Transformer Output Matching Circuit for Harmonic Loss Suppression
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Solution Overview
Problem
Existing power amplifier modules suffer from increased loss in the output matching circuit due to harmonic termination circuits being placed between the output stage transistor and the output matching circuit, hindering efficiency improvement.
Innovation Solution
An output matching circuit design that includes a transformer to convert impedance, and filter circuits to attenuate specific harmonic frequencies, with filter circuits connected to ground at strategic nodes to secure attenuation where needed and suppress loss where unnecessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If harmonic termination circuits are provided between the output stage transistor and the output matching circuit, then harmonic components are attenuated, but loss in the output matching circuit increases
Solution Approach 1:
The output matching circuit is divided into multiple sections: a first output matching circuit connected to the output stage transistor, a second output matching circuit connected to the load, and harmonic termination circuits positioned between these two matching circuits. This segmentation allows each circuit section to perform its specific function optimally without interfering with others, reducing overall loss while maintaining harmonic attenuation.
Solution Approach 2:
The first output matching circuit acts as an intermediary between the output stage transistor and the harmonic termination circuits. It transforms the impedance and signals before they reach the harmonic termination circuits, allowing for more effective harmonic attenuation with reduced impact on the main signal path and overall circuit loss.
2Object-generated harmful factors
If filter circuits are added to attenuate harmonic frequencies, then attenuation performance improves, but device complexity increases
Solution Approach 1:
The output matching circuits are designed to serve multiple functions: impedance transformation, signal transmission, and harmonic attenuation. By making the matching circuits multi-functional, additional filter circuits are not needed, thereby maintaining circuit simplicity while achieving effective harmonic attenuation through proper impedance transformation and signal routing.
Solution Approach 2:
The harmonic termination function is merged into the overall output matching structure rather than being implemented as separate, standalone filter circuits. The first and second output matching circuits work together with the harmonic termination circuits to achieve both impedance matching and harmonic attenuation in a unified design, reducing overall device 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 design effectively secures attenuation in desired frequency bands while minimizing loss in undesired bands, improving efficiency and reducing interference between filter circuits.
Implementation Method 1
a transformer (121) having one end electrically connected to a collector of the power amplifier element (110) and the other end electrically connected to an output terminal 120d, and converting an impedance of the output terminal 120d to an impedance higher than an impedance of the collector
Data Source
AI summary
An output matching circuit includes a transformer having one end electrically connected to an output terminal of a power amplifier element that amplifies an input signal and another end electrically connected to a terminal connected to a load, and converting an impedance of the terminal connected to the load to an impedance higher than an impedance of the output terminal, a first filter circuit that attenuates a signal within a first frequency band higher than a transmission frequency band of the input signal, and a second filter circuit that attenuates a signal within a second frequency band higher than the first frequency band.