Differential PA Matching Network Using LC Harmonic Traps
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Solution Overview
Problem
Power amplifier circuits in mobile communication devices, especially those using differential amplifiers and transformers, tend to produce harmonic distortion due to nonlinear gain and phase characteristics, which is not effectively suppressed by existing configurations.
Innovation Solution
A matching network is introduced that includes a transformer and LC series resonant circuits connected in parallel with the transformer windings, where the resonant frequencies of these circuits are aligned with harmonic frequencies to suppress harmonic output, comprising a capacitive and inductive element series connected in parallel with the transformer windings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a differential amplifier and transformer are used for output matching, then wide frequency band matching is achieved, but harmonic output is not suppressed
Solution Approach 1:
The matching network is segmented into multiple functional components: the transformer for wideband matching and separate LC series resonant circuits for harmonic suppression. This segmentation allows each component to perform its specialized function independently, resolving the contradiction between wideband matching and harmonic suppression.
Solution Approach 2:
LC series resonant circuits are introduced as intermediary elements between the transformer and the output. These resonant circuits act as mediators that selectively suppress harmonic frequencies while allowing the main signal band to pass through, thus resolving the contradiction without compromising wideband matching performance.
2Power
If amplifier elements with nonlinear characteristics are used, then power amplification is achieved, but distortion and harmonic generation occur
Solution Approach 1:
The invention converts the harmful harmonic frequencies generated by nonlinear amplification into a controllable parameter by designing LC resonant circuits with resonant frequencies matching the harmonic frequencies. This transforms the harmful effect into a manageable characteristic that can be selectively suppressed, maintaining power amplification while reducing distortion.
Solution Approach 2:
The invention changes the impedance parameters at harmonic frequencies by introducing LC series resonant circuits. At resonant frequencies, these circuits present a low impedance path that shunts harmonic currents, effectively changing the electrical characteristics at distortion frequencies while maintaining normal amplification characteristics in the desired band.
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 suppresses harmonic output from the power amplifier circuit, enhancing the bandpass characteristics and enabling efficient operation by aligning resonant frequencies with harmonic frequencies, thus reducing distortion.
Implementation Method 1
an output-side winding that is coupled to the input-side winding via an electromagnetic field
Implementation Method 2
resonant frequencies of the first LC series resonant circuit and the second LC series resonant circuit are caused to coincide with the frequency of any harmonic of a plurality of harmonics
Data Source
AI summary
A matching network is a matching network of a power amplifier circuit that outputs a signal obtained by a differential amplifier amplifying power of a high-frequency signal. The matching network includes an input-side winding connected between differential outputs of the differential amplifier; an output-side winding that is coupled to the input-side winding via an electromagnetic field and whose one end is connected to a reference potential; a first LC series resonant circuit including a capacitive element and an inductive element connected in series with each other, and being connected in parallel with the input-side winding; and a second LC series resonant circuit including a capacitive element and an inductive element connected in series with each other, and being connected in parallel with the output-side winding.