Laminated LC Filter Magnetic Coupling Attenuation
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Solution Overview
Problem
Laminated LC filters face challenges in achieving high attenuation characteristics near the pass band while maintaining a wide pass band, as existing designs often result in insufficient attenuation of attenuation poles, particularly on the higher frequency side.
Innovation Solution
The design incorporates a multilayer body with dielectric layers, line electrodes, capacitor electrodes, and via electrodes, where inductor loops of odd and even numbered-stage LC parallel resonators are disposed at an angle for magnetic coupling, and the ground-side via electrode portions are integrated to enhance magnetic coupling between inductors, thereby providing an attenuation pole with sufficient attenuation near the pass band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inductors are arranged in a conventional configuration, then the pass band width is maintained, but the attenuation near the pass band is insufficient
Solution Approach 1:
The patent applies asymmetry by configuring the loops of inductors L2 and L3 with different winding directions (one clockwise, one counter-clockwise). This asymmetric arrangement creates an attenuation pole near the pass band while maintaining a wide pass band, resolving the contradiction between attenuation characteristics and pass band width.
Solution Approach 2:
The patent introduces a new dimension of control by utilizing the winding direction (clockwise or counter-clockwise) of inductor loops as an additional degree of freedom. This dimensional change allows independent optimization of both pass band width and attenuation characteristics without compromising either parameter.
2Reliability
If the winding directions of inductor loops are made different to provide attenuation, then attenuation characteristics improve, but the magnetic coupling strength decreases
Solution Approach 1:
The patent applies local quality by making each inductor loop have a specific winding direction tailored to its position in the filter circuit. Inductors L2 and L3 have opposite winding directions to create the attenuation pole, while other inductors maintain winding directions optimized for their respective functions, allowing localized optimization of both attenuation and magnetic coupling.
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 achieves high attenuation characteristics while maintaining a wide pass band, with strengthened magnetic coupling between inductors in the LC parallel resonators, improving the filter's frequency response.
Implementation Method 1
the loops of the inductors of at least a pair of the LC parallel resonators in at least one of a pair of odd numbered-stage LC parallel resonators and a pair of even numbered-stage LC parallel resonators among at least the four LC parallel resonators are disposed at an angle at which magnetic coupling is obtained between each other
Data Source
AI summary
In a laminated LC filter, at least four LC parallel resonators are provided inside a multilayer body. At least a pair of loops of inductors in odd numbered-stage LC parallel resonators among the at least four LC parallel resonators are disposed at an angle at which magnetic coupling is obtained therebetween, and winding directions thereof are the same, so as to obtain magnetic coupling between the inductors. In addition, magnetic coupling may also be obtained between a pair of loops of inductors in even numbered-staged LC parallel resonators among the at least four LC parallel resonators.