Output Matching Circuit With Harmonic Shorting and Impedance Conversion
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Solution Overview
Problem
Existing power amplifier circuits face significant losses in the frequency band intended to be passed due to insufficient attenuation in the harmonic wave termination circuit, especially under varying impedance conditions.
Innovation Solution
The proposed output matching circuit includes a converter for impedance conversion by magnetic coupling and a first filter circuit that creates a short circuit in a frequency band different from the predetermined transmission frequency band, thereby suppressing losses and ensuring adequate attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a harmonic wave termination circuit is used to achieve class-F or inverse class-F power amplifier circuit by switching the frequency with a capacitor and switch, then frequency switching capability is improved, but losses in the frequency band desired to be passed increase due to insufficient attenuation under varying impedance conditions
Solution Approach 1:
The output matching circuit is divided into three functional segments: a first filter circuit for harmonic termination, a converter for impedance conversion, and a second filter circuit for passband filtering. This segmentation allows each segment to optimize its function independently, reducing overall losses while maintaining frequency switching capability.
Solution Approach 2:
The converter acts as an intermediary component between the first filter circuit and the second filter circuit. It performs impedance conversion to match the impedance conditions required by each filter circuit, enabling both to function optimally without direct interference, thus reducing losses in the passband.
2Reliability
If a harmonic wave termination circuit is used to ensure attenuation at harmonic frequencies, then attenuation at unwanted frequencies is improved, but losses in the frequency band desired to be passed increase due to impedance mismatch conditions
Solution Approach 1:
Different parts of the circuit are designed with different impedance characteristics optimized for their specific function: the first filter circuit has impedance optimized for harmonic termination, the converter provides impedance transformation, and the second filter circuit has impedance optimized for passband transmission. This local optimization ensures high attenuation at harmonics while minimizing losses in the passband.
Solution Approach 2:
The converter dynamically adjusts impedance parameters between the first and second filter circuits. By changing the impedance parameter to match the requirements of each stage, the circuit achieves reliable attenuation at harmonic frequencies while preventing impedance mismatch losses in the passband.
3Reliability
If impedance conversion is performed to match conditions for harmonic termination, then attenuation performance is improved, but device complexity increases due to additional converter component
Solution Approach 1:
The converter is designed to perform multiple functions: impedance conversion between stages, harmonic suppression, and passband preservation. By making the converter multi-functional, the overall device complexity is minimized while still achieving the required attenuation performance and frequency switching capability.
Solution Approach 2:
The converter combines impedance conversion functionality with harmonic termination capabilities in a single component. This merging of functions reduces the total number of discrete components needed, thereby reducing device complexity while maintaining reliable attenuation performance.
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
This configuration effectively reduces losses in the pass band while ensuring sufficient attenuation at the desired frequency, enhancing the efficiency of the power amplifier circuit.
Implementation Method 1
a converter electrically connected to an output end of a power amplifier element to convert an impedance of the output end to an impedance higher than the impedance of the output end by magnetic coupling
Implementation Method 2
a first filter circuit electrically connected between the output end of the power amplifier element and the converter to make a short circuit in a frequency band different from a predetermined transmission frequency band
Data Source
AI summary
An output matching circuit includes: a converter electrically connected to an output end of a power amplifier element to convert an impedance of the output end to an impedance higher than the impedance of the output end by magnetic coupling; and a first filter circuit electrically connected between the output end of the power amplifier element and the converter to make a short circuit in a frequency band different from a predetermined transmission frequency band.