Power Amplifier Output Filtering for Wideband Harmonic Attenuation
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Solution Overview
Problem
Existing power amplifier circuits face challenges in attenuating harmonic components over a wide frequency range, particularly with the increasing transmission capacities in mobile communication devices, leading to insufficient bandwidth in harmonic attenuation.
Innovation Solution
A power amplifier circuit design incorporating two filter circuits with specific frequency characteristics, each comprising a capacitor and an inductor connected in series between the output terminal and ground, allowing for effective attenuation of Nth-order harmonics, where N is an integer greater than or equal to 2, thereby enhancing harmonic attenuation over a wider range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single filter circuit is used to attenuate harmonic components, then the circuit structure is simple, but the bandwidth of harmonic attenuation is insufficient
Solution Approach 1:
The patent divides the single filter circuit into multiple filter circuits (first filter circuit and second filter circuit) connected in parallel. Each filter circuit has different frequency characteristics, allowing them to collectively cover a wider frequency range for harmonic attenuation while maintaining individual circuit simplicity.
2Adaptability or versatility
If multiple filter circuits are used to widen the attenuation bandwidth, then the harmonic attenuation bandwidth is improved, but the device complexity increases
Solution Approach 1:
The patent segments the filtering function into multiple parallel filter circuits, each handling specific frequency ranges. This segmentation allows the system to achieve wide bandwidth attenuation without making any single filter circuit overly complex.
Solution Approach 2:
Each filter circuit is designed with universal applicability to handle different harmonic frequencies. By configuring multiple filter circuits with complementary frequency characteristics, the system achieves multi-functionality in attenuating various harmonic components across a wide bandwidth.
3Object-generated harmful factors
If filter circuits are added to attenuate harmonics, then the harmonic attenuation performance is improved, but the loss in fundamental frequency increases
Solution Approach 1:
Each filter circuit is designed with specific local quality characteristics tailored to target particular harmonic frequencies. By assigning different frequency characteristics to different filter circuits, the system can selectively attenuate harmonics while preserving the fundamental frequency with minimal loss.
Solution Approach 2:
The patent converts the potential harm of fundamental frequency loss into a benefit by carefully designing the filter circuits' frequency characteristics. The filter circuits are configured to reject harmonics while maintaining high impedance at the fundamental frequency, thus converting the filtering action into a beneficial harmonic suppression without significant fundamental frequency degradation.
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 design achieves improved harmonic attenuation over a wider range, reduces distortion, and increases power added efficiency by halving the resistance component and moving impedance towards the short-circuit side, while minimizing loss in the fundamental frequency.
Implementation Method 1
a first filter circuit having a frequency characteristic that attenuates an Nth-order harmonic of the amplified signal... The first filter circuit includes a first capacitor and a first inductor, which are connected in series between the output terminal and ground
Data Source
AI summary
A power amplifier circuit includes a power amplifier that amplifies an input signal and outputs the amplified signal from an output terminal thereof, a first filter circuit that has a frequency characteristic that attenuates an Nth-order harmonic of the amplified signal, N that is an integer greater than or equal to 2, and a second filter circuit that has a frequency characteristic that attenuates the Nth-order harmonic of the amplified signal. The first filter circuit includes a first capacitor and a first inductor. The first capacitor and the first inductor are connected in series between the output terminal and ground. The second filter circuit includes a second capacitor and a second inductor. The second capacitor and the second inductor are connected in series between the output terminal and ground.