RF Power Amplifier Circuit for Harmonic and Stray Suppression
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Solution Overview
Problem
Radio frequency power amplifiers generate harmonic waves and stray outputs, which interfere with receiver inputs and adjacent channels, necessitating improved designs that inhibit both harmonic waves and stray outputs to enhance linear performance and prevent interference.
Innovation Solution
A radio frequency power amplifier design incorporating a power source, LDO circuit, harmonic wave inhibiting unit, stray inhibiting unit, and low-pass matching network, where the harmonic wave inhibiting unit is an LC array and the stray inhibiting unit consists of cascaded loads with isolation inductors, and the low-pass matching network is a multi-level network to filter out harmonic waves and stray signals at resonance frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a radio frequency power amplifier works in a nonlinear region to increase signal power, then the output power is improved, but harmonic waves and strays are generated that interfere with receiver inputs and adjacent channels
Solution Approach 1:
The patent divides the power amplifier into multiple stages (first power amplifying stage and second power amplifying stage) with different functions. The first stage operates in nonlinear region for power amplification, while the second stage operates in linear region for signal purification. This segmentation allows the system to achieve both high output power and low harmonic distortion by assigning different operating modes to different segments of the amplification process.
Solution Approach 2:
The patent introduces an isolating amplifier as an intermediary component between the nonlinear power amplifying stage and the output. This isolating amplifier acts as a mediator that receives the amplified signal containing harmonics and converts it into a clean sinusoidal output signal, thereby eliminating the harmful harmonic waves and strays generated by the nonlinear amplification process while preserving the power gain.
2Reliability
If multiple inhibition networks are added to suppress harmonic waves and strays, then the linear performance is improved, but the device complexity increases
Solution Approach 1:
The patent combines the functions of power amplification and signal purification into a unified two-stage amplifier system. The first power amplifying stage and second power amplifying stage are integrated in sequence, where the first stage provides nonlinear power amplification and the second stage provides linear signal conditioning. This merging of functions into a coordinated multi-stage system achieves effective harmonic suppression without requiring separate, complex inhibition networks, thereby improving linear performance while controlling 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 inhibits harmonic waves and stray outputs at resonance frequencies, reducing output stray and improving linear performance by simplifying the amplifier's design complexity and lowering costs, while ensuring impedance matching and interference avoidance.
Implementation Method 1
a plurality of resonance frequencies are generated by means of the low-pass matching network, and a harmonic wave and stray of a radio frequency signal amplified by the amplifying unit at the resonance frequencies are inhibited
Implementation Method 2
A plurality of resonance frequencies are generated by means of the harmonic wave inhibiting unit, and the harmonic wave and stray of the power source at the resonance frequencies are inhibited
Data Source
AI summary
Disclosed are a radio frequency power amplifier for inhibiting a harmonic wave and stray, a chip and a communication terminal. The radio frequency power amplifier comprises a power source, an LDO circuit, a harmonic inhibition unit, a stray inhibition unit, an amplifying unit, and a low-pass matching network. On the one hand, by means of the power source being connected to the harmonic inhibition unit, harmonic waves and stray of the power source at a resonant frequency are inhibited. Additionally, by means of the stray inhibition unit reducing the gain of the amplifying unit at a resonant frequency, output of stray is reduced. On the other hand, by means of the low-pass matching network being embedded at an output end of the radio frequency power amplifier, harmonic waves and the stray of a radio frequency signal amplified by the amplifying unit at different frequencies is effectively inhibited.