RF Power Semiconductor Distortion Compensation Using Dual Filter Networks
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Solution Overview
Problem
Existing power semiconductor devices, particularly GaN-based devices, suffer from significant narrowband distortion effects due to charge-trapping phenomena, which lead to inefficiencies and limitations in high-frequency applications.
Innovation Solution
The implementation of a radio frequency power semiconductor device that employs a first non-linear filter network comprising orthogonal IIR filters, including low pass and all-pass filters, to correct narrowband distortion, and a second non-linear filter network using FIR filters to address broadband distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If GaN-based power semiconductor devices are used for high-frequency applications, then power and frequency performance are improved, but narrowband distortion due to charge-trapping effects increases
Solution Approach 1:
The patent applies preliminary anti-action by using digital predistortion to pre-compensate for charge-trapping effects before the signal reaches the power amplifier. The system models the narrowband distortion characteristics and applies inverse distortion in advance, canceling out the harmful effects before they manifest in the output signal.
Solution Approach 2:
The patent changes parameters by dynamically adjusting predistortion coefficients based on operating conditions. The system adapts to varying charge-trapping effects by modifying filter parameters and distortion compensation levels, allowing optimal performance across different power and frequency operating points.
2Manufacturing precision
If digital predistortion is applied to correct narrowband distortion, then gain linearity is improved, but device complexity increases
Solution Approach 1:
The patent segments the distortion correction function into separate IIR filter stages, each handling specific aspects of narrowband distortion. This modular approach allows independent optimization of each filter stage and simplifies the overall design by dividing the complex predistortion function into manageable components.
Solution Approach 2:
The patent replaces complex analog compensation circuits with digital signal processing implementations. By using digital IIR filters and software-based predistortion algorithms, the system achieves precise gain linearity control without requiring complex physical circuitry, thereby reducing hardware complexity while maintaining high precision.
3Reliability
If IIR filters are used to correct narrowband distortion, then distortion correction effectiveness is improved, but computational requirements and processing time increase
Solution Approach 1:
The patent implements periodic action by using recursive IIR filter structures that efficiently process signals through repeated application of fixed coefficient equations. This periodic computational approach allows rapid processing of each signal sample using standardized mathematical operations, reducing overall processing time while maintaining correction effectiveness.
Data Source
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AI summary
Some embodiments herein describe a radio frequency power semiconductor device that include a first non-linear filter network for compensating for lower frequency noise of a power amplifier. The first non-linear filter network can include a plurality of infinite impulse response filters and corresponding corrective elements to correct for a non-linear portion of the power amplifier. The radio frequency power semiconductor device can further include a second non-linear filter network for compensating for broadband distortion. The second non-linear filter network can be connected in parallel to the first non-linear filter network. The broadband distortion can include digital predistortion and the narrowband distortion can include charge trapping effects. The first non-linear filter network can comprise Laguerre filters. The second non-linear filter network can comprise general memory polynomial filters.