Negative Permittivity Filtering Device for Common-Mode Noise Suppression
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Solution Overview
Problem
Conventional filtering devices for suppressing common-mode noises in differential signal transmission are limited by their inability to be miniaturized and performance degradation with shielding structures, despite their effectiveness in wideband frequency suppression.
Innovation Solution
A filtering device comprising a differential transmission line, a grounding layer, a dielectric unit, and a conductive structure with a stacked configuration that creates an effective negative permittivity, utilizing meandering and spiral conductive traces and via units to enhance capacitance and inductance, forming a metamaterial structure that suppresses common-mode noises.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional filtering devices use patterned grounding structures to suppress common-mode noises, then common-mode noise suppression is improved, but device size cannot be miniaturized because the structure dimensions must be one half or one quarter of the wavelength
Solution Approach 1:
The patent changes the electromagnetic parameters of the filtering device by introducing a conductive structure with specific geometry (width w, length l, spacing d) that creates effective negative permittivity. This parameter change allows the device to achieve common-mode noise suppression without requiring dimensions based on wavelength fractions, enabling miniaturization while maintaining suppression effectiveness.
Solution Approach 2:
The patent creates a composite structure by combining the differential transmission line, dielectric unit, grounding layer, and conductive structure. This composite configuration produces effective negative permittivity, which is a material property that enables the filtering function in a compact form factor, resolving the contradiction between noise suppression and device size.
2Object-affected harmful factors
If conventional filtering devices use patterned grounding structures for wideband suppression, then common-mode noise suppression is improved, but performance degrades when shielding structures are included
Solution Approach 1:
The patent introduces a dielectric unit as an intermediary between the differential transmission line and the grounding layer. This dielectric medium with specific permittivity serves as a mediator that enables the conductive structure to achieve effective negative permittivity while maintaining stable performance. The dielectric unit buffers the interaction between components, preventing performance degradation that would occur with direct shielding structures.
3Object-affected harmful factors
If the conductive structure is designed with specific dimensions to achieve negative permittivity, then common-mode noise suppression is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent addresses manufacturing precision challenges by optimizing the geometric parameters (width w, length l, spacing d) of the conductive structure to achieve effective negative permittivity. By carefully designing these dimensions, the patent creates a configuration that is relatively insensitive to manufacturing tolerances, allowing the device to achieve common-mode noise suppression without requiring extremely tight manufacturing precision.
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 solution effectively miniaturizes the filtering device while maintaining desired bandgap frequencies, achieving improved common-mode noise suppression with increased insertion loss, enhancing the device's noise reduction capabilities.
Implementation Method 1
cooperates with the differential transmission line, the grounding layer and the dielectric unit to form a stacked structure that has an effective negative permittivity, thereby suppressing the common mode noises coupled to the conductive traces
Implementation Method 2
The dielectric unit is disposed between the differential transmission line and the grounding layer
Data Source
AI summary
A filtering device is capable of suppressing common mode noises upon transmission of a differential signal, and includes a differential transmission line, a grounding layer, a dielectric unit and a conductive structure. The differential transmission line has a pair of conductive traces spaced apart from each other. The grounding layer is spaced apart from the differential transmission line. The dielectric unit is disposed between the differential transmission line and the grounding layer. The conductive structure is embedded in the dielectric unit, is coupled electrically to the conductive traces and the grounding layer, and cooperates with the differential transmission line, the grounding layer and the dielectric unit to form a stacked structure that has an effective negative permittivity, thereby suppressing the common mode noises coupled to the conductive traces. A differential signal transmission circuit is also disclosed.