Output Matching Trap Circuit for Wideband Harmonic Suppression
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Solution Overview
Problem
Conventional power amplifiers for radio communication systems fail to effectively suppress second and third harmonics over a wide frequency band, leading to inefficient operation and radiation issues.
Innovation Solution
A power amplifier design incorporating multiple trap circuits with series resonant circuits, including capacitors and inductors, is implemented in the output matching circuit to short-circuit impedance at frequencies higher than the transmission frequency band, ensuring efficient suppression of second and third harmonics across a wide frequency range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single trap circuit is used in conventional power amplifiers, then the circuit structure is simple, but the suppression of second and third harmonics is ineffective over a wide frequency band
Solution Approach 1:
The patent divides the single trap circuit into multiple trap circuits (first trap circuit and second trap circuit), each targeting different harmonic frequencies. The first trap circuit suppresses the second harmonic while the second trap circuit suppresses the third harmonic, enabling effective wideband harmonic suppression across the frequency band.
2Object-generated harmful factors
If multiple trap circuits are added to suppress harmonics over wide frequency band, then harmonic suppression improves, but device complexity increases
Solution Approach 1:
Each trap circuit is designed with specific local characteristics tailored to its target harmonic frequency. The first trap circuit has impedance characteristics optimized for second harmonic suppression, while the second trap circuit has characteristics optimized for third harmonic suppression. This localized optimization allows effective harmonic suppression without requiring a completely redesigned complex circuit.
3Manufacturing precision
If trap circuits are designed for specific frequencies, then harmonic suppression at those frequencies is effective, but performance degrades across wide frequency band
Solution Approach 1:
The multiple trap circuits are designed to work together as a universal solution for wideband harmonic suppression. Each trap circuit maintains its specialized function for a specific harmonic frequency, while the combination provides universal coverage across the entire operating frequency band, achieving both precision suppression and wideband adaptability.
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 achieves high efficiency and effective suppression of second and third harmonics over a wide frequency band, enhancing the power amplifier's performance and operational efficiency.
Implementation Method 1
A power amplifier design incorporating multiple trap circuits with series resonant circuits, including capacitors and inductors, is implemented in the output matching circuit to short-circuit impedance at frequencies higher than the transmission frequency band
Data Source
AI summary
Two trap circuits different in frequencies at which short-circuit is established are provided in an output matching circuit. Out of the two trap circuits, the trap circuit higher in frequency at which short-circuit is established is arranged closer to a power amplification element. Thus, a frequency band higher than a frequency twice as high as a central frequency of a transmission frequency band is trapped, impedance of the output matching circuit with respect to the frequency in a frequency band twice as high as the transmission frequency band on the side of an output end of the power amplification element is kept in a state close to short-circuit, and the trap circuit lower in frequency at which short-circuit is established traps the frequency band lower than the frequency twice as high as the central frequency of the transmission frequency band.