LC Filter Inductor Geometry for Coupling Reduction
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Solution Overview
Problem
Existing low pass filters using three-dimensional spiral inductors experience insufficient attenuation in bands outside the pass band due to strong electromagnetic coupling between inductors, leading to increased insertion loss.
Innovation Solution
The electronic component employs a configuration of LC parallel resonators with inductors arranged in a spiral shape for the first and last positions and a helical inductor in the middle, reducing electromagnetic coupling by increasing the distance between inductors and optimizing the air-core diameter for reduced insertion loss and enhanced attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If three-dimensional spiral inductors are arranged linearly with coinciding winding axes, then insertion loss is reduced due to higher Q factor, but attenuation in bands other than pass band deteriorates due to intensified electromagnetic coupling
Solution Approach 1:
The patent applies local quality by differentiating the shapes of inductors at different positions within the filter. Specifically, the first and last inductors are configured as three-dimensional spiral inductors to minimize insertion loss at the input and output, while intermediate inductors are configured as planar spiral inductors to reduce electromagnetic coupling with adjacent components. This localized differentiation allows each inductor to perform its specific function optimally without compromising the overall filter performance.
2Reliability
If three-dimensional spiral inductors are used, then Q factor is improved and insertion loss is reduced, but electromagnetic coupling between inductors intensifies
Solution Approach 1:
The patent implements local quality by assigning different inductor configurations to different positions in the filter circuit. The first and last inductors (L1 and L3) are designed as three-dimensional spiral inductors to achieve high Q factors and low insertion loss at the signal entry and exit points. The intermediate inductors (L2 and others) are designed as planar spiral inductors with optimized spacing and orientation to minimize electromagnetic coupling with adjacent inductors, thus resolving the contradiction between maintaining high Q factor and reducing harmful electromagnetic interactions.
3Volume of moving object
If inductors are positioned close to each other for compact arrangement, then device size is reduced, but electromagnetic coupling increases causing poor attenuation
Solution Approach 1:
The patent applies local quality by using different inductor geometries at different positions to balance compactness and electromagnetic coupling reduction. The three-dimensional spiral inductors at the ends maintain small footprint while the planar spiral inductors in the middle are positioned with optimized spacing and orientation to reduce coupling. This allows the overall device to remain compact while achieving sufficient attenuation in stop bands.
Solution Approach 2:
The patent employs dimensionality change by transitioning from three-dimensional spiral inductors to planar spiral inductors for intermediate positions. This dimensional reduction allows better spatial arrangement and control of electromagnetic fields, enabling compact placement while minimizing unwanted coupling effects through optimized planar geometry and positioning.
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 sufficient attenuation in bands outside the pass band while minimizing insertion loss by reducing electromagnetic coupling and optimizing inductor design, resulting in improved filter performance.
Implementation Method 1
first through n-th LC parallel resonators respectively include first through n-th inductors and first through n-th capacitors
Implementation Method 2
The first through n-th inductors are disposed in the device body such that the first through n-th inductors are arranged in a first direction
Implementation Method 3
first through n-th LC parallel resonators respectively include first through n-th inductors and first through n-th capacitors
Implementation Method 4
LC parallel resonators connected in series with each other, each being constituted by a three-dimensional spiral inductor and a capacitor
Data Source
AI summary
An electronic component includes a device body and first through n-th LC parallel resonators connected in series with each other. The first through n-th LC parallel resonators respectively include first through n-th inductors and first through n-th capacitors. The first through n-th inductors are disposed in the device body such that they are arranged in a first direction in this order. The first and n-th inductors are provided with a spiral shape such that they turn around respective winding axes extending along the first direction. At least one of the second through (n−1)-th inductors is provided with a helical shape such that it turns around a winding axis extending along the first direction.