Multi-Band Output Matching Circuit for Harmonic Suppression
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Solution Overview
Problem
Conventional power amplifier output matching circuits fail to provide sufficient power efficiency and harmonic suppression across a wide range of operating conditions, including back-off power levels, in power amplifier systems employing supply voltage modulation.
Innovation Solution
The proposed power amplifier system incorporates an output matching circuit with multiple matching circuits and harmonic resonant circuits, including second-order and third-order harmonic resonant circuits, to suppress harmonics and match output impedance across different frequency bands, thereby enhancing power efficiency and harmonic rejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional output matching circuit is used, then the circuit structure is simple, but power efficiency is insufficient and harmonic suppression is inadequate across wide operating conditions
Solution Approach 1:
The output matching circuit is divided into multiple independent matching circuits (first matching circuit, second matching circuit, third matching circuit) each optimized for specific operating conditions. Each matching circuit includes specific harmonic resonant circuits (second-order, third-order) tailored to particular power levels and frequency bands, allowing optimal performance across wide operating ranges while maintaining manageable complexity through modular design
Solution Approach 2:
The system dynamically switches between different matching circuits based on operating conditions (power level, frequency band). The power amplifier selectively activates appropriate matching circuits and harmonic resonant circuits according to real-time operating parameters, enabling adaptive optimization of power efficiency and harmonic suppression without requiring a single complex static circuit
2Object-generated harmful factors
If a single matching circuit is used, then the device complexity is low, but harmonic suppression is insufficient across different frequency bands
Solution Approach 1:
Each matching circuit is designed with specific local characteristics optimized for particular frequency bands and power levels. The first matching circuit includes second-order and third-order harmonic resonant circuits for low-band optimization, the second matching circuit includes third-order harmonic resonant circuits for high-band optimization, and the third matching circuit provides additional harmonic suppression. This localized optimization ensures superior harmonic suppression in each specific operating condition
Solution Approach 2:
The output matching circuit system provides universal harmonic suppression across multiple frequency bands and power levels by integrating multiple matching circuits that can be selectively activated. The system universally handles both low-band and high-band operations, peak saturation and back-off power levels, through a unified multi-circuit architecture that adapts to diverse operating conditions
3Loss of energy
If conventional matching circuits are used, then the circuit design is simple, but power efficiency at back-off power levels is insufficient
Solution Approach 1:
The power amplifier system dynamically selects and switches between different matching circuits based on real-time power level detection. At back-off power levels, the system activates specific matching circuits (first, second, or third matching circuit) that are optimized for efficient operation at reduced power levels, maintaining high power efficiency across the entire operating range from peak saturation to back-off conditions
Solution Approach 2:
The system changes operating parameters by switching between different matching circuit configurations depending on power level. Each matching circuit is designed with specific impedance transformations and harmonic resonant characteristics optimized for particular power ranges. This parameter adaptation through circuit switching enables optimal power efficiency at both peak and back-off power levels
4Object-generated harmful factors
If multiple matching circuits are used for different bands, then harmonic suppression is improved, but the device complexity increases
Solution Approach 1:
The harmonic suppression function is segmented into multiple specialized matching circuits, each handling specific frequency bands and harmonic orders. The first matching circuit handles low-band harmonics with second-order and third-order resonant circuits, the second matching circuit handles high-band harmonics with third-order resonant circuits, and the third matching circuit provides additional suppression. This segmentation achieves superior harmonic rejection while keeping each individual circuit module relatively simple and manageable
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The described solution achieves high efficiency at peak saturation and back-off power levels, while providing robust harmonic suppression and maintaining stability under varying voltage standing wave ratio (VSWR) conditions.
Implementation Method 1
a second-order harmonic resonant circuit that is configured to suppress second-order frequency signal components of the amplified radio frequency signal
Implementation Method 2
a first third-order harmonic resonant circuit that is configured to suppress third-order frequency signal components of the amplified radio frequency signal
Implementation Method 3
the second-order harmonic resonant circuit includes a capacitor and an inductor connected in parallel
Implementation Method 4
each of the first and second third-order harmonic resonant circuits includes a capacitor and an inductor connected in series to ground
Data Source
AI summary
Apparatus and methods for power amplifier output matching is disclosed. In one aspect, there is provided an output matching circuit including an input configured to receive an amplified radio frequency signal from a power amplifier, a first output, and a second output. The output matching circuit further includes a first matching circuit electrically connected between the input of the output matching circuit and the first output, the first matching circuit configured to suppress harmonics of a fundamental frequency of the amplified radio frequency signal when the amplified radio frequency signal is within a first band. The output matching circuit further includes a second matching circuit electrically connected between the input of the output matching circuit and the second output, the second matching circuit configured to suppress harmonics of the fundamental frequency of the amplified radio frequency signal when the amplified radio frequency signal is within a second band different from the first band.