RF Amplifier LC Resonance for Unwanted Signal Suppression
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Solution Overview
Problem
Existing radio frequency amplifiers, such as those described in Japanese Unexamined Patent Application Publication No. 2001-292039, have a large circuit size due to numerous components, leading to issues with suppressing unnecessary signals.
Innovation Solution
Incorporating an inductor connected between the output and input of an amplifier stage to form an LC parallel resonant circuit, which increases impedance at specific frequencies, thereby reducing the amplitude of unwanted signal components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pre-distortion compensation circuit is used to suppress intermodulation distortion, then signal quality is improved, but circuit size increases due to a large number of circuit components
Solution Approach 1:
The patent extracts and eliminates unnecessary circuit components from the pre-distortion compensation circuit while retaining the essential functionality for suppressing intermodulation distortion. This reduces circuit size without significantly compromising signal quality.
Solution Approach 2:
The patent merges the pre-distortion compensation function with the existing amplifier structure by strategically placing inductors within the amplifier stage. This integration eliminates the need for separate compensation circuits, thereby reducing overall circuit size while maintaining signal quality.
2Reliability
If multiple circuit components are used to suppress unnecessary signals, then signal purity is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by placing inductors with specific impedance characteristics at particular locations within the amplifier circuit where they are most effective. This targeted approach suppresses unwanted signals without requiring complex circuitry throughout the entire device.
Solution Approach 2:
The patent changes the impedance parameters of the amplifier circuit by introducing inductors with specific inductance values. This modifies the circuit's frequency response to suppress intermodulation distortion products, achieving signal purity through parameter optimization rather than complex circuit architecture.
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 proposed configuration reduces the circuit size by minimizing the number of components while effectively suppressing unwanted signal frequencies, achieving a maximum intensity reduction of approximately 20 dBm compared to previous designs.
Implementation Method 1
Incorporating an inductor connected between the output and input of an amplifier stage to form an LC parallel resonant circuit, which increases impedance at specific frequencies
Data Source
AI summary
A radio frequency amplifier includes at least one amplifier stage. The radio frequency amplifier includes a first amplifier including an output that is electrically connected to an output terminal of the radio frequency amplifier and an input that receives a radio frequency signal, and an inductor including a first end that is electrically connected to the output of the first amplifier and a second end that is electrically connected to the input of the first amplifier.