High-Frequency Switching Module Inductor Integration for Harmonic Attenuation
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Solution Overview
Problem
High-frequency switching modules and RF front-end circuits struggle to adequately attenuate high-order harmonics due to the high cutoff frequency of Chebyshev-type low-pass filters, which results in insufficient attenuation of second or third higher harmonics when the ripple frequency falls within the attenuation band.
Innovation Solution
Integrating an inductor directly and in series with the high-frequency switch and π-type high-frequency filter, shifting the cut-off frequency to a lower frequency side and suppressing ripples by positioning the ripple frequency between second and third higher harmonic bands, thereby enhancing attenuation characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a π-type low-pass filter with shunt capacitors is used to remove high-order harmonics, then the filter structure is simple and easy to manufacture, but the cutoff frequency becomes very high and cannot sufficiently attenuate second or third higher harmonics
Solution Approach 1:
The patent divides the filtering function into two separate stages: a π-type low-pass filter for basic filtering and an additional low-pass filter specifically designed to attenuate high-order harmonics. This segmentation allows each filter to be optimized for its specific function, with the first filter maintaining simplicity and the second filter providing specialized harmonic suppression.
Solution Approach 2:
The patent introduces a series inductor as an intermediary element between the high-frequency switch and the π-type low-pass filter. This inductor forms an LC parallel resonant circuit that creates a Chebyshev-type low-pass filter characteristic, effectively lowering the cutoff frequency and providing better harmonic attenuation while maintaining the overall simplicity of the structure.
2Device complexity
If the cutoff frequency of the low-pass filter is kept high for simple filter design, then the filter structure remains simple, but the ripple frequency falls within the attenuation band causing insufficient harmonic suppression
Solution Approach 1:
The patent makes the filter characteristics adjustable by incorporating variable inductors and capacitors that can be controlled by control signals. This allows the cutoff frequency and ripple characteristics to be dynamically adjusted to precisely position the ripple frequency outside the attenuation band, achieving accurate frequency control without increasing structural complexity.
Solution Approach 2:
The patent changes the electrical parameters (inductance and capacitance values) of the filter components to optimize the cutoff frequency and ripple characteristics. By adjusting these parameters, the ripple frequency is positioned outside the attenuation band, ensuring effective harmonic suppression while maintaining a relatively simple filter configuration.
3Reliability
If an LC parallel resonant circuit is added to form a Chebyshev-type low-pass filter, then the cutoff frequency can be lowered and ripple suppressed, but the device complexity increases
Solution Approach 1:
The patent merges the LC parallel resonant circuit with the existing π-type low-pass filter structure, combining multiple filtering functions into a unified circuit architecture. The series inductor is integrated into the signal path, and its interaction with the shunt capacitors creates the Chebyshev-type response, achieving enhanced harmonic attenuation without requiring completely separate filter structures.
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 effectively suppresses high-order harmonics, achieving desired frequency characteristics and sufficient attenuation in high-frequency switching modules, even when the ripple frequency is within the attenuation band, by adjusting the inductance to position the ripple outside the harmonic bands.
Implementation Method 1
a Chebyshev-type low-pass filter including an inductance component and a capacitor component formed when the high-frequency switching device is turned ON
Implementation Method 2
to remove unwanted waves generated in the transmission paths
Data Source
Figure 1~3
Figure 4(A)~5
Figure 6(A)~6(C)
AI summary
To obtain a high-frequency switching module and a frequency-characteristic adjusting method for a high-frequency circuit in which a desired frequency characteristic can be exhibited and the ripple can be suppressed to a small level. A high-frequency switching module in which a high-frequency switch SW including a diode D, which serves as a switching device, and a high-frequency filter LPF including inductors L and L1 and a capacitor C1a are integrated into each other. The inductor L forming a π-type high-frequency filter is connected directly and in series to the diode D. By inserting the inductor L, the cut-off frequency of a Chebyshev-type low-pass filter circuit formed when the diode D is turned ON can be shifted to a lower frequency side, and also, the ripple can be suppressed to a small level.