Complementary HEMT Power Amplifier Linearization for Harmonic Reduction
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Solution Overview
Problem
Power amplifiers in electronic devices often suffer from non-linearity due to higher-order harmonics, which adversely impact their performance, particularly in wireless devices where signal amplification requires constant gain across varying input signal magnitudes.
Innovation Solution
Incorporating a complementary power switch, such as a complementary high-electron-mobility transistor (HEMT), which is selected and operated to mitigate the effects of higher-order harmonics in the primary power switch, thereby improving the overall linearity of the power amplifier by balancing and reducing these harmonics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single power switch is used for signal amplification, then the device complexity is low, but the linearity is poor due to higher-order harmonics
Solution Approach 1:
The power amplifier is segmented into two complementary power switches (first and second HEMTs) with different operating characteristics. Each switch handles different portions of the signal cycle, with the first HEMT operating in saturation region and the second HEMT operating in triode region, thereby reducing higher-order harmonics and improving linearity while maintaining manageable device complexity through functional division
Solution Approach 2:
The patent employs a composite structure using two different types of HEMT devices with complementary characteristics. The first HEMT (depletion-type) and second HEMT (enhancement-type) are combined to create a push-pull configuration that leverages their different transfer characteristics to cancel out nonlinear distortion components, effectively improving linearity without excessive complexity increase
2Power
If power amplifier amplifies input signal, then the output signal power increases, but higher-order harmonics increase causing non-linearity
Solution Approach 1:
The patent converts the harmful effect of higher-order harmonics generated during signal amplification into a beneficial cancellation effect. By using complementary HEMTs with opposite polarity characteristics, the nonlinear distortion components generated by each device cancel each other out, allowing high power amplification to be achieved while maintaining linearity and reducing harmonic distortion
Solution Approach 2:
Two different types of HEMT devices (depletion-type and enhancement-type) are combined in a push-pull configuration. Each device type generates higher-order harmonics with opposite polarity, and when combined, these harmonics cancel each other out, enabling high power output with improved linearity and reduced non-linear distortion
Data Source
AI summary
According to at least one example of the disclosure, a power amplifier is provided comprising a first power switch of a first type being configured to receive an input signal and provide an amplified output signal to an output connection configured to be coupled to a load, and a second power switch of a second type different than the first type, the second power switch being configured to improve a linearity of the power amplifier and being coupled to the output connection.