Bridge Predistortion Linearizer With Per-Arm Equalization
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Solution Overview
Problem
Current power amplifier linearizers are limited in their ability to compensate for nonlinear behavior across a wide frequency bandwidth, as they can only adapt to a portion of the operating frequency, leading to inadequate linearization for remaining frequencies, especially in the double-digit GHz range where parasitic effects complicate frequency response control.
Innovation Solution
Incorporating an equalizer stage in both the linear and nonlinear bridge branches to introduce precise amplitude and phase responses, allowing for adjustment of the frequency response and compensating for parasitic effects such as stray capacitances and bond inductances, enabling broadband linearization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a linearizer bridge is used without equalizer stages in each bridge arm, then the device complexity is reduced, but the frequency response control becomes difficult and manufacturing precision deteriorates due to parasitic effects
Solution Approach 1:
The linearizer bridge is segmented into multiple independent bridge arms (first and second bridge arms), with each arm containing its own equalizer stage. This segmentation allows independent adjustment of frequency response for each arm, enabling precise compensation of parasitic effects while maintaining overall system manageability through modular structure.
Solution Approach 2:
Each bridge arm is equipped with dedicated equalizer stages that provide local frequency response adjustment. The equalizer stages in different bridge arms can have different characteristics, allowing localized compensation for parasitic effects specific to each arm, thereby achieving high manufacturing precision without requiring complete redesign of the entire bridge structure.
2Manufacturing precision
If equalizer stages are added to each bridge arm, then the frequency response control and manufacturing precision are improved, but the device complexity increases
Solution Approach 1:
The equalizer stages are designed with universal functionality to perform multiple tasks: frequency response adjustment, parasitic effect compensation, and amplitude/phase characteristic control. By using the same equalizer stage design across different bridge arms, the patent achieves high manufacturing precision without proportionally increasing device complexity, as the same modular component serves multiple purposes.
3Device complexity
If the linearizer is designed for a limited frequency range, then the device complexity is reduced, but the adaptability to different frequency bandwidths deteriorates
Solution Approach 1:
The equalizer stages incorporate variable adjustment mechanisms that allow dynamic adaptation to different frequency ranges. The equalizer characteristics can be modified to match specific amplifier frequency responses, enabling the linearizer bridge to adapt to broadband amplifiers across different frequency bands without requiring complete redesign, thus achieving high versatility with manageable complexity.
Data Source
AI summary
Disclosed is a predistortion linearizer for power amplifiers using a bridge topology, which has the advantages that an equalizer stage is disposed in each of the linear and nonlinear branches. This equalizer stage is used to adjust the frequency response of the complex expansion of the bridge. The equalizers introduce variable transmission functions in the linear and nonlinear bridge branches, so that the linearizer compensates for the individual nonlinear frequency response of a power amplifier, which varies within a manufacturing lot.