
Innovation Solution
The implementation of a multi-mode high efficiency linear power amplifier with multiple amplification paths, where each path includes independent output impedance modification and phase shift elements, allowing for selective impedance and phase control, enabling improved impedance matching and phase balance without the need for a Wilkinson power combiner, which reduces signal loss and component count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If multiple amplification paths are implemented to provide varying power output levels, then power added efficiency at low power levels is improved, but linearity at higher power levels deteriorates
Solution Approach 1:
The power amplifier is divided into multiple independent amplification paths (first and second paths), each capable of operating independently to provide different power output levels. This segmentation allows the system to select appropriate paths based on required power level, improving efficiency at low power while maintaining linearity at high power through coordinated operation of both paths
Solution Approach 2:
The system dynamically switches between different amplification paths and combinations thereof based on the required power output level. The first amplification path is enabled for low power levels, while both first and second paths are enabled for high power levels, allowing the system to adapt its configuration to maintain optimal performance across different operating conditions
2Loss of energy
If independent output impedance modification and phase shift elements are implemented for each amplification path, then power added efficiency and linearity are improved, but device complexity increases
Solution Approach 1:
Each amplification path is equipped with its own dedicated output impedance modification element and phase shift element, allowing independent optimization of impedance matching and phase balance for each path. This local quality approach enables each path to operate at its optimal performance point, improving overall power added efficiency and linearity
Solution Approach 2:
The output combining circuit serves multiple functions: it combines signals from different amplification paths, provides impedance transformation, and maintains phase balance. This multi-functional design reduces the need for separate components and eliminates the need for a Wilkinson power combiner, thereby reducing overall device complexity despite the addition of path-specific control elements
Data Source
AI summary
A power amplifier includes a plurality of amplification paths in which at least one amplification path is selectively enabled and disabled, wherein each amplification path includes an output impedance modification element and an output phase shift element that is operable independently from the output impedance modification element, and wherein the output impedance modification element in each amplification path provides selective impedance for each amplification path.