Doherty Input Power Splitter Tuning for Gain Linearity
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Solution Overview
Problem
Conventional Doherty amplifiers face performance issues due to semiconductor process abnormalities, such as variations in gate oxide thickness and doping levels, leading to poor gain linearity and mismatched components, which affect the amplifiers' performance in mass production, especially when dealing with wide operational frequency bands.
Innovation Solution
An adjustable input power splitter with a resistive element is introduced, allowing for dynamic tuning of gain linearity by adjusting the power division ratio between the main and peak amplifier stages based on their respective gains, frequency, and operational power levels, ensuring optimal power split and phase alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional Doherty amplifiers are used with fixed power splitter, then manufacturing simplicity is maintained, but gain linearity and performance are degraded due to semiconductor process variations
Solution Approach 1:
The patent implements a dynamic power splitter that can adjust the power division ratio between main and peak amplifier stages based on operating conditions. This is achieved through variable components (such as switches and controllable impedances) that allow the power split to be optimized for different frequency bands and power levels, thereby compensating for process variations and improving gain linearity while maintaining manageable device complexity through controlled adaptability.
Solution Approach 2:
The patent changes the electrical parameters of the power splitter by introducing controllable impedance elements that can be adjusted during operation. By varying the power division ratio parameter dynamically, the system compensates for manufacturing tolerances and process abnormalities, achieving better gain linearity without permanently increasing structural complexity.
2Adaptability or versatility
If fixed power division ratio is used, then device simplicity is maintained, but performance degrades across wide operational frequency bands due to mismatched components
Solution Approach 1:
The patent employs a dynamic power splitter configuration that can reconfigure the power division ratio adaptively across different frequency bands. Using controllable switches and variable impedance elements, the system optimizes the power split for each operating band, enabling wideband operation with maintained performance without requiring completely separate fixed circuits for each band.
Solution Approach 2:
The patent designs a universal power splitter structure that can serve multiple frequency bands and operating conditions through a single reconfigurable circuit. By incorporating controllable elements that allow dynamic adjustment, the same physical structure performs multiple functions across different bands, reducing the need for separate dedicated circuits and managing overall device complexity.
3Productivity
If semiconductor process abnormalities occur, then mass production efficiency is maintained, but component matching and gain linearity are degraded
Solution Approach 1:
The patent implements a feedback mechanism where the actual performance of the amplifier stages is monitored and used to adjust the power division ratio dynamically. This feedback loop compensates for component mismatches caused by process variations, ensuring consistent gain linearity across mass-produced devices without requiring tighter manufacturing tolerances that would reduce production efficiency.
Solution Approach 2:
The patent compensates for component matching errors by dynamically adjusting the power division ratio parameter based on measured or predetermined performance characteristics. This allows mass-produced devices with varying component parameters to be tuned to consistent performance levels, maintaining both productivity and manufacturing precision.
Data Source
AI summary
Embodiments of a Doherty amplifier device are provided, including a first amplifier stage having a first gain; a second amplifier stage having a second gain that is less than the first gain; and an input power splitter coupled to inputs of the first and second amplifier stages, wherein the input power splitter includes either an inductive element, a capacitive element, or both coupled between the inputs of the first and second amplifier stages, and a resistive element coupled to the input of the second amplifier stage, the input power splitter respectively delivers first and second power levels to inputs of the first and second amplifier stages, and the resistive element is configured to tune gain linearity of the Doherty amplifier device by increasing the second power level to be greater than the first power level, based on a ratio of the second gain to the first gain.