Isolated-Ground Matching Circuit for RF Harmonic Attenuation
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Solution Overview
Problem
In mobile communication terminals, the interference between circuit elements sharing a common ground in matching circuits makes it difficult to sufficiently attenuate harmonic components of RF signals.
Innovation Solution
A matching circuit configuration with isolated grounds for low pass and high pass filters reduces interference, allowing for effective attenuation of harmonic components by using a combination of filters and resonant circuits to match impedance and filter out harmonics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If circuit elements share a common ground, then device complexity is reduced, but harmonic component attenuation becomes insufficient
Solution Approach 1:
The ground system is segmented into multiple independent ground nodes (first ground node for low pass filter, second ground node for high pass filter) instead of using a single common ground. This segmentation isolates the ground paths of different filter circuits, preventing mutual interference while maintaining circuit functionality.
Solution Approach 2:
A ground isolation mechanism is introduced as an intermediary between the low pass filter ground and high pass filter ground. This isolation structure acts as a mediator that allows each filter to have its own ground reference without direct interaction, thereby eliminating harmful interference between the two filter circuits.
2Object-generated harmful factors
If ground isolation is implemented, then harmonic component attenuation is improved, but device complexity increases
Solution Approach 1:
The ground system is segmented into multiple independent ground nodes (first ground node for low pass filter, second ground node for high pass filter) instead of using a single common ground. This segmentation isolates the ground paths of different filter circuits, preventing mutual interference while maintaining circuit functionality.
Solution Approach 2:
Different ground configurations are applied locally to different parts of the circuit. The low pass filter uses a ground configuration optimized for its frequency range, while the high pass filter uses a separate ground configuration suited to its characteristics. This local optimization allows each filter to perform its function effectively without compromising the other.
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 improves signal loss for harmonic components by 0.6 dB to 6.0 dB, achieving better attenuation and maintaining ideal ground conditions, thus enhancing the performance of power amplification modules in mobile communication terminals.
Implementation Method 1
a low pass filter and a high pass filter... enable sufficient attenuation of the harmonic components of the amplified signal
Data Source
AI summary
A matching circuit performs output impedance matching for an amplifier that amplifies an input signal and outputs an amplified signal. The matching circuit includes a low pass filter and a high pass filter. The ground of the low pass filter and the ground of the high pass filter are isolated from each other.