Power Amplifier Matching Circuit for Second-Harmonic Impedance Control
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Solution Overview
Problem
Existing matching circuits in power amplifier circuits fail to control second-harmonic impedance, leading to reduced efficiency.
Innovation Solution
A matching circuit design that includes specific configurations of inductors, capacitors, and resonant circuits to control harmonic impedances, particularly setting the second-harmonic load impedance to zero or infinity, thereby improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional matching circuit is used, then the circuit structure is simple, but the second-harmonic impedance cannot be controlled and efficiency is reduced
Solution Approach 1:
The matching circuit is divided into multiple functional segments: a first matching network for fundamental frequency impedance matching, and a second matching network (series resonant circuit) specifically for second-harmonic impedance control. This segmentation allows independent optimization of fundamental frequency efficiency and harmonic control, resolving the contradiction between maintaining simple structure and achieving improved efficiency through harmonic management.
Solution Approach 2:
A series resonant circuit is introduced as an intermediary component between the power amplifier output and the load. This resonant circuit acts as a mediator that selectively controls second-harmonic impedance while allowing the fundamental frequency to pass through with minimal interference, thereby improving efficiency without significantly complicating the overall circuit structure.
2Loss of energy
If the matching circuit controls second-harmonic impedance, then efficiency is improved, but the circuit complexity increases
Solution Approach 1:
The circuit merges two matching networks into a single integrated structure where the first matching network handles fundamental frequency impedance transformation and the second matching network (series resonant circuit) handles second-harmonic control. By combining these functions in one unified circuit architecture rather than separate stages, the patent achieves harmonic control with minimal additional complexity.
Solution Approach 2:
The matching circuit is designed with multi-functionality: the same circuit structure simultaneously performs fundamental frequency impedance matching and second-harmonic impedance control. This universal design allows a single circuit to achieve multiple objectives (efficiency improvement through both fundamental matching and harmonic control) without requiring separate dedicated circuits for each function, thereby limiting the increase in overall complexity.
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 proposed matching circuit enhances the efficiency of power amplifier circuits by allowing class-F operation and increasing bandwidth, maintaining optimal impedance across various frequency bands.
Implementation Method 1
a first series resonant circuit connected in parallel to the second inductor
Implementation Method 2
a second series resonant circuit connected in parallel to the first capacitor
Data Source
AI summary
A matching circuit includes an input terminal configured to receive an amplified signal from a power amplifier, an output terminal, a first inductor having a first end connected to the input terminal, and a second end connected to the output terminal, a first capacitor connected in parallel to the first inductor, a second inductor having a first end connected to the input terminal, and a second end connected to ground, and a first series resonant circuit connected in parallel to the second inductor.