Power Amplifier Circuit Using Second-Harmonic Cancellation
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Solution Overview
Problem
Existing power amplifier circuits face challenges in achieving high output while reducing intermodulation distortion, particularly with the increasing number of frequency bands and filter circuits due to the introduction of new communication standards like 4G and 5G, leading to enlarged circuit size and increased transmission loss.
Innovation Solution
A power amplifier circuit design incorporating a divider circuit, a second-harmonic-wave generating circuit, and a first amplifier circuit, which divides input signals into phases to cancel fundamental waves and combine second harmonic waves, allowing for high output and reduced intermodulation distortion without the need for filter circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If filter circuits are used to extract second harmonic waves for intermodulation distortion compensation, then intermodulation distortion is reduced, but circuit size is enlarged and transmission loss increases
Solution Approach 1:
The patent extracts only the necessary function (second harmonic wave generation) from the filter circuit using a dedicated second-harmonic-wave generating circuit. This circuit selectively generates second harmonic waves while allowing fundamental waves to be canceled, eliminating the need for bulky filter circuits that previously performed both frequency selection and signal cancellation functions.
Solution Approach 2:
The patent replaces the mechanical/filter-based frequency selection approach with an electronic signal processing approach. By using active circuits to generate and combine second harmonic waves with specific phase relationships, the system achieves frequency discrimination without physical filters, reducing circuit size and transmission loss.
2Object-generated harmful factors
If filter circuits are used to extract second harmonic waves for intermodulation distortion compensation, then intermodulation distortion is reduced, but transmission loss increases
Solution Approach 1:
The patent extracts only the necessary function (second harmonic wave generation) from the filter circuit using a dedicated second-harmonic-wave generating circuit. This circuit selectively generates second harmonic waves while allowing fundamental waves to be canceled, eliminating the need for bulky filter circuits that previously performed both frequency selection and signal cancellation functions.
Solution Approach 2:
The patent replaces the mechanical/filter-based frequency selection approach with an electronic signal processing approach. By using active circuits to generate and combine second harmonic waves with specific phase relationships, the system achieves frequency discrimination without physical filters, reducing circuit size and transmission loss.
3Adaptability or versatility
If multiple filter circuits are added to handle increasing frequency bands, then communication standards compliance is improved, but device complexity increases
Solution Approach 1:
The patent creates a universal second-harmonic-wave generating circuit that can handle multiple frequency bands through a single unified approach. Rather than implementing separate filter circuits for each frequency band, this circuit generates second harmonic waves that can compensate for intermodulation distortion across different frequency ranges, reducing the number of required circuits while maintaining multi-band capability.
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 enables high output power amplification with reduced intermodulation distortion, maintaining circuit efficiency and compactness by eliminating the need for filter circuits and minimizing signal cancellation effects.
Implementation Method 1
The second-harmonic-wave generating circuit combines the first signal and the second signal with each other so that a fundamental wave of the first signal and a fundamental wave of the second signal cancel each other out and so that a signal having a frequency band of a second harmonic wave of the first signal and a signal having a frequency band of a second harmonic wave of the second signal are added to each other
Data Source
AI summary
A power amplifier circuit includes a divider circuit, a second-harmonic-wave generating circuit, and a first amplifier circuit. The divider circuit divides an input signal into a first signal and a second signal and outputs the first signal to a main path and the second signal to a sub-path. The first signal and the second signal are out of phase with each other by substantially 180 degrees. The second-harmonic-wave generating circuit is disposed on the sub-path and combines the first signal and the second signal with each other so that a fundamental wave of the first signal and that of the second signal cancel each other out and so that a signal having a frequency band of a second harmonic wave of the first signal and that of a second harmonic wave of the second signal are added to each other, thereby generating a second-harmonic-wave combined signal.